Traumatic brain injury (TBI) presents a serious challenge for modern medicine due to the poor regenerative capabilities of the brain, complex pathophysiology, and lack of effective treatment for TBI to date. Tissue-engineered scaffolds have shown some experimental success in vivo; unfortunately, none have yielded consummate results of clinical efficacy. N-acetylcysteine has shown neuroprotective potential. To this end, we developed a N-acetylcysteine (NAC)-loaded poly(lactic-co-glycolic acid) (PLGA) electrospun system for potential neural tissue application for TBI. Scanning electron microscopy showed nanofiber diameters ranging 72–542 nm and 124–592 nm for NAC-free and NAC-loaded PLGA nanofibers, respectively. NAC loading was obtained at 28%, and drug entrapment efficacy was obtained at 84%. A biphasic NAC release pattern that featured an initial burst release (13.9%) stage and a later sustained release stage was noted, thus enabling the prolonged replenishing of NAC and drastically improving cell viability and proliferation. This was evidenced by a significantly higher cell viability and proliferation on NAC-loaded nanofibers for rat pheochromocytoma (PC12) and human glioblastoma multiform (A172) cell lines in comparison to PLGA-only nanofibers. The increased cell viability and cell proliferation on NAC-loaded nanofiber substantiates for the repositioning of NAC as a pharmacological agent in neural tissue regeneration applications.  Traumatic brain injury (TBI) is the greatest contributor to global death and disability among all trauma-related injuries. The global incidence of traumatic brain injury (TBI) is generally reported as ~200 in 100,000 with a mortality of 20 per 100,000 people [This is in part due to the complex evolutionary pathophysiology of TBI. Complete neurological damage does not all occur immediately at the moment of primary injury. Secondary injury (follows within hours of primary TBI) has been identified as the leading cause of in-hospital deaths post TBI . An estiCurrent treatment approaches for TBI are largely focused on preventing further damage  instead of facilitating regeneration . SeveralTissue engineering aims to engender scaffolds based on biological systems, particularly, the nano–micro–macro extracellular matrix environment of the cell to aid in tissue repair and regeneration. Biological systems constitute a myriad of nanoscale structures, and the benefits of the nanotherapies have been widely reported in the literature . In partTissue-engineered biomaterial scaffolds have shown various degrees of experimental success . For insThis study focused on the design of electrospun PLGA nanofibers based on a clinical pharmacological drug, creating a localized therapeutic signal within the nanofibers for brain tissue engineering with optimal porosity, superior surface area to volume ratio, and cell viability and proliferation biocompatibility, which were fabricated from biocompatible materials in order to improve localized drug delivery at the brain lesion site.N-acetylcysteine (NAC). N-acetylcysteine is commonly used to loosen thick mucus in patients with chronic obstructive pulmonary disease (COPD) or cystic fibrosis and an antidote to acetaminophen and carbon monoxide poisoning [The therapeutic focus of the current study will be oisoning ,19. Seveoisoning ,24,25,26oisoning . Althougoisoning ,25, its oisoning ,29,30,31oisoning . In addid-l-lactide-co-glycolide) (PLGA) as the substrate to embed and deliver the therapeutic agent (NAC). Poly(d-l-lactide-co-glycolide) (PLGA) nanofibers have been explored as desirable biomaterials for nanoscale electrospinning in neural tissue engineering [We used poly 85:15 (PLGA) was supplied Ex gratia from Evonik Nutrition & Care GmbH, Essen, Germany. This particular PLGA Resomer 858 used herein is a bioresorbable poly (85:15) grade suitable for pharmaceutical applications such as controlled release and acting as a long acting medication delivery material. N-acetylcysteine (NAC), 2,2,2-trifluoroethanol (≥ 99% GC), formic acid, Dulbecco’s Modified Eagles Medium—high glucose, Roche Cell Proliferation Kit I (MTT), dimethyl sulfoxide (DMSO), and trypsin–EDTA solution were obtained from Sigma Aldrich . Donor Equine Serum (DES) was purchased from Hyclone. Ethanol (99% absolute) was purchased from LabChem, Edenvale, Johannesburg, South Africa. Gibco Fetal Bovine Serum and Ham’s F-12 Nutrient Mix (F12) were purchased from Thermofischer Scientific . Rat (Rattus Norvegicus) adrenal gland pheochromocytoma PC12 and human glioblastoma multiforme A172 cells were purchased from Cellonex . Pencillin/Streptomycin/Amphotericin B (P/S/AB) solution was purchased from Lonza, Oregon, USA.Poly. A 1:1 ratio comprising 2,2,2-trifluoroethanol/formic acid (TFE/FA) electrospinning solvent mixture was prepared. The PLGA and NAC (one part NAC to two parts PLGA) were added to the TFE/FA solvent mixture at room temperature and stirred under magnetic stirring for 2 h. This NAC/PLGA ratio enabled the maximal NAC amount while maintaining electrospinnability of the solution . Then, the solutions were transferred into 10 mL syringes, and a pump was used to dispense the solution through a spinneret (0.8 mm) at a controlled rate of 300 µL/hr. The applied voltage was controlled between 24 and 26 kV. The distance between the spinneret tip and the aluminum-clad rotating cylindrical collector was set at 200 mm with the collector rotating at 400 rpm and a stroke velocity of 200. The pure PLGA electrospun scaffold was subsequently used as the control. Electrospinning experiments were performed at room temperature under the relative humidity of ≤ 40%. The resultant nanofibers were subsequently collected and vacuum dried for 24 h at room temperature for the removal of any residual solvent.−1 wavelength range on a Nicolet Impact 400D FTIR Spectrophotometer coupled with Omnic FTIR research grade software . The presence/absence of specific functional groups was noted and analyzed. Systems need to be stable at the physiological tissue target temperatures in vivo. These processes could lead to significant changes on the polymer and crystal structure of the incorporated NAC. Therefore, FTIR, TGA, DSC, and XRD studies were performed in order to confirm the presence of the NAC in the electrospun fibers and to evaluate the structural changes in the polymer matrix and NAC crystallinity after the electrospinning process. The chemical transitions of the electrospun nanofibers before and after NAC loading were determined using a Fourier Transform Infrared (FTIR) spectrometer  fitted with a universal ATR Polarization Accessory . The samples were analyzed at high resolution over a 4000–650 cm−1. Thermograms were recorded in the temperature range of 30–600 °C with a heating rate of 10 °C/min, revealing the mass changes with increasing temperature, thermal stability, and degradation temperature of the sample material.Effects of NAC-loading on thermal stability were characterized using thermogravimetic analysis . Samples (10–15 mg) were placed in an unsealed ceramic pan under nitrogen atmosphere at a flow rate of 20 mL.min−1. Heating took place under nitrogen atmosphere  at a flow rate of 200 mL·min−1, acting as the purge gas to reduce oxidation. The thermal profiles were analyzed. The effects of NAC-loading on thermal transitions was characterized using differential scanning calorimetry (DSC) . Dried samples (5–10 mg) were weighed into aluminum crucible pans (40 mL) and sealed shut. Thereafter, samples were heated at a temperature range of 10–300 °C at a rate of 10 °C·minθ from 3° to 90° at room temperature. XRD was operated at a voltage of 40 kV, a current of 15 mA at a scan step of 0.02°, and a speed of 10°/min. Integrated X-ray Powder Diffraction software  was employed for sample analysis.Amorphization of NAC will contribute to improved solubility and increased NAC at the target site. X-ray diffraction (XRD) studies were performed using an X-ray diffractometer  to obtain information about the crystalline or amorphous state of NAC after electrospinning. The X-ray diffractograms were attained with the scanning scope of 2The size and morphological characteristics of all electrospun scaffolds were characterized utilizing scanning electron microscopy (SEM) FEI Nova NanoLab SEM . Gold isotope and carbon were used to sputter coat the sample using the Micromeritics Porositometer ; surface areas, pore sizes, shapes, and distributions can be measured according to the parameters presented in ® Spectro analytical Software  through ultraviolet spectroscopy at a wavelength of 224 nm. Scaffold hydrophilicity can impact the NAC release rate; therefore, the hydrophilicity of the nanofiber systems was evaluated using the DataPhysics Instruments contact angle goniometer by measuring the water contact angle using the sessile drop method. The nanofiber mats were placed on the testing plate and kept smooth. Subsequently, 2 µL of distilled water was dispensed onto the surface at a dosing rate of 2 µL/s using a Hamilton syringe. The images of the water droplet were recorded by camera software after the droplet was stable. Thereafter, the water contact angle was measured using the SCA202 version 4.1.12 build 1019 software. Five different samples were measured, and the average values were calculated. Drug entrapment efficiency, drug loading, and cumulative NAC release from the scaffolds was quantified by WinASPECT2 atmosphere at 37 °C. Before the test was performed, the nanofibers were cut into 0.5 × 0.5 cm mats and sterilized under UV light for 30 min . The sterilization of scaffolds is a crucial step relating to the applications for tissue engineering in vitro and ultimately, clinical use of the biomaterial scaffold. Braghirolli and co-workers evaluated the effects of sterilization methods on electrospun PLGA nanofibers and the subsequent adhesion efficacy of mesenchymal stem cells. Their observation noted that other methods of sterilization such as ethanol (70%) or using an antimicrobial solution resulted in morphological and structural alterations to the scaffold, respectively [4 cells per well. Absorbance was measured at 570 nm with a background subtraction at 690 nm using a multi-plate reader . The absorbance reading of the blank (690 nm) was subtracted from all the samples.The PC12 cells were cultured in F12 media containing 15% DES, 2.5% FBS, and 1% P/S/AB solution. The A172 cells were cultured in Dulbecco’s Modified Eagles Medium (DMEM) supplemented with 20% FBS and 1% P/S/AB solution. Both cell lines were maintained under 5% COectively . UV ster−1 are present due to the alkyl groups [−1 and C-O bands in the 1067–1454 cm−1 region of both spectra, indicating the presence of the ester group , which can be used as evidence of success in NAC loading. Moreover, the presence of both NAC and PLGA were discerned in the FTIR spectra of NAC-loaded nanofibers. In comparison to the PLGA nanofiber spectrum, the composite NAC-loaded PLGA spectrum showed additional peaks at 1533 cm−1 (amide II), 1606 cm−1 (amide I), 1710 cm−1 (carboxylic group), 2548 cm−1 (S-H), and a low-intensity peak at 3375 cm−1 (NH), respectively, indicating the presence of NAC in the nanofibers. The FTIR spectra of native PLGA and the PLGA nanofibers characterized by bands in the regions 2995 and 2947 cml groups ,40 and cer group . These gonset and Tdeg.max for bulk PLGA and PLGA nanofibers obtained from electrospinning indicates the good preservation of polymer thermal properties during nanofiber fabrication. However, the PLGA nanofibers were more reactive than the native PLGA, in part due to their larger surface area, and consequently, they suffered thermal decomposition more quickly. However, the thermal decomposition Tonset was well above the physiological temperatures in vivo. NAC weight loss was observed in the range 170–600 °C, which was attributed to thermal decomposition. Two significant mass loss stages (168–245 °C and 282–362 °C) were observed for the NAC-loaded PLGA nanofibers attributed to the presence of both NAC and PLGA in the nanofibers. This observation was also confirmed by DSC and XRD, reinforcing the idea that NAC exists in both the amorphous and crystalline phases. The second decomposition temperature range of NAC-loaded PLGA nanofibers is similar to that of bulk PLGA, which is indicative of the preservation of polymer (PLGA) thermal properties during nanofiber fabrication. The initial degradation temperature of NAC when loaded in the nanofibers is higher, suggesting an improvement in thermal stability in comparison to the NAC alone in vivo. The thermal degradation temperature for the NAC/PLGA nanofibers is well above the physiological and processing temperature. Therefore, the fabrication process did not induce significant NAC/PLGA losses, and the NAC-loaded nanofibers have potential thermal stability properties at ambient and physiological temperatures.Thermogravimetric analysis was conducted to evaluate the thermal stability and extension of degradation effects during processing by comparing the native PLGA and NAC and the resultant scaffold . ThermogDrug distribution in the PLGA nanofibers as a function of NAC loading was studied by XRD and DSC analysis. Blend electrospinning was used to