Lactate is present in sweat at high concentrations, being a metabolite of high interest in sport science and medicine. Therefore, the potential to determine lactate concentrations in physiological fluids, at the point of need with minimal invasiveness, is very valuable. In this work, the synthesis and performance of an alginate bead biosystem was investigated. Artificial sweat with different lactate concentrations was used as a proof of concept. The lactate detection was based on a colorimetric assay and an image analysis method using lactate oxidase, horseradish peroxidase and tetramethyl benzidine as the reaction mix. Lactate in artificial sweat was detected with a R² = 0.9907 in a linear range from 10 mM to 100 mM, with a limit of detection of 6.4 mM and a limit of quantification of 21.2 mM. Real sweat samples were used as a proof of concept to test the performance of the biosystem, obtaining a lactate concentration of 48 ± 3 mM. This novel sensing configuration, using alginate beads, gives a fast and reliable method for lactate sensing, which could be integrated into more complex analytical systems. Sweat is an aqueous solution that contains a great variety of compounds, such as NaCl, lactate , nitrogeThe high amount of physiological information contained in sweat, together with its accessibility in a non-invasive way, highlights the potential of sweat as an emerging alternative to standard blood analysis. Thereby, the analysis of sweat could provide an accurate insight into the physiological condition of the body , but also a way of measuring body dehydration . In factIn particular, lactate, which can be found in all physiological fluids, including sweat, is an important biomarker of fatigue and an indicative of restricted oxygen levels since it is a product of the anaerobic metabolism that takes place during the performance of intense exercise. Thereby, it is a metabolite of high interest in sport science and medicine, which can be used to keep track of the performance of athletes and to design a personalised training plan for each individual. In addition, it can be used as a diagnostic tool for disorders such as pressure ischemia, characterised by high levels of lactate . HoweverL-guluronate and β-D-mannuronate residues arranged in linear copolymer blocks [One of the possible biomaterials that could be employed to this end is alginate, a natural anionic polymer that can be found in brown algae and is composed of 1,4-linked α-r blocks . The bior blocks ,22,23.2+ and Ba2+, which bind the guluronate units allowing the cross-linking of the linear chains. These alginate hydrogels can be applied, for example, to alginate encapsulation of transplanted pancreatic islet cells in patients with type I diabetes as a way of protecting against a possible immune response of the host [2+ capable of effectively detecting Co2+ in aqueous solutions as an environmental analysis tool. Recently, our group has developed an alginate/titanium dioxide nanotubes nanocomposite for the detection of lactate and glucose [Alginate hydrogels are formed by cross-linking the linear polysaccharide chains, thus creating a 3D network capable of retaining a high amount of water. The typical methods for alginate cross-linking are based on physical and chemical approaches: covalent cross-linking by the addition of a reagent that promotes covalent bonds between the alginate chains, thermal gelation based on temperature changes, cell cross-linking by adding cell adhesion ligands to the alginate and ionic cross-linking . This lathe host . Despitethe host  developethe host  fabricat glucose .The interest of using these types of biomarkers in sport science has grown considerably in recent years. Even though blood is still the gold standard method for analytical determinations in this field due to its inherent invasiveness, there is a high interest in developing non-invasive analyses, which could be achieved by sampling other biofluids, such as sweat. In particular, microfluidic technology is bringing sweat analysis in real-time to reality ,28.A wide range of biosensors have been developed in recent years ,29,30. SWith the idea of being able to develop robust portable devices for the detection of lactate in sweat, in this work, we investigated the use of alginate beads as a biocompatible biosystem for the determination of lactate concentrations. We present the fabrication of alginate beads, the integration of a lactate enzymatic assay in the beads and the full characterisation of the assay for the determination of the lactate levels in both artificial sweat and real sweat samples using a “fit-to-purpose” colorimetric image analysis method. L-lactate  at a concentration of 800 mM in distilled water and adjusted to a pH of 6.5. Solutions of lactate of 10, 20, 40, 60, 80 and 100 mM were prepared in artificial sweat at room temperature conditions. The solutions were stored at 2–8 °C until use. There was not an effect of varying the concentrations of NaCl and urea in the artificial sweat solution for the range of lactate concentrations of 10–100 mM, see Artificial sweat was made by mixing NaCl , urea  and sodium −1, respectively. Twenty-four milligrams of TMB were dissolved in 2.25 mL of DMSO at 37 °C under continuous agitation for 2 h until its complete dissolution. An initial 2% alginate solution in distilled water was made, at room temperature and continuous agitation conditions, for 4 h until its complete dissolution. An initial solution of 2% alginate was prepared and diluted in distilled water to obtain solutions of 0.25, 0.50, 0.75, 1.00 and 1.50%. A CaCl2  solution was used for the formation of the alginate beads. It was prepared by mixing CaCl2 in distilled water to obtain a 400 mM solution (pH~7.5). All solutions were kept at 2–8 °C.The reaction mix for lactate sensing consists of lactate oxidase , horseradish peroxidase , tetramethyl benzidine  dissolved in dimethyl sulfoxide  and alginate . LOD and HRP solutions were prepared in distilled water to a concentration of 0.40 and 0.05 mg mL2 solution. After 5 min, the formed alginate beads were washed with distilled