fabricate NAC-loaded PLGA nanofibers. With blend electrospinning, the NAC and polymer are present in one solution; this allows the hydrophilic small molecular drug, NAC, to be incorporated not only on the surface of the nanofibers, but it also enables physical entrapment of the NAC inside the polymer matrix of the nanofibers . The X-rg) bulk PLGA and NAC-loaded PLGA nanofibers were observed at approximately 59 and 51 °C, respectively (g of the NAC-loaded PLGA nanofibers was slightly lower than that of the bulk PLGA due to the larger surface area to volume ratio of the electrospun nanofibers as well as the improved orientation of molecular chains [g (glass transition temperature) of the PLGA and NAC/PLGA nanofibers were all above the physiological temperature of 37 °C. Therefore, the nanofibers potentially possess a fairly stable chain structure and enough mechanical strength at ambient and physiological temperatures to be fabricated into thermostable implants/delivery devices.The NAC-loaded nanofibers displayed a much weaker intensity than that of the PLGA-only nanofibers, indicating a different a lesser degree of crystallinity/ordered structure. Moreover, the diffraction peaks of the NAC crystals were absent in the XRD pattern of NAC-loaded nanofibers, and only the XRD pattern characteristic of the PLGA was observed. These results strongly suggest that electrospinning the NAC/PLGA blend may have resulted in the NAC molecule simultaneously (1) dissolved in the polymer matrix and (2) dispersed in and throughout the nanofiber matrices . This reectively b. The Tgr chains . An endor chains . The DSCThe morphological characteristics, orientation, and diameter distribution of the electrospun nanofibers are shown in the SEM images . The eleNanofiber diameters ranged 72–542 nm and 124–592 nm for NAC-free and NAC-loaded PLGA nanofibers, respectively . The ave−1. The high surface area noted for PLGA is attributable to the nanoarchetype that will potentially enhance the surface area for cell–substrate contact and provide a large surface area for cells to adhere in vivo. The lowered NAC/PLGA nanofiber surface area (82.9030 m²·g−1) in comparison could be attributed to the larger diameter of the fibers. The isotherm is not closed, which may be due to the swelling phenomenon due to the formation of very narrow slip pores or bottle-shaped pores present over the microporous structure. Nitrogen adsorption below the relative pressure of P/Po < 1 was indicative of the formation of micropores [The interconnected porous structure is ideal, as it will aid in functioning as a temporary reservoir for the accumulation of the NAC and facilitating the permeability of the nanofibers for uninterrupted passage of cells, nutrients, and waste in the implant site. The high surface area and porous nature of the scaffold was further confirmed by BET analysis. cropores . The nanYield stress is vital to the translational success when choosing a material for structural purposes such as a scaffold. As a support structure, the scaffold needs to be robust enough to structurally accommodate tissue repair needs  and the implantation process. Simultaneously, it must possess an elastic modulus similar to that of neural tissue and have the ability to encourage neuronal viability and extension . The tenA NAC encapsulation efficiency (DEE) value of 84% was calculated for the NAC-loaded PLGA nanofibers at 28% NAC loading. This high DEE can be attributed to the method of nanofiber formation, where electrospinning of the NAC polymer solution ensures that the NAC is entrapped within the nanofibers during fiber formation, and therefore, the NAC is embedded within the solid nanofibers. The hydrophilicity of the nanofibers determined by water contact angle measurement can actively influence the extent to which water diffuses through the scaffold . In turnFollowing brain injury, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced, which leads to cell and tissue death  . HoweverAccording to ISO 10993-5, the PLGA and NAC-loaded PLGA nanofibers were non-toxic to both PC12 and A172 cell lines, as their percentage viability values were well above 80% . This isA percentage cell viability higher than that of the control was observed with the nanofibers . This suThe percentage viability on NAC-loaded nanofibers was higher than that of the NAC-free nanofibers. Ramburrun also noted an increase in neuronal cell (PC12) proliferation compared to NAC-free poly (PHBV) blended with magnesium-oleate (MgOl) fibrous films ascribed to NAC incorporation into the nanofiber system . This maBiomimetic NAC-loaded PLGA nanofibers were produced via electrospinning. The presence, interactions between the native PLGA and the scaffold, and chemical integrity and performance of the nanosystem were confirmed by detailed physicochemical and physicomechanical studies. Scanning electron microscopy revealed the formation of a 3D nanofibrous structure with interconnected pores to support nutrient, oxygen, and cell migration as well as enable integrate surrounding cells into the scaffold within the ECM of brain tissue. In vitro release experiments of NAC demonstrated a biphasic release profile comprising an initial phase of 13.9% release within 8 h followed by more sustained release for a further 240 h. This is ideal for the nanosystem to function as a reservoir and elute the neuroprotective NAC at a TBI lesion. Ex vivo studies confirmed that the NAC-loaded nanosystem was non-toxic toward PC-12 and A172 cells with a positive effect on cell proliferation. Overall, the results showed that the nanosystem has promising potential for simultaneous application in both neural tissue repair and as a neuroprotectant in a spatial and temporal manner from a biomimetic neuroscaffold.


Electrospun polymer nanofibers (EPNFs) as one-dimensional nanostructures are characterized by a high surface area-to-volume ratio, high porosity, large number of adsorption sites and high adsorption capacity. These properties nominate them to be used as an effective adsorbent for the removal of water pollutants such as heavy metals, dyes and other pollutants. Organic dyes are considered one of the most hazardous water pollutants due to their toxic effects even at very low concentrations. To overcome this problem, the adsorption technique has proven its high effectiveness towards the removal of such pollutants from aqueous systems. The use of the adsorption technique depends mainly on the properties, efficacy, cost and reusability of the adsorbent. So, the use of EPNFs as adsorbents for dye removal has received increasing attention due to their unique properties, adsorption efficiency and reusability. Moreover, the adsorption efficiency and stability of EPNFs in aqueous media can be improved via their surface modification. This review provides a relevant literature survey over the last two decades on the fabrication and surface modification of EPNFs by an electrospinning technique and their use of adsorbents for the removal of various toxic dyes from contaminated water. Factors affecting the adsorption capacity of EPNFs, the best adsorption conditions and adsorption mechanism of dyes onto the surface of various types of modified EPNFs are also discussed. Finally, the adsorption capacity, isotherm and kinetic models for describing the adsorption of dyes using modified and composite EPNFs are discussed. Journal of Polymers and the Environment and discussed the applications of EPNFs in water treatment and the discussion was limited only to removing heavy metals [Water pollution is one of the most serious problems that has resulted from industrial development and rapid population growth. This problem has exacerbated over time and has become a global problem due to the increasing the amount of wastewater and its discharge into water systems. Dyeing wastewater is one of the riskiest wastewaters that causes water pollution because of its ability to change the color and the properties of water even in the presence of very low concentrations. Dyeing wastewater usually result from many industries such as textile, cosmetic, tannery, photographs, food and plastic industries. Annually, the estimated production of dyes is around 1.6 million tons and 10–15% of dyes are discharged as wastewater to the environment . The rely metals . Due to Electrospinning is one of the most popular techniques used in the production of polymer nanofibers within the last two decades. This is because of its diversity and simplicity, and its ability to produce nanofibers in various forms with diameters varying from less than one nanometer to several micrometers ,22. The Although the advantages of polymer nanofibers include their high surface area-to-volume ratios and high porosity, some pristine polymers still have limitations in the adsorption process . Some haThe properties of pristine polymer nanofibers can be enhanced via blending of polymer with another polymer in certain ratios . These pThe incorporation of nanomaterials into the polymer nanofibers by dispersing them into the polymer solution and then electrospun is one of the appropriate methods for modifying the surface properties and mechanical properties of polymer nanofibers as well as improving their adsorption capacity. Incorporated nanomaterials must have a good dispersion property in the polymer solution and have the ability to segregate to the surface of nanofibers so that the modification process is effective. Carbon nanomaterials , metal oxide NPs, nano-clay, MOFs and bacteria are the most incorporated materials that used for modifying the surface of polymer nanofibers and applied for the removal of various pollutants.A wet modification is an effective method for the functionalization of the surface of EPNFs, which can be through a chemical reaction between the surface of the nanofibers and functionalized agent in the solution. The surface properties of the modified electrospun polymer nanofibers depend on the nature of the functional agents. This method depends on the presence of functional groups on the surface of EPNFs that are susceptible to reacting with various agents. Polar functional groups on EPNFs can be created through the hydrolysis and aminolysis processes. For example, hydrolysis of polyester, PCL, PLGA and PBGL by alkali solution are the most wet-chemistry reaction for changing the surface properties of nanofibers ,65,66. AGrafting method is an effective way to improve the surface properties of EPNFs such as hydrophilicity and their ability to adsorb ionic pollutants by introducing multiple functional groups . The graSurface coating is carried out by depositing functional material onto the surface of nanofibers with a layer thickness ranging from a few nanometers to several micrometers. The bonding type between them is physical such as electrostatic interaction, π–π interaction and hydrogen bonding interaction. The surface properties such as hydrophilicity and adsorption capacity will depend on the polarity, layer thickness and the homogeneity of the coating material. The coating technique can be completed by various processes such as immersion nanofiber mats into the material solution, self-assembly, layer-by-layer, electrospraying and polymerization onto the surface of nanofibers. For example, PAN nanofibers were fabricated by electrospinning followed by coating with chitosan through the immersion process and was used for dye removal . The res2) onto the surface of polymer nanofibers. The introduction of polar functional groups leads to improvement for the hydrophilicity of EPNFs as well as their ability towards the adsorption of ionic materials onto their surface. A number of hydrophobic polymer nanofibers can be treated by plasma such as PCL [Plasma is one of the post-treatment methods used to increase the adsorption sites onto the surface of nanofibers . The plah as PCL , PLLA [7h as PCL , PLGA [7h as PCL  and PVDFh as PCL . Bai et h as PCL .The adsorption process is a complex process and depends on many factors including the properties of nanofibers, the structure of dyes and the medium of adsorption process.The adsorption capacity of dyes onto the surface of electrospun polymer nanofibers depends on the functional groups, their surface area, their porosity and hydrophilicity/hydrophobicity nature.The properties of polymers differ from each other according to the nature of the functional groups. The adsorption efficiency of polymeric nanofibers varies according to the nature of the functional groups onto their surface. The functional groups can be either in the main structure of polymer nanofibers, or created via surface modification methods.A number of studies have proved that the oxygen-containing functional groups and nitrogen-containing functional groups play a pivotal role in interaction between nanofibers and dyes. For example, the adsorption capacity of PAN nanofibers towards removal of MB and RB was lower than of EDA-PAN nanofibers . This diThe surface area and porosity of many adsorbents plays a pivotal role in the adsorption process. High surface area and porosity of polymer nanofibers enhances the adsorption performance due to the creation of active adsorption sites. Chen et al.  fabricatHydrophilic EPNFs with their polar functional groups have higher adsorption capacity towards the removal of dyes compared to hydrophobic one. Polar functional groups play an important role in wettability of nanofibers surface as well as in reducing the repulsive forces between the surface and the dyes molecules in an aqueous solution. For example, Liu et al. observed that the adsorption capacity of copolyester nanofibers increased from 49.90 to 543.48 mg/g while the contact angle decreased from 135° to 46° upon surface functionalization with carboxymethyl-β-cyclodextrin . In anotmax, (nm) of the dyes addressed in this review.Adsorption of dyes onto the surface of polymer nanofibers and their nanocomposites depends on their molecular structure, molecular size and functional groups. The removal of dyes from aqueous solution by adsorption process is highly dependent on operating conditions like pH, adsorbent dosage, initial concentration of dye, contact time and temperature.The pH is one of the most important factors that affect the adsorption process, due to its effect on the ionization degree of functional groups for both polymer nanofibers and dye. In general, increasing the pH of the adsorption medium enhances the adsorption of cationic dyes due to increasing the electrostatic attraction between the dye and polar groups on the surface of nanofibers and vice versa with anionic dyes. Several studies have examined the effect of pH on the adsorption capacity of polymer nanofibers and their nanocomposites towards dyes removal from an aqueous system. Fan et al. performed the adsorption of cationic dye (MB) and anionic dye (MO) at various pH onto PANF-g-HPEI nanofibers . They foOptimization of adsorbent doses required for complete removal of dye from aqueous solutions is very important to determine the cost-effectiveness of adsorbent. In general, the dye removal percentage increases with increasing the adsorbent dose until certain dose due to the increase of adsorption sites on the adsorbent surface with increasing the amount of adsorbent. In contrast, the adsorption capacity decreases with increasing adsorbent dose due to the mathematical inverse proportional to the adsorbent dosage. Mahmoodi et al. studied the effect of ZIF-8@chitosan/PVA nanofibers dose on the removal of MG dye and they found that the removal percentage increase with increasing the adsorbent dose and the optimum dosage was 0.03 g/L . Almasia2 nanofibers at different concentration of RhB dye [The contact time factor helps in determining the optimum time required to saturate the active adsorption sites on the surface of the nanofibers and complete removal of dye. The adsorption efficiency and adsorption capacity usually increase by increasing the contact time to reach the equilibrium state, then remains steady state thereafter. Most of the studies that used polymer nanofibers as an adsorbent to remove various types of dyes studied the effect of contact time and determined the time required to reach equilibrium. For example, Soltan et al. studied the effect of contact time on the removal of anionic dyes using nylon-6/poly(propylene imine) dendrimer nanofibers . They fo RhB dye . They fo RhB dye . They fo2 and they found that the adsorption capacity increased from 500 to 2357.87 mg/g with increasing the initial concentration of MB from 200 to 1500 mg/L [The adsorption capacity of the nanofibers largely depends on the initial concentration of the dye in the aqueous solution. In general, the adsorption capacity increases with increasing dye concentration due to the increase in the number of dye molecules in the contact area between the surface of the nanofibers and aqueous solution. The increasing in the contact area enhances the driving force of the transferred mass as well as the number of collisions between dye ions and nanofibers surface. In contrast, the percentage of dye removal decreases with an increase in the initial concentration of the dye due to saturation of the active adsorption sites on the surface of the nanofibers, which leads to an increase in the remaining concentration of the dye in the aqueous solution. Wang et al. studied the adsorption of MB onto sodium alginate nanofibers that was crosslinked by CaCl500 mg/L . Almasia500 mg/L . They foThe effect of the temperature on the adsorption of dyes onto EPNFs plays a vital role in interpreting the mechanism of adsorption. In general, increasing the adsorption capacity with increasing the temperature indicates that the adsorption process is endothermic and is exothermic with decreasing the temperature. The increase in the adsorption capacity with increasing the temperature is attributed to higher mobility of the dye molecules and strong interaction between the dye ions and the active adsorption sites on the surface of the nanofibers. For example, the adsorption of MB dye by P(NIPAM-co-βCD)/P(NIAPM-co-MAA)  and DCA/Understanding the adsorption mechanism of dyes onto adsorbent is very essential in order to optimize the adsorption process and improve the nanofiber’s efficiency towards the removal of dyes. Adsorption of dyes onto the surface of nanofibrous materials depends on the conditions of the solution , the nature of the nanofibers  and the nature of the dye . Due to the multiplicity of factors affecting the adsorption process of dyes onto the surface of the nanofibers, the adsorption mechanism may not be explicit. Therefore, it is necessary to conduct isotherm, kinetic, thermodynamic and spectroscopic studies as well as studying the effect of pH to obtain a clear and in-depth view of the adsorption mechanism. As reported from different studies ,111,112,Polymers are characterized by high molecular weights and are divided according to the source into two main parts: natural and synthetic polymers. Some polymers have been used as adsorbents for many pollutants, including dyes, especially those containing effective functional groups and insoluble in water. The efficiency of polymers in dye removal depends on the effective group nature, morphology, surface area and porosity. Converting polymers into nanofibers is one of the most effective ways to improve their efficiency in removing dyes due to the unique properties of nanofibers such as high-water permeability, high surface area and porosity.Polyamide nanofibers are one of the common homopolymers that have been used as an effective adsorbent for the removal of dyes as it is inexpensive, insoluble in water, keeps its morphology during the adsorption process and is reusable . For exaDue to the low adsorption capacity, low mechanical properties and hydrophobic properties of homopolymers that are spinnable and insoluble in water, the polymer blends have been used as substituent and efficient adsorbents for the removal of dyes from an aqueous system. The blend of a polymer containing functional groups with hydrophobic polymer in different ratio plays an important role in improving its hydrophilicity and increasing the adsorption active sites as well as decreasing the cost . One of 2), glutaraldehyde (GA) and trifluoroacetic acid (TFA)) and was used as a nanoadsorbent for the removal of MB dye as shown in 2 was found to be 2230 mg/g, which was higher than that crosslinked by glutaraldehyde and trifluoroacetic acid and the removal efficiency for all remained at 90% after five regeneration cycles as shown in Water-soluble polymers are one of the most important polymers that used in many applications and can also be converted some of them into nanofibers due to their high electrospinnability. However, the use of nanofibers derived from water-soluble polymers such as poly  (PVA) have limitations for use in water treatments due to their instability in aqueous systems. However, this problem can be overcome by creating crosslinking points on the polymer chains to avoid their solubility in water . The cro3−) groups on the surface of PSSNa/PAA@PES and the positively charged MB molecules and vice versa. Dogan et al. synthesized crosslinked polycyclodextrin/polybenzoxazine nanofibers (PolyHPβCD/PolyBA-a) by electrospinning blend of hydroxypropyl-β-cyclodextrin benzoxazine and citric acid followed by thermally cured and used for the removal and separation of MB [The good selectivity towards the adsorption of MB was attributed to the electrostatic attraction between the negatively charged  (PVAc) nanofibers with surface area of 124.5 m2/g using electrospinning and in-situ polymerization process as effective adsorbent for the removal of basic red dyes [3VO4/TiO2 nanofiber composites as an adsorbent for MB removal. The optimum conditions of MB adsorption onto the surface prepared nanofiber composites were dose of 1 g/L, pH 8, contact time of 20 min and temperature of 25 °C [3VO4/TiO2 nanofiber composite was 155.4 mg/g for the removal of MB from an aqueous system.Metal oxides are one of the materials that have been used as an adsorbent for removing various pollutants. However, the application of metal oxide NPs for the adsorption of dyes especially in acidic media is still limited due to the dissolution and chemical corrosion at low pH. The incorporation of metal oxides into polymeric nanofibers can solve the corrosion problem of metals oxides as well as the low mechanical properties of polymer nanofibers. Fard et al. incorporated α-Fered dyes . They prred dyes . The maxof 25 °C . AdditioMetal organic frameworks (MOFs) are a promising class of hybrid material that is constructed from organic linkers and metal–oxide units. MOFs were characterized by high porosity, high surface area, thermal stability, chemical stability and good mechanical properties ,186. MOFPseudomonas aeruginosa, Aeromonas eucrenophila and Clavibacter michiganensis) into cellulose acetate nanofibers by electrospinning for the removal of MB from wastewater [Recently, many studies have been focused on incorporating microorganisms  into polymeric nanofibers as adsorbents for various pollutants ,207,208.stewater . They fostewater . The remstewater . They fostewater . The remstewater . They foCarbon nanofibers (CNFs) have been prepared in the form of mats (webs) from EPNFs by carbonization process and can be used in water treatment. However, the efficiency of pristine CNFs towards removal of ionic pollutants from aqueous solutions is low due to their hydrophobic nature and low dispersion in some solvents as well as their relatively low surface area. Therefore, surface modification is an important approach for enhancing some properties of pristine CNFs and making them more effective towards removal various pollutants. The surface modification of CNMs can be done by different methods, including activation  and functionalization processes by various agents. Recently, Thamer et al. reported the fabrication and functionalization of electrospun carbon nanofibers (ECNFs) as novel nanomaterials for the applications in in water treatment including heavy metal removal  and dyesThe unique properties of EPNFs such as their high surface area-to-volume ratio, and high porosity nominate them for various applications such as environmental applications as water treatment. Moreover, the introduction of functional groups on its surface can enhance their efficiency towards the removal of pollutants from water especially for the removal of cationic and anionic dyes. In this review, we introduced the applications of electrospun polymers nanofibers and their modified ones as nanoadsorbents for the removal of dyes from aqueous solution. The modified EPNFs by blending, crosslinking, functionalization and incorporation processes showed higher efficiency towards the removal of various dyes and stability in aqueous media than the unmodified one due to the increase in the adsorption sites and enhancing mechanical properties. The review is limited for the in vitro reported studies during the last two decades for using EPNFs as new adsorbents for the removal of dyes for aqueous systems. Moreover, the review discussed the most important factors affecting the adsorption capacity of EPNFs in removing dyes, the adsorption mechanism and different modifying methods for enhancing their stability in aqueous media and the mechanical properties as well as their efficiency. On the other hand, the main challenge for the applications of these materials is their use in filed application via treatment of real wastewater, which contains different types of pollutants. So, the future perspective for using these types of materials can be developed in different ways. The first is the in vitro study for their selectivity in removing dyes. The second is the field applications via their use in treatment of real industrial wastewater. The third is to overcome the low production of electrospun polymers nanofibers in the lab scale, especially with adding inorganic materials as nano-fillers. The fourth, application of nonlinear three-parameters isotherm models to describe the adsorption process as well as conducting column study and not being limited to batch adsorption study. Additionally, another consideration that should be taken for future research is the development of modification methods with the aim of enhancing the surface properties of EPNFs , mechanical properties and their stability in aqueous solutions.