water for 5 min and dried with filter paper, to remove any excess solution. The pH of the beads was measured from a water solution of 15 hydrogel scaffolds crushed, stored and settled in 1 mL distilled water for 24 h, obtaining a value of ~6.0. This pH should not affect the stability and performance of the enzymes. Then, the beads were placed in a 96-well white plate  and artificial sweat at different lactate concentrations was added for the analysis. Finally, images were taken at different times and analysed with ImageJ to measure the black and white index.For initial fabrication and characterisation, the alginate beads were made by mixing 10 µL of LOD, 10 µL of HRP and 5 µL of TMB solutions with 30 µL of alginate 1% (pH~8). The amount of each component varied during the optimisation experiments, as specified in Bead fabrication and experiments were done at room temperature (25 ± 1 °C). The moisture conditions of the alginate hydrogel diminished the possible small temperature increments of the outside temperature by keeping the enzymes in an active state. Conventionally, evaporation of the water could have an effect, contracting the hydrogel bead, which could exert an external tension on the enzymes, leading to enzyme deactivation. In this regard, to avoid the contraction of the hydrogel, beads were stored in moisture conditions at 10–25 °C and used immediately after fabrication.All the experiments were repeated by triplicate. The diameter of the alginate beads was measured 20 times.Scanning electron microscopy (SEM) images of the freeze-dried alginate beads were recorded by Hitachi S-4800  at an accelerating voltage of 5 kV.3, 3× softbox 50 × 70 cm2, 3× light sources 135 W and 4× background colours, black, white, blue and red, Kissta). The images were later analysed using the image colour analysis software ImageJ. The original colour image was converted to an 8-bit grayscale and the black and white value  of each bead was measured, scaling from 0–255 where black stands for 0 and white for 255.Different images of the alginate beads were taken during the experiments at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 16, 19, 25, 30, 35 and 50 min, using a 20 MP (megapixel) + 2 MP dual camera with an f/1.8 aperture  placed 25 cm over the sample. The same light conditions and camera settings were kept during all experiments using a photography chamber . Then, diffusion started in both directions, that is, lactate entered the bead while LOD, HRP and TMB slowly diffused outside, although this second process was observed to be much smaller due to the stabilisation of the assay components enacted upon the alginate matrix. As this happened, the TMB started becoming oxidised, yielding to the one-electron oxidation blue product inside the bead, giving the capsule a blue appearance (t1), which gradually developed from the edges of the bead towards the centre. On the other hand, outside the bead, the elevated concentration of lactate compared to the enzymatic components induced the complete oxidation of the TMB to its two-electron oxidation state, generating an orange/yellow solution surrounding the bead (t1). Then, diffusion through the alginate membrane continued in both directions, that is, lactate entered the bead while LOD, HRP and TMB diffused outside. As this happened, the TMB continued becoming oxidised, increasing the intensity of the blue colour of the bead. On the other hand, outside the bead the elevated concentration of lactate compared to the enzymatic components that leached out of the bead induced the complete oxidation of the TMB to its two-electron oxidation state. This yielded to an increase in the orange/yellow colour of the liquid surrounding the bead (t2). This condition (higher lactate concentration) remained the same during the length of the experiment, so the intensity of the orange/yellow-coloured liquid increased over time. The orange/yellow colour appeared first in the area closer to the bead, since it is there where the enzymatic assay reacts first with the lactate in the artificial sweat solution. As diffusion inside the bead occurred, the blue intensity increased inside the bead, whereas the yellow intensity in the surrounding liquid also increased due to the second oxidation of the TMB in the solution. This continued until an equilibrium was reached between the solutions outside and inside the bead (t3) and no further increase in the blue colour was appreciated in the bead. A video of the performance of a bead after the addition of 50 µL of solution of lactate 80 mM in artificial sweat is presented in After being added, the lactate solution covered the alginate bead while the enzymatic components of the mix remained inside the bead B, t0. ThAs a first characterisation, the colour of the beads, after adding artificial sweat containing lactate (60 mM), was analysed before and after the washing/drying step. The obtained B/W values are shown in By washing the beads before the addition of the artificial sweat solutions D, the exPBS 1% was also tested as a solution to wash the beads with instead of distilled water, as it is a biological buffer. However, the obtained B/W values of the beads were not as homogenous as the ones obtained when washing with distilled water. Moreover, it was observed that TMB precipitates inside the beads , which aAlginate concentrations of 0.5, 0.75, 1, 1.5 and 2% were tested for the synthesis of the beads. No alginate beads with an alginate concentration lower than 0.5% were tested because the obtained hydrogel would be too weak to form a bead . LikewisThe B/W values of the different alginate beads were obtained when immersing the beads, up to 40 min, in an artificial sweat solution with a lactate concentration of 60 mM, 2O2, promoting just the one-electron oxidation of TMB. Thus, the beads with higher alginate concentrations appeared as a darker blue, with subsequent lower B/W values.The reason behind this phenomenon lies in the concentration of alginate in the bead, which generates thicker beads when the percentage of alginate is increased. In the beads made with higher alginate