As daily lifestyle is closely associated with mental illnesses, diet-based preventive approaches are receiving attention. Supplementation with hop bitter acids such as iso-α-acids (IAA) and mature hop bitter acids (MHBA) improves mood states in healthy older adults. However, the underlying mechanism remains unknown. Since acute oral consumption with IAA increases dopamine levels in hippocampus and improves memory impairment via vagal nerve activation, here we investigated the effects of chronic administration of hop bitter acids on the dopaminergic activity associated with emotional disturbance in a mouse model of repeated social defeat stress (R-SDS). Chronic administration of IAA and MHBA significantly increased dopaminergic activity based on the dopamine metabolite to dopamine ratio in the hippocampus and medial prefrontal cortex following R-SDS. Hippocampal dopaminergic activity was inversely correlated with the level of R-SDS-induced social avoidance with or without IAA administration. Therefore, chronic treatment with hop bitter acids enhances stress resilience-related hippocampal dopaminergic activity. Given the increasing incidence of depression and insufficiency of depression medication, daily life diet-based preventive approaches have been gaining attention. Based on several epidemiological studies, low to moderate alcoholic beverage consumption has mental health benefits. The effects of resveratrol, a red wine ingredient, suppress depression-like behavior in socially-defeated rats and increase dopamine and serotonin levels in the prefrontal cortex (PFC) ,2. HowevAccording to previous studies, the hop-derived bitter compounds, iso-α-acids (IAA), increase hippocampal dopamine levels through the vagal nerves and improve scopolamine-induced memory impairment in an amnesia mouse model . IAA alsVagal activation and non-steroidal anti-inflammatory drug-based treatment have therapeutic effects in patients with depression. Additionally, rodent studies have demonstrated dopamine’s role in stress-induced emotional disturbance. Dopamine exerts effects on motor, emotional, and cognitive functions through multiple brain areas including the medial PFC (mPFC), nucleus accumbens (NAc), caudate-putamen (CPu), and hippocampus. Positron emission tomography imaging studies revealed reduced dopamine transporter binding in the striatum of patients with depression . In rodep < 0.05, dopamine factor and stress factor main effects and dopamine × stress interaction, two-way ANOVA; p = 0.040, designated comparison, Tukey-Kramer post-hoc test) and DOPAC/dopamine  , homovanillic acid (HVA), and 3-methoxytyramine (3-MT) upon dopamine release, the ratio of dopamine metabolites to dopamine reflects the biochemical index of dopaminergic activity. Mice were fed regular chow containing IAAs for 14 days and were subjected to R-SDS . In defep < 0.05, dopamine × stress interaction, two-way ANOVA; p = 0.030, designated comparison, Tukey-Kramer post-hoc test) and DOPAC/dopamine in the hippocampus  and DOPAC/dopamine in the mPFC , with no changes in the other brain areas /dopamine  IAA or MHBA. Each mouse (average body weight is 25 g) intake approximately 4 g of AIN-93M, which contains 2 mg IAA or MHBA (80 mg/kg). According to the calculation of supplementation from mouse to human, a human weighing 60 kg needs to intake 31.8 mg of IAA or MHBA per day. We previously demonstrated that supplementation with 35 mg MHBA improved mood state in a clinical trial [Clinical studies have reported that MHBA supplementation improves the healthy adult mood state. The MHBA group exhibited statistically significant lower anxiety scores in the Profile of Mood States-2 than the placebo group in a randomized, placebo-controlled trial . Here, dal trial . The resThe current study has some limitations. We did not evaluate the involvement of dopamine in R-SDS model mice, so further studies need to evaluate the effects of IAA and MHBA on R-SDS model mice using a dopamine receptor antagonist. In the current study, we measured DA, DOPAC, 3-MT, and HVA as dopamine metabolites, but did not measure the other metabolites such as DOPAL. Since there are no reports on the involvement of these metabolites on emotional disturbance in R-SDS model mice, we did not measure other metabolites, but the recent study report DOPAL as a neurotoxin . To elucSince hop bitter acids are easy and safe to consume daily via beverages, including nonalcoholic beer, the dopaminergic enhancement by these agents might be a practical approach for preventing mood and anxiety disorders. Further clinical studies for the people with high stress or anxiety will help to develop a solution to improve their mood state.w/v) IAA comprising trans-isocohumulone (1.74% w/v), cisisocohumulone (7.61% w/v), trans-isohumulone (3.05% w/v), cis-isohumulone (14.0% w/v), trans-isoadhumulone (0.737% w/v), and cis-isoadhumulone (3.37% w/v) was used to isolate individual IAAs by high-performance liquid chromatography (HPLC), as previously described [a-Acids consist predominantly of 3 congeners: cohumulone, humulone, and adhumulone. During the brewing process, they are each isomerized into two epimeric isomers: cis- and trans-IAAs. A purchased isomerized hop extract stocked in potassium carbonate at 828 mM  with 30.5% . All efforts were made to minimize suffering.Seven-week-old male C57BL/6N and Institute of Cancer Research (ICR) mice (retired from breeding) were purchased from Japan SLC and maintained at Kobe University. On arrival, groups of four mice were housed in a specific pathogen-free, temperature- and humidity-controlled vivarium under a 12-h light/12-h dark cycle  with free access to chow and water. All animal care and use procedures complied with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and were approved by Kobe University Graduate School of Medicine’s Animal Care and Use Committees . All the experiments were prepared and performed from December 2017 to January 2018. Mice were euthanized by placing them in a COw/w) IAAs or MHBAs for 14 days before R-SDS. These mice were then transferred to the home cage of a male ICR mouse for 10 min daily for 10 days. The pairs of defeated and aggressor mice were randomized daily to minimize the variability in aggressiveness of the aggressor mice. After the 10-min defeat episode, the mice were returned to their home cages and isolated until they were subjected to R-SDS the next day. Control mice were transferred to a new cage and allowed to freely explore for 10 min. All data were included in the analyses.Mice were subjected to R-SDS as previously described . Before Following R-SDS, the defeated and control mice were tested using the social interaction test (SIT) ,29. BrieTo evaluate the levels of dopamine and its metabolites in the respective brain regions after R-SDS, the brains were collected immediately after the last R-SDS exposure. They were rapidly removed from decapitated mice and chilled in ice-cold Dulbecco phosphate-buffered saline. They were sliced at 0.5 mm intervals using a mouse brain slicer matrix. Punches  were used to sample tissues from the mPFC, NAc, and CPu. The hippocampus was cut away from a coronal slice of the brain at the bregma level (−3.3 to −3.8 mm) with a surgical knife. The collected tissues were quickly frozen in liquid nitrogen and stored at −80 °C until assay. During the assay, the tissue sample was homogenized in 0.2 M perchloric acid (Wako) containing 100 μM ethylenediaminetetraacetic acid (EDTA)-2Na (Sigma-Aldrich) . The samp < 0.05 was considered statistically significant.The data represent the mean, and the error bars indicate the standard error of the mean (SEM). Data were analyzed using a two-way analysis of variance (ANOVA) followed by Tukey’s multiple comparisons test. Correlation was analyzed using Spearman’s rank correlation. All statistical analyses were performed using GraphPad Prism 7 .


Recently, deep learning has been successfully applied to molecular graph generation. Nevertheless, mitigating the computational complexity, which increases with the number of nodes in a graph, has been a major challenge. This has hindered the application of deep learning-based molecular graph generation to large molecules with many heavy atoms. In this study, we present a molecular graph compression method to alleviate the complexity while maintaining the capability of generating chemically valid and diverse molecular graphs. We designate six small substructural patterns that are prevalent between two atoms in real-world molecules. These relevant substructures in a molecular graph are then converted to edges by regarding them as additional edge features along with the bond types. This reduces the number of nodes significantly without any information loss. Consequently, a generative model can be constructed in a more efficient and scalable manner with large molecules on a compressed graph representation. We demonstrate the effectiveness of the proposed method for molecules with up to 88 heavy atoms using the GuacaMol benchmark. Deep learning has revolutionized the design of novel molecules required for real-world industrial applications. Whereas traditional approaches have mostly been based on human knowledge and intuition, the use of deep learning has enabled the autonomous design of molecules by learning from previously accumulated data –3. Most A major challenge for molecular graph generation is addressing the scalability issue caused by its high computational complexity . The repal world , 6. Consal world , 8 and ZM-dimensional adjacency vectors, where M is set to less than For scalable molecular graph generation, there have been research attempts to alleviate the complexity }O(|V|M) . Goyal et}O(|E|) . Howeverposition . The comFor a more practical application of molecular graph generation, we focus on the latter approach which involves reducing the number of nodes directly in the representation. This study aims to improve the scalability of molecular graph generation to large molecules while maintaining the capability of generating chemically valid and diverse molecular graphs. We present a novel method for the compression of molecular graph representation for scalable molecular graph generation. We designate six small substructural patterns that commonly appear between two heavy atoms in practice and regard their appearances as additional edge features along with the bond types. A molecular graph is compressed by substituting the relevant substructures with new edges. This compression reduces the number of nodes without drastically increasing the number of edge features, making it scalable to large molecules. In addition, the compressed graph can be reconstructed into the original graph without any information loss.i-th heavy atom is represented by a node vector p, whose features indicate the atom type, formal charge, and valence information. An edge corresponding to the connection between the i-th and j-th atoms is represented by an edge vector q, whose features are associated with a bond type. The property vector The conventional graph representation of a molecule is an undirected graph whose nodes and edges correspond to heavy atoms and their bonds in the molecule, respectively. Hydrogen atoms are treated implicitly as node features, and thus, they are not regarded as explicit nodes. Formally, a molecular graph is defined as We compress the graph representation by reducing the number of nodes. We employ six small substructural patterns that commonly appear between two heavy atoms, which are listed in Fig. Formally, we define a compression function With the addition of edge features, the edge vector of compressed graph Figure The main advantages of compressed graph representation are as follows. Firstly, the compressed representation reduces the number of nodes , presented in , on the The architecture of the model is illustrated in Fig.  (MPNNs)  to be inN molecules and their properties, we form a training dataset Given mentclasspt{minimaThe training involves the processing of a graph After training the model, the decoder part We investigated the effectiveness of the proposed method using the GuacaMol distribution-learning benchmark . The traValidity, Uniqueness, and Novelty of 10,000 molecular graphs generated by the model. Validity is the ratio of valid molecular graphs, for which a molecular graph is counted as valid if it can be processed successfully with RDKit. Uniqueness is the ratio of valid graphs that are not duplicates. Novelty is the ratio of valid graphs that are not present in the training dataset. In addition, Kullback-Leibler Divergence (KLD) and Fréchet ChemNet Distance (FCD) are used to evaluate the success of a model in reproducing the distribution of the training dataset.In the benchmark, the performance of a model for generating chemically valid and diverse molecular graphs is evaluated in terms of We used a NAGVAE  trained mentclass2pt{minimmentclasspt{minimaWe employed four SMILES generation models (LSTM , VAE 1616, AAE , and ORGmentclasspt{minimaEach molecular graph in the training dataset was compressed using the compressed graph representation. Figure As evident from the results, the compression function Table From a computational perspective, the use of the compressed representation reduced the computational burden for both the training and inference phases. Considering the complexity As demonstrated by the experimental results, the use of compressed graph representation makes molecular graph generation scalable to large molecular graphs without performance degradation with regard to the generation of chemically valid and diverse molecular graphs. We expect that molecular graph compression will shed some light on improving the efficiency and scalability of other molecular graph generation methods without sacrificing their performance.In this paper, we presented a molecular graph compression method to address the scalability issue of molecular graph generation. We identified six small substructural patterns that commonly appear between atom pairs in real-world molecules. Given a molecular graph, we converted the relevant substructures into new edges by representing them using additional edge features in the compressed graph representation. A generative model was constructed in a more efficient and scalable manner by training the model on the compressed representation. By conducting an experimental investigation using the GuacaMol benchmark, we found that the proposed method reduced the number of nodes significantly without any information loss. The generative model constructed on the compressed representation achieved performance comparable to that of the baseline methods regarding molecular graph generation.Although mitigating the high computational complexity intrinsically imposed on molecular graph generation has been challenging, this work successfully demonstrated that the molecular graph compression approach can effectively alleviate the complexity. We expect that this approach will be more effective with the better identification of data-specific substructural patterns that can be regarded as edge features. The use of the compressed representation contributes to a substantial reduction in the computational cost and memory usage, making it scalable to large molecules. This approach can be applied to other molecular graph generation methods to improve their efficiency and scalability, which merits further investigations.


Head and neck involvement of Kaposi’s sarcoma is rarely encountered, especially for the Mediterranean classic subtype. Here we report a case of non-AIDS related laryngeal Kaposi’s sarcoma in a 77-year-old Tunisian man complaining of 4-month history of hoarseness and dysphagia. The patient underwent exclusive local radiotherapy with a prescription dose of 45 Gy delivered in 1.8 Gy daily fractions. He remained complaint-free for 3 months. First described in 1872 as an “idiopathic pigmented cutaneous sarcoma”, Kaposi´s sarcoma (KS) is a multifocal low grade vascular neoplasm that presents most commonly in cutaneous lesions, typically located on lower extremities. Four epidemiologic-clinical subtypes of KS have been described: African-endemic, epidemic AIDS-related, classic and iatrogenic KS. Although head and neck involvement of AIDS-related KS is frequently encountered, laryngeal primary localisation is uncommon, more specifically in the classic Mediterranean form. Here we report a case of classic laryngeal KS in 77-year-old North African man treated with exclusive low dose radiotherapy.A 77-year-old Tunisian man, with past medical history of hypertension and diabetes, presented to the hospital with 4-month history of dysphagia to solids and hoarseness of voice. No dyspnoea, haemoptysis nor weight loss were reported. His history was significant for tobacco use (56 pack-year). Physical examination found multiple purple indolent macules on the left upper arm. Direct laryngoscopy revealed a massive purplish nodular lesion arising from the left pharyngo-laryngeal wall and infiltrating the left false and true vocal cords, compromising subglottis examination. Multiple biopsies were made. Due to significant oxygen desaturation, tracheostomy was performed without any complications. Histological examination of the biopsy specimen showed a double mesenchymal and vascular proliferation. The mesenchymal component was made of fascicular spindle cells in nuclei bloated with some atypical cytonuclear and few mitotic figures, while the vascular component was made of dilated vessels with a thickened and hyalinized wall . On immuRoutine blood tests showed no significant abnormalities and ELISA examination for HIV-1, HCV, and HBV were negative. Computed tomography (CT) scan revealed a large mass (4.7cmx2.3cm) arising from the left false vocal cord and extending to sub and supraglottic regions, with involvement of thyroid cartilage . No otheKS is an angioproliferative neoplasm characterized by a low-grade potential of malignancy. Although considerable progress in KS knowledge has been made, it remains unclear whether KS is a true malignant tumor or an endothelial cell reactive proliferation. HHV8 identification as the main risk factor for KS development has brought broader insight into understanding the tumor's pathogenesis. KS may manifest in four epidemiologic-clinical forms: African endemic, epidemic AIDS-related, classic and iatrogenic KS . HistopaUnlike the epidemic AIDS-related form, visceral involvement of classic KS is uncommon. More specifically laryngeal localisation is very rare with only few cases described in the literature -4. SymptLaryngeal involvement of KS is very rare, especially for the Mediterranean classic subtype. Low dose radiotherapy can offer significant symptom-relief and local regression and should be considered in the management of this localisation. Further research on targeted therapies for HHV-8 inhibition is needed, as it may provide a promising treatment for KS.