concentrations, lactate diffused inside slowly, and thus lead to the generation of a lower amount of HAlginate 0.5% and 0.75% beads were fabricated, but their shape was not homogeneous, and they were not robust enough to be used as material in a biosystem. On the other hand, beads made with alginate 2% were robust and the variation in the B/W value, after the assay performance, was small (±3%). However, alginate at this concentration is very viscous, which made its manipulation tedious. Therefore, this percentage of alginate was not used for further developments of the material. Thereby, either alginate 1% or alginate 1.5% were the concentrations that worked the best when preparing alginate beads since they combined an easy manipulation of the alginate, homogenous colour distribution when lactate was added and a good formation as well as durability of the beads. For further experiments, alginate 1.5% was chosen due to its slightly higher robustness. In general, a plateau in the B/W values from minute 13 was observed for all the alginate concentrations, which represents the point where the assay reached the equilibrium.The calibration curve for the lactate assay in the beads made with alginate in the range from 0.5% to 2% at 13 min is shown in Once the concentration of alginate and the mix of enzymes and TMB were optimised for the fabrication of the bead biosystem, different artificial sweat solutions with lactate concentrations of 0, 10, 20, 40, 60, 80 and 100 mM were tested, as the lactate concentration in sweat has been reported to be in the range of 10–70 mM ,35,36. AAt minute thirteen the reaction reached a plateau because of the saturation of the enzymes and the lack of TMB available. Afterwards, the B/W values were stable within the error until minute 35. Since all the lactate concentrations presented distinguishable B/W values at this point, the values were used to build an external calibration curve, In contrast to blood, there is not an established range of lactate concentration in sweat since it depends on fitness level, age, sex, gender and the place where the sweat is collected from ,18,37. TTo verify the potential of using alginate beads as biosystems for lactate determination using image analysis, two samples of artificial sweat were prepared with unknown lactate concentrations. Alginate beads were immersed in the two samples and the B/W values were obtained at 13 min. The values were plotted in the external calibration line, obtaining values of 18 ± 2 and 50 ± 7 mM, respectively . The real values of those two solutions were 20 mM and 45 mM, respectively. These results demonstrated that accurate and reliable measurements of lactate concentrations in artificial sweat could be obtained using an enzymatic alginate bead biosystem.For the validation of the biosystem, real sweat was collected from a healthy female (age 28) after 45 min of indoor cycling. A total volume of 50 µL was collected from the forehead and stored into an Eppendorf tube until use. In order to have enough volume to run three assays, the sample was diluted three times in distilled water. Of the sample, 50 µL was added to the bead and the lactate concentration was measured after 13 min by plotting the measured B/W value into the calibration curve obtained before. A lactate concentration of 48 ± 3 mM (n = 3) was obtained for sweat. The concentration of the sample was also measured using a commercially available device  for the determination of lactate levels, obtaining a concentration of 56 ± 1 mM (n = 3).These results demonstrate that the biosystem developed in this work can, indeed, be used for lactate determination in real sweat samples within the physiological range, after colorimetric analysis of the alginate beads. However, since lactate levels during exercise vary between individuals and over exercise time, no analytical conclusions can be obtained from this result yet. In order to get them, continuous tracking of sweat lactate levels would need to be done by integrating the biomaterial within a wearable device. The implementation of these type of devices has not been solved yet, since it is difficult to obtain reliable sweat samples without compromising sweat analyte concentrations and avoiding contamination ,40,41,42In this work, we have demonstrated and discussed the synthesis and application of alginate beads as novel biocompatible materials for lactate sensing in artificial and real sweat. Lactate concentrations were determined using a colorimetric alginate-based biosystem integrated with LOD, HRP and TMB in 1.5% alginate beads. This method permitted the detection of up to 6.4 mM concentration of lactate and the quantification of up to 21.2 mM of lactate in artificial sweat. Moreover, as a proof of concept, this newly developed biosystem was tested with real sweat samples, demonstrating its possible applicability in real-case scenarios.Compared to standard blood analysis, this new technology provides the possibility of measuring lactate in a non-invasive biofluid, such as sweat. Moreover, since the enzymatic components are immobilised in a hydrogel, the reaction takes place inside the bead, providing higher sensitivity for the colorimetric analysis using image analysis. This, together with the ease of manipulation of alginate beads and lower detection times of up to 15 min, will allow the integration of this biosystem into a microfluidic platform and its application to monitor lactate levels at the point and place of need.The possibility of measuring lactate levels in sweat in its physiological range using alginate bead biosystems and image analysis opens up many options in the development of easy-to-use biosensors for wearable technology and wearable applications. Since alginate is a biocompatible, non-immunogenic and porous hydrogel that can be fabricated at low cost, its use as biosensing material will open new avenues in sensor devices. With lactate being a biomarker of anaerobic metabolism, the work developed here opens a door to a new way of lactate determination by using alginate, with applications in sports science and medicine.