To compare the results obtained with two threshold strategies of visual field assessment: Humphrey SITA Fast (SFA) (Carl Zeiss Meditec) and PTS 2000 Advanced Threshold (ADV) (Optopol Technology) in healthy subjects and patients with glaucoma.  The study sample comprised of 53 healthy volunteers and 69 patients with glaucoma. One eye of each patient was examined with the SFA and ADV strategies. The quantitative comparisons of test duration and global indices were made using correlation coefficients. The sensitivity and specificity of the algorithms were evaluated based on the GHT results and the adjusted Anderson–Patella (A&P) criteria. SFA-MSADV) in healthy subjects and 1.00 ± 1.92 dB (MSSFA-MSADV) in patients with glaucoma. The MD index of ADV tests was lower than the SFA in the healthy (−0.74 ± 1.09 dB) (MSSFA-MSADV) and glaucoma group (−0.85 ± 2.19 dB) (MSSFA-MSADV). The mean differences in PSD values determined using both methods were −0.86 ± 0.67 dB (PSDSFA-PSDADV) and −0.53 ± 1.48 dB (PSDSFA-PSDADV) in healthy subjects and patients with glaucoma, respectively. Analysis of receiver operating characteristic curves built from MD and PSD indices show bigger area under curve in SFA than in ADV . The GHT-based sensitivity and specificity for the ADV strategy were 92.75% and 77.36%, respectively, as compared to 92.75% and 90.57%, respectively, for the SFA strategy.  The ADV test duration was shorter both in healthy subjects (by 5%) and patients with glaucoma (by 18%). The mean differences in MS values between the SFA and the ADV strategies were 1.06 ± 1.13 dB (MS Both SFA and ADV enable effective identification of glaucomatous defects within 5 minutes. The ADV strategy, however, is significantly faster. The correlation between the global indices of SFA and ADV is very high. Both strategies offer very high sensitivity when using both GHT and A&P criteria. In the age of rapid development of OCT-based diagnostic instruments in ophthalmology, the automated perimetry is still the fundamental method of visual field assessment. It provides not only an estimation of retinal sensitivity but can also confirm the effect of all pathological findings demonstrated using other diagnostic tests on the patient's functional vision. However, perimetry is a subjective method, and as such, it is totally dependent on patient cooperation. Subjects with poor reliability of responses will produce unreliable results. It was proven that patient fatigue during the test is one of the key factors, which affect the reliability of its result. One of the main goals of researchers who worked on automation of perimetry back in the 1970s was to optimize the threshold evaluation strategy . The resThe aim of the paper is to compare the results obtained with HFA SFA and PTS ADV strategies in healthy volunteers and subjects with glaucoma. The sensitivity and specificity of both tests in detecting visual defects in patients with glaucoma were also assessed.p < 0.0001).The study group comprised of 135 healthy volunteers and glaucoma patients recruited from ophthalmic clinic. None had diabetes, cataract, and corneal or retinal disease which could affect test results. Patients were classified as healthy when they had (1) no suspicious disc changes, (2) no family history of glaucoma, (3) normal intraocular pressure, (4) refractive error below 5 dioptres sphere and 3 dioptres cylinder, and (5) best corrected visual acuity of 0.5 or better. All participants additionally had visual field performed twice within 2 weeks prior to study commencement. The glaucoma group was selected based on the following criteria: (1) patients with glaucomatous disc changes and intraocular pressure >21 mmHg, (2) refractive error below 5 dioptres sphere and 3 dioptres cylinder, (3) best corrected visual acuity of 0.5 or better, and (4) previous experience of automated perimetry. One eye of each subject was enrolled in the study. If both eyes were eligible, a random choice was made. Each patient underwent a series of two tests on HFA II 750i and Optopol PTS 2000 perimeters. Both devices utilized the gold standard testing parameters: Goldman stimulus of size III, white colour, maximum intensity of 10000 asb, 300 mm aspherical bowl, and background illumination of 31.5 asb. The default duration of the stimulus exposure was 200 ms in HFA II 750i and 250 ms in PTS 2000. The HFA device used the SFA strategy whereas the PTS 2000 used the ADV strategy. All tests were performed on 24-2 test field, without fovea and short-fluctuation (SF) testing. There was a 10- minute break between the tests within the series, and the order of the tests within the series was randomized to avoid the fatigue effect bias. The appropriate spectacle correction was used for all tests. The reliability of the tests was evaluated with use of false-positive (FP), false-negative (FN), and blind-spot monitoring. The HFA SFA results were considered unreliable if any of FP, FN, and fixation loses (FL) error indexes exceeded 25%. The PTS ADV results were considered unreliable, if more than one error index exceeded 25%. The results were included in the analysis only if both test results for a given eye were reliable. Thus, 122 eyes were selected for further assessment. The healthy group contained 53 healthy eyes , whereas the glaucoma group consisted of 69 glaucomatous eyes . The mean age of glaucoma patients was significantly higher than that of the healthy subjects  maintaining information about raw sensitivity value at all test locations except 2 points within the blind spot area. The following information was extracted: mean test duration, mean sensitivity (MS) index, mean difference between the SFA MS and ADV MS, root mean square (RMS) of differences between threshold estimate in the SFA and ADV strategies, mean defect (MD) index, mean difference between the SFA MD and ADV MD, pattern standard deviation (PSD) index, mean difference between SFA PSD and ADV PSD, visual field index (VFI)/visual quality index (VQi), mean difference between VFI and VQi, and the Glaucoma Hemifield Test (GHT) result. The correlation between the SFA and ADV global indices was then analysed. Each result was also assigned the Anderson–Patella (A&P) classification index  depending on how many criteria it met . The firThe SITA algorithm is based on the Bayesian posterior probability distribution functions. In its core, SITA uses both staircase and maximum-likelihood threshold procedures. For each test, there are two Bayesian posterior probability distributions calculated and constantly updated throughout the test, that is, normal and glaucomatous. The initial models are built based on the prior knowledge of age-corrected normal thresholds and random intersubject visual field variability , 24. TheThe ADV algorithm is divided into 4 consecutive virtual stages . The poiThe summary of visual field indices values  is presented in p < 0.0053) and glaucoma patients (p < 0.0001). The mean test duration was significantly longer in glaucoma patients, both with SFA (p < 0.0001) and ADV (p < 0.0001). There was no correlation between patient age and the duration of SFA  or ADV  test in healthy subjects, as well as in glaucoma patients   and no correlation in the healthy group   .p < 0.0001) and glaucoma group (p < 0.0001) (SFA-MSADV) was 1.06 ± 1.13 dB and 1.00 ± 1.92 dB in the healthy and glaucoma group, respectively. This number did not differ significantly between the healthy and glaucoma group (p=0.8507). The MS index difference between SFA and ADV was systematic and independent of patient condition. There was a moderate negative correlation between patient age and MS in SFA  and ADV  in the healthy group, but no correlation between MS and patient age in SFA  and ADV  in the glaucoma group  and a very strong such correlation in the glaucoma group   . The mea1.98 dB) . The BlaSFA-RMSADV) for all tested locations was 3.01 ± 0.84 dB in healthy subjects and 6.36 ± 2.07 dB in glaucomatous patients. The mean RMS was significantly higher in glaucomatous eyes than in healthy eyes (p < 0.0001). There was no correlation between patient age and RMS both in the healthy  and glaucoma group . The RMS value analysis with respect to test point locations in the healthy group showed that the highest error is at points adjacent to the blind spot area . Inspection of test results showed that this point was often at the sharp boundary between normal and depressed visual fields in advanced glaucoma cases and the estimated threshold fluctuated between the tests. The mean RMS of differences in sensitivity values between SFA and ADV (RMSpot area . The incpot area . There wp=0.0021) and glaucomatous group (p < 0.0001) (SFA-MDADV) compared to SFA MD in the healthy group and by −0.74 ± 1.09 dB (MDSFA-MDADV) in the glaucomatous group. The differences were not significant (p=0.7452). There was no correlation between patient age and MD in SFA  or MD in ADV  in the healthy or glaucoma group   and a strong correlation in the healthy group   . The dif0.84 dB) . The Bla0.84 dB) . The meap < 0.0001) and glaucoma group (p=0.0039) (SFA-PSDADV) and lower than in the SFA test in glaucoma patients with the difference of −0.53 ± 1.48 dB (PSDSFA-PSDADV). The differences were significant (p < 0.0001). There was no correlation between patient age and PSD in SFA  and in ADV  in the healthy group, as well as between patient age and PSD in SFA  and in ADV  in the glaucoma group  but no such correlation in the healthy group   . The PSD Figures . There w0.37 dB) . The BlaAnalysis of ROC curve built from MD index shows bigger Area Under Curve (AUC) in SFA than in ADV (0.983 vs.0.968) Figures . The optp < 0.0001) but no difference in the glaucoma group (p=0.1036) (p=0.9009). There was no correlation between age and VFI  or age and VQi  in the healthy group. Similarly, there was no correlation between age and VFI  or age and VQi  in the glaucoma group  but only a weak correlation in the healthy group   . The VQi Figures . There w=0.0133) .In the group of 53 healthy eyes, 37 SFA and 39 ADV assessments yielded a normal GHT result. Eleven SFA and only 2 ADV assessments were classified as a borderline GHT. The false-positive result, that is, GHT outside normal limits, was assigned to 5 SFA and 12 ADV results. When specificity was evaluated based on the normal and borderline GHT result considered a healthy outcome, the specificity of the SFA and ADV strategies was 90.57% and 77.36%, respectively. However, with the exclusion of the borderline GHT result as a healthy outcome, this value dropped to 69.81% and 73.58%, respectively. In the group of 69 glaucomatous eyes, 2 SFA and 3 ADV assessments yielded a false-negative result . Three SFA and none of ADV assessments were classified as GHT borderline. The outside normal limits GHT was assigned to 64 SFA and 64 ADV results. When sensitivity was evaluated based on the outside normal limits GHT result as indicative of glaucoma, the sensitivity of the SFA and ADV strategies was 92.75% and 92.75%, respectively. However, with the inclusion of the borderline GHT result as indicative of glaucoma, the sensitivity of the SFA improved to 97.10% and the sensitivity of the ADV remained unchanged at 92.75%.In the group of 53 healthy eyes, 36 SFA and 37 ADV assessments met none of the 2 A&P criteria. There were 8 SFA and 6 ADV assessments, which met a single A&P criterion. The false-positive result (2 out of 2 A&P criteria met) was found in 9 SFA and 10 ADV assessments. When specificity was evaluated based on 0/2 A&P or 1/2 A&P criteria met considered a healthy outcome, the specificity of the SFA and ADV strategies was 83.02% and 81.13%, respectively. However, with the exclusion of 1/2 A&P criterion met as a healthy outcome, this value dropped to 67.92% and 69.81%, respectively. In the group of 69 glaucomatous eyes, 1 SFA and 4 ADV assessments yielded the false negative result (none of A&P criteria met). There were only 2 SFA and 9 ADV assessments which met a single A&P criterion. There were 66 SFA and 56 ADV assessments which met both A&P. When sensitivity was evaluated based on all A&P criteria met as indicative of glaucoma, the sensitivity of the SFA and ADV was 95.65% and 81.16%, respectively. However, with the inclusion of only one A&P criterion met as indicative of glaucoma, this value increased to 98.55% and 94.20%, respectively. All three A&P criteria, including the PSD probability <5%, were met in the SFA strategy by 64 patients from the glaucoma group. Using all 3 A&P criteria as indicative of glaucoma would increase specificity of SFA to 88.68% whist decreasing its sensitivity to 92.75%Both HFA II 750i and Optopol PTS 2000 offer gold standard parameters of visual field testing conditions. The equality in technical specification implies that the results obtained with one perimeter could be compared to those from another. Hence, one can assume that the differences demonstrated in this study solely originate from algorithm differences in SFA and ADV testing strategies.The main goal of the SFA and ADV strategies is to minimize test duration while maintaining clinical capabilities of threshold testing. The previous studies showed that SFA can reduce test duration by 66% compared to the full threshold . In thisA comparison of MS values obtained with SFA and ADV shows that, on average, the values obtained with the SFA are higher than those obtained with the ADV. This difference can be explained by the fact that the SFA strategy sets the final threshold at intensity values related to the peak of the probability distribution function. The peak of the function denotes intensity value with the largest probability to be a real threshold . In contr = 0.95, p < 0.0001, S = 1.98 dB) between the MS values in ADV and SFA in patients with glaucoma. The MS is mainly affected by the testing algorithm and test parameters, such as stimulus intensity, background illumination, and stimulus size. Thus, if the parameters are matched and the testing algorithms are similar, we can expect to have a linear relation between the MS indices obtained with the two devices. This correlation was weaker  in healthy subjects than in patients with glaucoma, in whom a higher variability of MS values assessed with the ADV than with the SFA was observed. This can be explained by the properties of the SITA algorithm which offers a lower variability of results for sensitivities above 20 dB than the full threshold, which is a noninteractive thresholding algorithm [S = 0.91 dB was calculated for the healthy group.There was a very strong correlation . However, in the glaucoma group, this effect is diminished. The SFA “snapping” is not that significant here, as the threshold values are already outside the normal range and the estimates are shifted towards lower intensities. In the glaucoma group, the mean difference in PSD indices between SFA and ADV is 0.53 dB. There is a very strong correlation between these values, confirmed by a high correlation coefficient  and the trend line with a slope close to 1.The PSD index describes an irregularity of visual field sensitivities. In our study, mean PSD values obtained with the ADV strategy in healthy subjects were slightly higher than those obtained with the SFA strategy. This can be explained by the higher variability of threshold values around the normal intensity in the ADV strategy than in the SFA. In the latter, one exposure is sufficient for some points to get the final threshold estimate. If the exposed brightness is close to the expected threshold estimate and the error-related factor is acceptable, the final threshold is set at that threshold estimate. As a result, the values close to the age norm are “snapped” to actual normative values, which reduces variability and irregularity. With the ADV strategy, on the other hand, the values are displayed, which the patient was actually exposed to and confirmed. Thus, there is no correlation between PSD assessed with ADV and SFA in the healthy group (One of the latest global indices introduced in visual field analysis in HFA devices is VFI . It is iThe sensitivity and specificity assessment, based on the GHT only, was conducted two-fold. In the first instance, a result was interpreted as indicative of glaucoma, if the GHT was outside normal limits. All borderline and normal results were assigned to the healthy group. Assessed based on a GHT outside normal limits result, the sensitivity and specificity of SFA were similar to those reported in previous studies . In the The criteria proposed by A&P are widely used to classify visual fields as normal or glaucomatous.  The sensDue to the differences between algorithms, the ADV strategy produces different results to those of the SFA. Since ADV is more sensitive to patient invalid responses in the normal range of sensitivities, the visual field can be classified as outside normal limits. At the same time, the SFA strategy adjusts the patient result to age norm and, therefore, keeps healthy patient visual field closer to it. The ADV strategy in its core is more similar to the HFA full threshold test as its sensitivity results have values that have been tested and have evoked a response. The SFA due to its roots in statistics and probability theory gives results which are not always measured but are the most probable. This makes it less prone to small fluctuations and patient errors and gives the SFA a better measure of specificity based on the GHT criterion. The problem of high variability of sensitivity results due to patient response inconsistency has been known and addressed in the past , 3. One The differences between the two strategies lose their importance when evaluating glaucomatous fields because the normal variability of evaluated sensitivities within the glaucoma-affected regions is much higher than in healthy regions. The differences between strategies in glaucomatous fields are then less noticeable and seem negligible. This can be confirmed by the high sensitivity of both strategies when using both GHT and A&P criteria. Therefore, in light of that mentioned above, the further study could aim to directly compare SFA and ADV with full threshold strategy. This will help to determine which strategy provides closer estimations of the full threshold sensitivities. Another aspect that could be covered in further studies is the results reproducibility. The test with repeated examinations of the same patients may give the answer whether the ADV strategy is actually prone to fluctuations more than statistically supported SFA. Finally, it would be also beneficial to compare the ADV to the SFR. The latter strategy was not available yet when the study was carried out.Both SFA and ADV are fast strategies which enable successful identification of glaucomatous defects. Our study has demonstrated that both algorithms offer the same high sensitivity of 92.5% which has not been compromised by test duration. Both strategies enabled effective identification of glaucomatous defect within 5 minutes with the ADV, where the assessment was shorter by 1 minute, being the fastest strategy in the study. However, the ADV strategy has one shortcoming compared to the SFA. Its results are not based on statistical data; therefore, the test-retest variability cannot be reduced in healthy patients, as it is carried out with the SFA. As a result, the ADV algorithm offers lower specificity when evaluated using the specificity criteria designed for SITA algorithms and, thus, requires more retests to make certain diagnosis.


It was found that the aging process has detached Oleylamine from QD surface and as a consequence In2S3 QD embedded Oleylamine–Acetone aggregates was obtained. When this In2S3 QD embedded molecular cluster system was used as an active layer in a photo conductor device then a maximum photo current value of the order of milli Ampere was obtained. The surfactant molecules normally inhibit the charge transport between QD systems and as a result it is always problematic to have the functional molecules in the QD based transport devices. Our approach has a solution to this problem and the present paper discusses the outcome of the results in detail.Blue emission giving nanoscale molecular clusters of Oleylamine–Acetone system was formed by an aging assisted hydrogen bond formation between the interacting molecular systems, at room temperature. The as-formed nanoscale molecular clusters were found to be self-assembled into flower-like aggregates and shifted the emission wavelength to red colour depicting an exciton delocalization in the aggregate system. Interestingly aging process has also produced imine type binding between Oleylamine and Acetone due to the condensation reaction. The experimental conditions and formation mechanism of hydrogen bond assisted Oleylamine–Acetone molecular aggregates and imine bond assisted Oleylamine–Acetone is elaborated in this paper in a systematic experimental approach with suitable theory. Finally we have introduced this Acetone assisted aging process in In Michael Kasha, American photochemist has clearly explained the concept of photophysics in molecular aggregates. According to kasha’s rule, molecular aggregates can be classified into two types such as H-aggregates and J-aggregates8. H-aggregate is the aggregate in which transition dipoles of neighbouring molecules are aligned in a parallel fashion, exhibiting hypsochromic shift in the absorption spectrum compared to monomer absorption10. On the other hand, when transition dipoles of neighbouring molecules are aligned in a head to tail manner, it exhibits bathochromic shift in absorption spectrum compared to monomer absorption which is coined as J-aggregates12. Packing of molecules to form aggregate is highly related to intermolecular interactions between the molecules. The intermolecular interactions in the form of magnetic dipole moment, electric dipole moment, pi–pi stacking, halogen13 or hydrogen bonding allows ordered structure of molecules14. Among which hydrogen bonding triggered self-assembly is very interesting one20. High boiling point of water arises from OH…HO type hydrogen bond in the system21. NH…O=C type hydrogen bond exist in DNA system make them semiconducting23. Hydrogen bonded pigment indigo is a very good organic semiconductor. NH…O=C type hydrogen bond with neighbouring molecules along one particular crystal axis and π-stacking along perpendicular direction leads to higher mobility in indigo. Optical absorption spectra of most of the hydrogen bonded pigments undergo extensive bathochromic shift from dilute solution to the solid state. Hydrogen bond enhanced delocalization effect26 was briefly explained in ϒ-quinacridone27. This pigment is used as an active layer in photovoltaic device and shows considerable external quantum efficiency of nearly 10%. Herewith we have illustrated the NH…O=C type hydrogen bond interaction found between Oleylamine and Acetone and studied their self-assembling nature upon aging for the first time.The study on “Molecular aggregates”30 is a well-known capping ligand31 used for the synthesis of various metal and semiconducting nanomaterials33. This molecule has received much research attention in the area of phosphine-free growth of colloidal quantum dots35. Oleylamine can be used as a passivating layer in silicon solar cell to enhance the device efficiency36. Doping of Self-assembled Oleylamine networks37 in MoS2 transistor can increases the carrier concentration from 0.7 × 1012 cm−2 to 1.9 × 1013 cm−2. Oleylamine belongs to the family of primary aliphatic amines and the chemical structure of Oleylamine is similar to that of Oeic acid except the end group COOH (the end group is NH2 in Oleylamine). It is well known that amine–carbonyl type hydrogen bonding is much studied in pigments like Indigo, tyrian purple, quinacridone, epindolidione and biomolecules such as DNA and proteins16. Because Oleylamine contains two hydrogen atoms covalently bonded to the nitrogen atom, it can easily form hydrogen bond with neighbouring molecules. With this basic knowledge, here we have chosen carbonyl group containing molecule Acetone and amine group containing molecule Oleylamine and studied their possibility to form amine–carbonyl type intermolecular hydrogen bonding interaction. Interestingly, aging assisted formation of hydrogen bond in the Oleylamine–Acetone was found at room temperature and that leads to the formation of nanoscale molecular clusters and their flower like self-assemblies. The present paper gives an insight into the formation of such a structures and their application in a systematic approach. Interestingly we have also observed the room temperature formation of imine type interaction between Oleylamine and Acetone molecules during the aging process and that was due to the condensation reaction between Oleylamine and Acetone across the interface between solute and solvent. This process has converted Oleylamine into Oleylimine. By optimizing the ratio between Oleylamine and Acetone an interface free condition was set to avoid the formation of Oleylimine and as a result hydrogen bond assisted molecular cluster/aggregates were only formed.Oleylamine2S3 quantum dot system prepared with Oleylamine as surfactant molecule, and this is in order to understand the consequences of aging process in photo current generation in In2S3 QD system. Interestingly the aging process has removed the Oleylamine surfactant molecules from In2S3 QDs. As evidence slightly size enlarged In2S3 QDs were found to be coexisting with Oleylamine–Acetone molecular cluster system. It was found that the molecular cluster system worked as conducting matrix, and thus helped to improve the overall photo current generation to few milli amps. In the present paper the formation conditions of hydrogen bond assisted Oleylamine–Acetone molecular clusters/aggregates and covalent interactions between the molecules will be discussed first and followed by In2S3 QD preparation/device results will be discussed.Nanoscale cluster to macro scale aggregates and their reversible process was controlled by changing the dilution level of the cluster system and as a result rapid reversible photoluminescence behavior was also noticed. This paper discusses about the reversible emission behavior of the molecular system and the formation of mechanism of the molecular clusters in detail. Finally we have introduced this strategy, that is, Acetone assisted aging process in InOleylamine  purchased from Aldrich and Acetone (99%) obtained from Loba chemicals were used in this study.A 5 ml of Oleylamine mixed