Osteoporotic fractures impose significant costs on society. The objective of this study was to estimate the direct costs of the hip, vertebral, and forearm fractures in the first year after fracture incidence in Iran.We surveyed a sample of 300 patients aged over 50 years with osteoporotic fractures  admitted to four hospitals affiliated to Tehran University of Medical Sciences, Iran, during 2017 and were alive six months after the fracture. Inpatient cost data were obtained from the hospital patient records. Using a questionnaire, the data regarding outpatient costs were collected through a phone interview with patients at least six months after the fracture incidence. Direct medical and non-medical costs were estimated from a societal perspective. All costs were converted to the US dollar using the average exchange rate in 2017 The mean ± standard deviation (SD) age of the patient was 69.83 ± 11.25 years, and 68% were female. One hundred and seventeen (39%) patients had hip fractures, 56 (18.67%) patients had vertebral fractures, and 127 (42.33%) ones had forearm fractures. The mean direct cost  during the year after hip, vertebral and forearm fractures were estimated at USD5,381, USD2,981, and USD1,209, respectively.The direct cost of osteoporotic fracture in Iran is high. Our findings might be useful for the economic evaluation of preventive and treatment interventions for osteoporotic fractures as well as estimating the economic burden of osteoporotic fractures in Iran.The online version contains supplementary material available at 10.1186/s12891-021-04535-8. Osteoporosis is a major public health problem through associated fragility fractures . The worThe clinical significance of osteoporosis lies in the resulting fractures. The most common fractures caused by osteoporosis include hip, spinal, and forearm fractures . The gloOsteoporosis and its related fractures, in addition to their effects on people's quality of life, impose a significant economic burden on families and the health system . FinanciTo the best of our knowledge, there is limited knowledge about the economic burden of osteoporosis and fragility fractures in Iran . TherefoThis was a cross-sectional descriptive study in which we calculated the direct medical and non-medical costs imposed on patients within one year after the common osteoporotic fractures.Direct medical costs included costs of hospitalization, medications, diagnostic tests, physician visits, and diagnostic imaging. Direct non-medical costs included costs of travel for treatment, absenteeism, Informal Care and services, and Patient Time Cost.The study samples included patients visiting teaching hospitals affiliated to Tehran University of Medical Sciences (TUMS) in 2017 due to common fractures caused by osteoporosis, including hip, vertebral, and forearm fractures. Inclusion criteria were age ≥ 50 years, the incident of hip, vertebral or forearm fragility fractures (based on ICD_10 code) in 2017, T-score ≤ -2.5 standard deviation (SD) or fracture due to minor trauma, admission in four teaching hospitals affiliated to TUMS , and surviving at least six months after the fracture incidence. The total number of patients was 476, of whom 71 died, and another 105 were excluded due to unwillingness to participate in the study or incorrect telephone number. Finally, 300 patients participated in the study.Inpatient costs were extracted from hospital records. Outpatient costs were also collected using a questionnaire through telephone interviews with patients. Since outpatient costs occur after hospital discharge, interviews with patients were performed at least 6 months after the occurrence of fracture. In the case of patients unable to answer questions, a family member or caregiver was interviewed who had sufficient information.The study questionnaire consisted of 4 main sections. The first section of the questionnaire was related to patients' demographic information, including age, gender, marital status, place of residence, education status, employment status, and health insurance coverage status. The second section of the questionnaire was related to clinical information and a history of osteoporosis and osteoporotic fractures. In the third section, questions related to resource consumption were asked to calculate direct medical expenses. In this part of the questionnaire, patients were asked what services they had received over the past six months due to osteoporosis and related fractures, as well as the number of times each service was used.For this purpose, a list of services including physician visits, imaging services, medications, diagnostic tests, and rehabilitation services was provided, and patients were asked about the use of each service. The fourth section of the questionnaire was related to direct non-medical costs, and patients were asked about the number of trips, costs of each trip, costs of absenteeism, home care, complementary treatment expenses (such as supplementations), and cost of using equipment such as wheelchairs, cane, etc.The questionnaire was designed based on previous studies and its validity was confirmed through interviews with clinicians and health economists. Also, a pilot study was conducted and the questionnaire was revised based on its result accordingly.Details of methods used for calculating direct medical and non-medical expenses by cost items are presented in supplement Table SDescriptive statistics, including mean, median, and standard deviation, were used to describe the data. To calculate the cost of services for each patient, the number of times each service was used was multiplied by the average price of that service. The price of services was extracted from the official price list for medical services in Iran, approved by the Supreme Insurance Council. Finally, the average annual cost per patient within one year after the fracture had occurred was calculated by the type of cost. Data were analyzed using Microsoft Excel 2013 and Stata software programs . All costs were converted to the US dollar using the average exchange rate in 2017 .Overall, 300 patients  with a mean (SD) age of 69.83 11.25) were included in the study with a total of 127 (42.3%), 117 (39%), and 56 (17.3%) forearm, hip and clinical vertebral fractures, respectively. Other characteristics are shown in Table 1.25 wereThe average direct medical costs during the first year after hip, clinical vertebral, and forearm fracture were estimated to be $3,029.67, $2,316.59, and $924.90, respectively. In all three groups, inpatient costs accounted for the largest share of direct medical costs. The share of inpatient costs out of the total direct medical costs in the hip, vertebral, and forearm fracture patients were 78.88%, 53.70%, and 37.29%, respectively  during the first year after the fracture were estimated to be $ 5,381.30, $ 2,980.78, and $ 1,209.30 for hip, clinical vertebral, and forearm fractures, respectively , excluding them may result in underestimation of the hospitalization costs.Moreover, outpatient costs in Iran are recorded in multiple databases. Taking this into account that some of the out of pockets costs are not recorded anywhere, so the results of the study might be affected by the recall bias since the outpatient costs were estimated through patients’ interviews.Our study showed that common fractures caused by osteoporosis in Iran impose significant costs on patients and society. Due to the increase in life expectancy and the percentage of the elderly population, the incidence and prevalence of osteoporosis and related fractures are increasing that results in higher costs in the future. Implementing cost-effective interventions is necessary to prevent osteoporotic fractures and reduce their associated costs.Additional file 1: Table S1. Methods of measuring direct medical and non-medical costs in this study.


This study proposes a microfluidic device used for X-/Y-sperm separation based on monoclonal antibody-conjugated magnetic beads, which become positively charged in the flow system. Y-sperms were selectively captured via a monoclonal antibody and transferred onto the microfluidic device and were discarded, so that X-sperms can be isolated and commercially exploited for fertilization demands of female cattle in dairy industry. Therefore, the research team used monoclonal antibody-conjugated magnetic beads to increase the force that causes the Y-sperm to be pulled out of the system, leaving only the X-sperm for further use. The experimental design was divided into the following: Model 1, the microfluid system for sorting positive magnetic beads, which yielded 100% separation; Model 2, the sorting of monoclonal antibody-conjugated magnetic beads in the fluid system, yielding 98.84% microcirculation; Model 3, the sorting of monoclonal antibody-conjugated magnetic beads with sperm in the microfluid system, yielding 80.12% microcirculation. Moreover, the fabrication microfluidic system had thin film electrodes created via UV lithography and MWCNTs electrode structure capable of erecting an electrode wall 1500 µm above the floor with a flow channel width of only 100 µm. The system was tested using a constant flow rate of 2 µL/min and X-/Y-sperm were separated using carbon nanotube electrodes at 2.5 V. The structure created with the use of vertical electrodes and monoclonal antibody-conjugated magnetic beads technique produced a higher effective rejection effect and was able to remove a large number of unwanted sperm from the system with 80.12% efficiency. Furthermore, male and female mammalian sperm cells differ in sialic acid content. It was shown that the motility of X and Y chromosome-containing sperm cells differs under a magnetic field, where the female sperm cell is faster than the male.Bovine sperm separation technology has had a significant impact on both the food and livestock industries, leading to an increase in the demand for assisted reproductive technologies (ARTs). Female cattle are required for the dairy industry, while male cattle are preferred in the beef industry  since ma6 sperms/h, as 20 × 106 bull sperms are required for each artificial insemination, resulting in unfeasible sexing lead time during artificial insemination; (2) flow cytometers are expensive ; (3) the conception rate has reduced from 50% to 42%; (4) flow cytometry requires a trained technician [To deploy the difference characteristic of X and Y chromosome for sperm sexing, many sorting techniques have been proposed to achieve high efficiency. The conventional centrifugation based on swim-up (CSW) and direct swim-up (DSW) play roles in non-complicated method but comprise various centrifugation steps and oxidative stress, resulting in sperm DNA damage. Sperm sexing methods based on monoclonal antibody (MAb) specific to Y chromosome-bearing sperm have been used to reduce the sex ratio of male calves. Although the preliminary laboratory tests revealed a higher ratio of X-chromosome bearing sperms than that of Y-chromosome bearing sperms , MAb haschnician . In the chnician ,12, dielchnician , electrochnician ,15,16, mchnician ,18,19, schnician ,23,24,25chnician ,27, elecchnician , inertiachnician , and conchnician . AnotherTo increase the performance of sperm sorting based on electrophoresis technique, we present LOC integrated with MWCNT electrodes, which provides the possibility for increasing the performance both effectiveness and productivity. The conventional method of magnetic beads trapped the Y-sperms in a test tube.Based on the property of Mab, which traps the Y-sperms and conjugates with magnetic beads directly, electrophoresis microfluidic chip can be utilized to control the moving direction of magnetic beads easily, resulting in Y-sperms sorting from X-sperms. Based on the concept of MAb conjugated magnetic beads working under MWCNTs electrodes in microfluidic chip, all sperms will interact under the same electrostatic filed condition, especially for magnetic beads, which offer positive charge on the surface that will be attracted to the negative electrode. The Y-sperms trapped to magnetic beads were sorted out at the exist microchannel, which allowed the X-sperms to flow. Moreover, this strategy can apply a permanent magnet to keep all magnetic beads at the exist microchannel to collect the X-sperms.In this study, antibody-conjugated magnetic beads for sperm sexing using a MWCNTs microfluidic device is proposed to increase the efficiency of electrophoresis sperm sorting technique. Magnetic beads with positive charge attached to Y-sperms with MAb and moved them to the MWCNT negative electrode in microfluidic chip. Most of magnetic beads were forced to move to the exist microchannel leaving all X-sperms to interact with the electric field, thereby purifying them. In addition, attracting magnetic beads with a permanent magnet at the outlet of the microfluidic chip can improve the quality of the desired sex sperm and show specificity and accuracy in terms of gender separation.The conventional magnetic beads applied for sperm sorting  is shownCarbon plays an important role in the development of electrochemical biosensors ,32,33 an3 with a binding capacity of ≥ 26 µg of rabbit IgG/mg of beads. The magnetic beads have an amine functional group consisting of an N atom bonded either to C or H atoms via σ bonds. Both the C-N and N-H bonds are polar due to the electronegativity of the N atom. Therefore, these magnetic