with 2 ml of Acetone stored in centrifuge tubes initially looked like transparent in nature and after ten minutes it was converted into whitish cloud solution. Then the solution was separated into two layers when the aging process proceeds for four weeks. The upper part seems to be yellowish in colour and the lower part seems to be colourless. When we excite the sample with UV laser, then we have attained dual colour emission from the sample in such a manner that the upper part looks yellow in colour and the lower part looks blue in colour.A 5 ml of Oleylamine mixed with 10 ml of Acetone exhibited transparent colour during the day of mixing, then every week its colour changed from pale yellow to dark red after one month. Almost similar experiments were conducted with different ratio as mentioned in the main text.3+ and S2− ions respectively. Dodecanthiol  and Oleylamine  were used for the capping purpose. Acetone  was used for aging study. A 0.001 mol of indium chloride was dissolved in 1-Dodecanthiol and stirred under Argon atmosphere at 110 °C for half an hour. Elemental Sulfur was dissolved in Oleylamine and stirred under vacuum at 90 °C for half an hour. After that elemental sulfur solution was quickly injected into indium chloride solution and mixed under Argon atmosphere for 20 min to grow indium sulfide quantum dots. As obtained quantum dots were purified by means of using equimolar ratio of Hexane (Solvent) and Methanol (Antisolvent) under centrifugation at 5000 rpm for 30 min. As prepared Oleylamine and 1-Dodecanthiol capped blue emitting In2S3 quantum dots were dissolved in Acetone and kept under aging for 1 month.Indium Chloride , Elemental Sulfur  were used as a source material for In18H35NH2) obtained from Sigma Aldrich was mixed with 10 ml Acetone (CH3COCH3) and the resulting sample’s optical absorption and emission spectra were recorded before aging. The absorption and emission38 maximum were at 350 nm and 410 nm respectively for this sample as shown in Fig. 39. By varying the size of the quantum dots, quantum confinement level was controlled to tune different emission wavelengths. In our case the samples are not QDs, but molecular solution and therefore the possibility of forming molecular clusters/aggregates could be the main reason behind the observed emission shift. In the case of molecular system, aggregation induced emission42 (AIE) and aggregation caused quenching (ACQ) are the two important phenomenon that occur in many of the organic molecules. Aggregation of fluorophore can yield any of the following emission characteristics in comparison to that of its diluted state (i) Quenching of fluorescence intensity. (ii) Enhancement of fluorescence intensity and unchanged fluorescence intensity. If the fluorescence intensity of aggregates is enhanced in comparison to that of dilution state then the process is called aggregation induced emission46. In contrast, if the fluorescence intensity of aggregates is reduced in comparison to that of dilution state then the process is called aggregation caused quenching. Some of the fluorophores exhibited aggregation induced redshifted emission (AIRSE)47. Herewith we have obtained the aggregation induced redshifted emission at first through aging process and a rapid dilution assisted reversible blue shifted emission. The observed photoluminescence behaviour clearly indicates a fact that there is a possibility of forming some types of clusters/aggregates and dis-aggregates. In order to find out the correlation between the change in the emission wavelength and micro structure of the samples, we have subjected the samples to HRTEM analysis  as shown in Fig. 48 between hydrogen in the Oleylamine50 and oxygen in the Acetone. Figure In order to know about the vibrational level changes upon the formation of nanoscale molecular clusters and their self-assemblies we have subjected the samples to Fourier transform infrared spectroscopy analysis. Figure 52. The Oleylamine–Acetone sample at the time of mixing has shown the respective samples Raman modes as in Figure 53  formed at the bottom of the beaker during the condensation reaction reaches the top portion of the solution and become responsible for the FTIR mode at 1662 cm−1. Thus from overall experimental observations we understand the following facts. At a critical ratio between the solute and solvent, Oleylimine formation is not effective, instead hydrogen bond mediated Oleylamine–Acetone molecular clusters and aggregates are preferentially formed. It means that when we are taking the solute and solvent at the relative critical concentration then hydrogen bond formation favorably taking place.When the samples having two regions were seen through UV light excitation, interestingly we have noticed two different emission colours as shown in Fig. 2) ending and Acetone has open oxygen atom (–C=O), hydrogen bonding could possibly happen between those molecules. Possibilities of other non-covalent interactions in other sites of molecules are seems to be low. Hence we carried out quantum chemical analysis on probable hydrogen bonding sites where electronegative atoms and hydrogen atoms are co-existent. Figure 56, liquid–air interface assisted peptide bond formation57 are the best examples for the conversion of monomers into a big molecule. At the interface when monomer molecules try to diffuse from one region to other there is a high possibility to have interaction between them and therefore monomer becomes large sized molecules. Here we believe that when monomer molecules (Oleylamine and Acetone) diffuse from one part of the liquid to other there is a close interaction between them leading to the formation of Oleylimine, leaving Water molecules as byproduct. Therefore from overall experimental/theoretical studies we come to a conclusion that the hydrogen bond type chemical interaction between Acetone and Oleylamine is due to the formation of micelle structure and relative stronger solute–solvent and solute–solute interaction between the molecules. On the other hand Oleylimine is formed due to the interfacial effect and that happens at a different ratio between solute–solvent mixing. The photographic image of of different dilutions of Oleylamine–Acetone aged samples under UV laser illumination as shown in Fig. Theoretical work also has been conducted in order to understand the formation of hydrogen bond and its stability in Oleylamine–Acetone molecular system, through quantum chemical calculations. Theoretical emission spectrum of Oleylamine were obtained in Air and Acetone solvent medium and this is to understand the environmental effect on Oleylamine emission spectra. Figure 2S3 quantum dot samples, as an example system. First we have prepared Oleylamine and 1-Dodecanthiol capped blue emitting In2S3 QDs by Hot Injection Technique . Then the QDs were dissolved in an optimized Acetone concentration and kept under room temperature aging process for one month. Figure 2S3 QD system, which shows the clustered type QDs with an average size of 3 nm. In contrast to this as prepared sample’s HRTEM image, the aged sample’s HRTEM image has shown a different morphology, consisting of In2S3 QDs with relatively larger size (average size: 19 nm) and as well as Oleylamine–Acetone molecular clusters, as we have seen previously. The size distribution corresponding to larger sized In2S3 QD is given in the 2S3 QDs were found to embedded in the Oleylamine–Acetone molecular aggregate matrix as shown in Fig. 2S3 QDs and that leads to the detachment of Oleylamine molecules from QD surface and as a consequence there is an increase in QD size. In the absence of sufficient surface coverage smaller sized In2S3 QDs started to grow into larger sized QD system is the reason for this observation. The optical absorption and emission spectra were recorded from the aged sample and compared it with the data of as prepared samples. Interestingly we have seen a shift in the emission peak position from blue to red wavelength, as noticed previously in the molecular aggregate samples. This shift could be due to the possible energy transfer interaction between blue emission giving In2S3 QD and red emitting Oleylamine–Acetone cluster system. As the broad absorption band position of the molecular cluster has overlapped with the emission maximum of blue emitting In2S3 QD, there is a high possibility to have energy transfer interaction between In2S3 QD and molecular cluster system. The presence of In2S3 QD in the matrix of molecular cluster thus enable the transfer of photoexcited charge carriers from In2S3 QD to molecular system. To use this advantage in the photo current generation, a photo current device was constructed using the In2S3 QD/Oleylamine–Acetone molecular aggregate hybrid system as an active layer. For comparison purpose devices were also constructed with In2S3 QD free molecular cluster sample as an active layer as well.Since Oleylamine is an important surfactant molecule used to prepare size controlled quantum dots, Acetone assisted aging process was done in In2S3 QD aged sample was used as an active material then we have noticed a high magnitude photocurrent in mA range as shown in Fig. 2S3 QD un-aged samples photocurrent data are also given in Fig. 2S3 QD in the matrix of Oleylamine–Acetone aggregates pumps in more photo generated charge carriers into the molecular cluster system and therefore a high magnitude photocurrent is possible in the hybrid sample. Since the as prepared aggregates are J-type with head to tail dipole arrangement and as this arrangement is helping to delocalize the charge carriers, the photo excited charge carriers transferred from In2S3 QD can be easily conducted through the molecular aggregates, therefore, high magnitude photocurrent is possible. From the comparison of all of the photocurrent data, it is concluded that there is an overall increase in the photocurrent magnitude when aged In2S3 QD sample is used and which supported our claim that the photoexcited charges are transferred to molecular cluster system through energy transfer interaction. Since, most of preparation experiments of colloidal QDs are done by organic surfactants/ligands such as Oleylamine, Oleic acid and tri-octyl phosphine oxide, which are introduced during colloidal QDs synthetic procedures to control nucleation and growth, their presence in the device structure has some disadvantageous effect on the device performance. For example, these ligands on the colloidal QDs surface are usually electrically insulating and prohibits the hopping of photo induced excited charge carriers from one QD to other and as a result, a less number of photo excited charge carrier reaches to electrode. Hence therefore, the replacement of bulky surfactants are essential to increase the charge carrier transport within the colloidal QDs or from QDs to another nanostructured system (for eg: to TiO2 electrode) for an improved photocurrent generation. It is therefore various efforts have been taken to post synthesis replacement of capping ligands with short chain molecules or mono atomic ligands  to form interconnected QD network structure. Here we have used a different approach to remove the surfactant molecule (Oleylamine) from In2S3 QD surface by aging assisted cluster formation method. Interestingly the as formed molecular aggregates are found to be acting as a conducting platform to transport the photo excited charge carriers from In2S3 QD system and enhanced photocurrent is generated. It is therefore believed that our approach can solve the problem associated with the removal of surfactant from QD system, in the future.The structure of the photocurrent device fabricated using the as formed cluster solutions as photoactive material and the relative energy level diagram are shown in Fig. . The devIn conclusion, through experimental and quantum chemical calculation results we have realized hydrogen bond mediated heterostructure type molecular cluster formation and their aggregation, resulting of red shift in the emission wavelength for the first time. Aging assisted formation of NH…O=C type hydrogen bond between Oleylamine and Acetone leads to the formation of nanoscale molecular clusters. Once the nanoscale molecular clusters were formed then the formation of flower like aggregates and their dissociation as well as reformation were rapidly occurred by means of controlling the dilution level of flower like aggregates in Acetone. Dissociation and reformation of flower like aggregates leads to the red to blue and blue to red shift in emission characteristics in a rapid manner. The sensitiveness of the ratio between solute/solvent in deciding covalent or non-covalent hydrogen bond type interactions were elaborated in Oleylamine–Acetone molecular system. Covalent interaction between Oleylamine and Acetone was possible due to the formation of liquid–liquid interface between molecular cluster and non-cluster solution, followed by diffusion of monomers through interface. Further high current giving photoconductive device was also realized from the molecular cluster/aggregate system. When this implication (molecular cluster formation) was introduced in a real quantum dot system, there we noticed an further increase in the photocurrent generation.Supplementary Information.