beads have positive charges that associate with the Y sperm, the unwanted target sperm, and are isolated using a fabricated microfluidic structure to remove them, leaving only the X sperm. To ensure sperm X and Y purity, those that could still be aspirated by the microfluidic structure were re-purified via magnetic traction. This ensures that the final X sperm have the highest separation rate and are not contaminated with any material.Magnetic beads were used to add charge to the sperm with monoclonal antibody 1F9, since monoclonal antibody 1F9 is specific to Y sperm. According to the hypothesis of different surface charges of X and Y sperms, the X sperms were had a greater net negative charge than Y sperms  The applThe MAb reaction test conducted using a flow cytometer for screening of sperm sex was divided into two groups: the control sample test and its negative result  and a monoclonal antibody 1F9, which is an IgG antibody that binds to the H-Y antigen located on the surface of Y sperm-specific cells. The control samples were A01 and A02; A01 was the conjugate control (CC), which consisted of 50 μL of FACS buffer and 50 μL of bull sperm; A02 was isotype control (IC), which consisted of 1 μL of ST28A antibody, 50 μL of FACS buffer, and 50 μL of bull sperm. However, there is no specificity for the sperm that it should not bind to the sperm. The control samples A01 and A02 are collectively referred to as negative controls (NC).Comparison with the NC sample revealed that the MAb 1F9 affected the bindable sperm, as mentioned above. NCs are unable to bind to sperm. However, the positive results obtained with the 1F9 MAb revealed that the 1F9 MAb could bind to sperm. A03 consisted of 50 μL of 100 μg/mL MAb, with a final 1F9 MAb concentration of 50 μg/mL. A04 consisted of 50 μL of 50 μg/mL MAb and 50 μL of bull sperm, with a final 1F9 MAb concentration of 25 μg/mL. A05 consisted of 50 µL of 25 µg/mL MAb and 50 µL cow sperm, with a final 1F9 MAb concentration of 12.5 µg/mL. Finally, A06 consisted of 50 µL of 12.5 µg/mL MAb and 50 µL of cow sperm, with a final 1F9 MAb concentration of 6.25 µg/mL. The parameter of test sample A01-A06 was describing at the Magnetic particles were prepared by balancing protein and magnetic particles at 25 °C, and then 300 μL of magnetic particles were inserted into a 1.5 mL microcentrifuge tube at shown the procedure in 6 spermatozoa preserved in liquid nitrogen was thawed in a water bath at 37 °C for 40 s. Thereafter, the sample was placed into a 1.5 mL microcentrifuge tube and stored in a chamber at a temperature of 37 °C. Live sperm with mortality greater than 70% was used. One microliter of warm PBS extender at 37 °C was added to remove the egg yolk extender from the spermatozoa. Subsequently, a tube of sperm sample was centrifuged at 16,128 g for 10 s thrice, and the supernatant was discarded to collect the sperm pellet. Turk’s solution was mixed with sperm at a ratio of 1:10. Then, the sperm was blocked with AB serum (FC Receptor) for 30 min. Finally, a total of six sperm tubes were prepared: Tube 1, monoclonal antibody 100 μg/mL, 50 μL volume, 50 μL sperm, and A08. Tube 2, 50 μg/mL monoclonal antibody, 50 μL volume, 50 μL sperm, and A08. Tube 3, 25 μg/mL monoclonal antibody, 50 μL and 50 μL sperm and A08. Tube 4, 12.5 μg/mL monoclonal antibody, 50 μL volume, 50 μL sperm, and A08. Tube 5, 1 μL ST28A antibody, 50 μL FACS buffer, 50 μL sperm, and A08. Tube 6, 50 μL FACS Buffer, and 50 μL sperm and A08. The best-conjugated combination was in Tube 3.The Holstein Friesian bull semen samples used in this study were purchased from the Dairy Farming Promotion Organization of Thailand. A single straw of bull semen sample containing 30 × 10The design of the microfluidic chip, which mainly consists of a Y channel cell microfluidic channel with a pair of electrodes positioned at the separation regions, is shown in 3) and HF3% for Au and Ti layer, respectively. Photoresist, last, was removed with acetone to achieve the final electrodes  functional groups on the blocked magnetic bead surface. Using electrophoresis, the magnetic beads were tested by separating the beads on a microfluidic device using the principle of the charge on the surface of magnetic beads. Electrophoresis is a laboratory technique used extensively to separate DNA, RNA, or protein molecules based on their size and electrical charge. Therefore, the optimized condition for the separation of charged beads, as understood from Phiphattanaphiphop’s research, included a microfluidic device with a 150 μm microchannel and 100 μm electrode distance and showed the highest performance of 87.07% validation (95% confidence level) for the separation of negatively charged TiOPS beads . An optiMoreover, magnetic particle beads were tested on the MWCNT electrode microfluidic chip. It was processed into a pelletized form for use in the microelectrode area. The magnetic particle beads were controlled using a BS-8000 syringe pump  at a flow rate of 2 µL/min. The MWCNT-microfluidic system device could separate magnetic particle beads with 100% success, as shown in The MAb conjugated with magnetic particles for better sperm separation was pumped into the microfluidic chip. An experiment was conducted for separating various particles using magnetic particles on a MAb based on the properties of MAbs and magnetic particles by controlling the sample flow rate at 2 µL/min. It The microfluidic device could separate the magnetic particles on the MAb. The percent of sample successfully sorted results were achieved at 95.42%, as shown in the Sperm and sperm with MAb-conjugated magnetic particle beads were added to achieve better separation on a microfluidic chip compared with that on a MWCNT-microfluidic chip. The sperm with MAbs conjugated with magnetic particles in a microchannel in a microfluidic system device and microelectrode was tested. The particle flow was observed in the microscopic flow channel. The particle inflow rate was controlled at 2 µL/min, and the electric fields were discharged at 2.5 V for the microfluidic chip. The results analyzed using RT-PCR were achieved at 61.11% and 80.12% for sperm conjugated MAbs and magnetic particle beads, respectively, as shown in the microfluidic chip and MWCNT-microfluidic chip, respectively in The micro-fluid system and micro-electrodes were created for separating magnetic particles beads, monoclonal antibodies conjugated with magnetic particle beads and sperm and sperm with monoclonal antibodies conjugated magnetic particle beads with the device. The particle flow was observed in the microscopic flow channel. In the present study, three sorting patterns were examined: Model 1, the microfluid system for sorting positive magnetic beads; Model 2, the sorting of monoclonal antibody-conjugated magnetic beads in the fluid system, and Model 3 sorting monoclonal antibody-conjugated magnetic beads with sperms in the microfluid system. Two types of separation structures were designed; the first was designed by generating a thin-film electrode with a thickness of 50 nm via the UV lithography process. The second was designed by generating a wall electrode with a larger thickness that generated an electric field using MWCNT to obtain a vertical wall structure with a thickness of 1500 µm. Owing to the thickness of the electrode in the second design and as UV-lithography does not yield sharp wall angles in the structures, X-ray lithography was used instead of UV-lithography. As shown in The results of the magnetic particle separation experiment in which the inflow rate of magnetic particles was maintained at 2 μL/min, with a 2.5 V electric field, revealed that the magnetic particles were released into the microstructure flow channel in the microfluidic chip. Magnetic particles beads flowed through the main flow channel and into the negative-ion flow channel. The magnetic particles released into the microstructure flow channel were positively charged at the north poles. Therefore, the magnetic particles flowed out of the negative-ion flow channel rather than the positive charge flow channel. According to the theory of electricity and magnetism, particles with same polarity or charge repel each other. This shows that the generated microfluid system device can separate magnetic particles with a success rate of 100% on both the microfluidic chip and MWCNT-microfluidic chip, as shown by flow cytometry.The MAb 1F9 was conjugated with magnetic particle beads. MAb 1F9 only reacts with Y sperms; in other words, MAb 1F9 binds to Y sperms. Positively charged magnetic particle beads conjugated with MAbs 1F9 are attracted by the generated microfluidic device structure. By generating an electric field at 2.5 V, the device could selectively screen antibody-coated magnetic beads with a success rate of 95.42% in thin-film electrodes microfluidic chip and 98.84% in the MWCNT electrodes microfluidic chip. The analyses were conducted using a flow cytometer. Therefore, the magnetic particles flowed out of the negative electrode flow channel rather than the positive electrode flow channel. The MAbs with magnetic particles had high effect on electric field, which could adjust the amplitude voltage from 1 to 2.5 V. The magnitude of the electric field at 2.5 V was the maximum value of the electric field, which can be used without forming air bubbles or adversely affecting the microfluidic systems. This shows that the generated microfluidic system device can isolate magnetic particle beads on a MAb.Sperm sexing experiments conducted on magnetic particle beads on a MAb via control of the inflow rate of the sample at 2 μL/min and release of a 2.5-V electric field revealed that the sperms working with magnetic particles on the MAb were released into the microstructure flow channel. Sperms with monoclonal antibodies conjugated magnetic particle beads flow through the main flow channel separately to both exits—the positive charge flow channel and the negative charge flow channel. To obtain clear results, the accuracy was checked using real-time PCR.The analysis of the sperm screened with the microfluidic system using real-time PCR was used to determine the DNA content of the Y sperm in the sample. From the conventional method of thin film electrodes and MWCNTs electrodes microfluidic chip  which doAlthough 5% increase in Y-sperm separation efficiency was not enough for bovine sperm sexing process when compared with the conventional method, it can be improved by applying a permanent magnet at the exist of microchannel and adjust microchannel parameters. Only MAb conjugated magnetic beads showed an 80% success rate under electrophoresis, suggesting that the X-sperm success rate is also increase.The new method for X-sperm sorting by trapping of Y-sperm with magnetic beads was proposed to achieve high efficiency when compared with the basic electrophoresis sorting method without magnetic beads. The process was based on electrophoresis, which utilized electric field to separate X-sperm in the mainstream and Y-sperm with MAb conjugated magnetic beads. From the experimental results, sorting method with magnetic beads provided a better efficiency than that without magnetic beads since positive charge magnetic beads can enhance Y-sperm sorting efficiency at the exist microchannel to 80%. Based on the same moving distance in the mainstream, the flow of X-sperms to a positive electrode was faster than that of Y-sperms since the net negative charge of X-sperm was greater than that of Y-sperm, resulting in the distribution of X-sperm at the upper exist microchannel by adjusting the applied electric field condition from 1 to 2.5 V. For the MWCNT electrodes microfluidic chip, moreover, the length of the mainstream for electrophoresis separation and height of the microchannel were 13,000 µm and 1500 µm, respectively, allowing X-sperms to be continuously attracted by a positive electrode along the flow stream and separating them from Y-sperms and Y-sperm conjugated magnetic beads at the exist microchannel. To achieve higher efficiency, microchannel parameter adjustment may be necessary, especially for flow resistance, microchannel dimension, and number of exist microchannels. Since there were three types of charge particles in the mainstream, Y-sperm conjugated magnetic beads, Y-sperm non-conjugated magnetic beads, and X-sperms, the exist microchannel could be designed for three corresponding microchannels by varying the width. This design would allow the charged particles to be directed to a specific fraction by adjusting the applied electric field  as well In this study, magnetic particle beads were designed for conjugation with MAb-specific Y sperm to separate it from X sperm, with the objective of obtaining the X sperm for commercial use in dairy cow production. Separation of magnetic particles beads, monoclonal antibodies conjugated with magnetic particle beads and sperm, and sperm with monoclonal antibodies conjugated magnetic particle beads were performed using a microfluidic system, designed using MWCNTs for separation by sexing X and Y sperms. Separation was performed based on the assumption that the X and Y sperms had different electrical charges on the surface. The microfluidic devices used here were designed based on the optimal values from previous research in which a microfluidic device with a 150-μm microchannel and 100-μm electrode distance were used, and the structure was obtained from MWCNT-microfluidic chip . Based o


Chemical compounds can be represented as attributed graphs. An attributed graph is a mathematical model of an object composed of two types of representations: nodes and edges. Nodes are individual components, and edges are relations between these components. In this case, pharmacophore-type node descriptions are represented by nodes and chemical bounds by edges. If we want to obtain the bioactivity dissimilarity between two chemical compounds, a distance between attributed graphs can be used. The Graph Edit Distance allows computing this distance, and it is defined as the cost of transforming one graph into another. Nevertheless, to define this dissimilarity, the transformation cost must be properly tuned. The aim of this paper is to analyse the structural-based screening methods to verify the quality of the Harper transformation costs proposal and to present an algorithm to learn these transformation costs such that the bioactivity dissimilarity is properly defined in a ligand-based virtual screening application. The goodness of the dissimilarity is represented by the classification accuracy. Six publicly available datasets—CAPST, DUD-E, GLL&GDD, NRLiSt-BDB, MUV and ULS-UDS—have been used to validate our methodology and show that with our learned costs, we obtain the highest ratios in identifying the bioactivity similarity in a structurally diverse group of molecules. The high increase in chemical compounds data has created the need to develop computational tools to reduce the drug synthesis and drug test cycle runtimes. When activity data are analysed, these tools are required to generate new models for virtual screening techniques ,2,3. In Some LBVS approaches are shape-based similarity , pharmacTo compute molecular similarity, it is necessary to define a distance and define a descriptor representing the molecule. Hundreds of molecular descriptors have been reported in the literature . For insTo perform reduced graph comparisons, three different similarity measures have been used: In ,29,32, tIn an initial paper , the ediThe main problem of the algorithm in  was the The outline of this paper is as follows. First, materials and methods are explained in detail, including the datasets, the GED and the learning algorithm. Second, the results of the practical experiments are described and discussed. Third and finally, a general discussion about the method and the results is presented.In this study, we have used six available public datasets: ULS-UDS , GLL&GDDReduced graphs are compact representations of chemical compounds, in which the main information is condensed in feature nodes to give abstractions of the chemical structures. Different versions of reduced graphs have been presented ,30,32,33We explain our proposed method in the next three subsections. The first one explains the classification of compounds based on structural information; in the second one, we explain the learning algorithm; and in the third one, we detail the code of the algorithm.Once the molecules are represented as ErGs, we can compare them by means of the Graph Edit Distance (GED) ,48. The Edit costs have been introduced to quantitatively evaluate each edit operation. The aim of the edit costs is to designate a coherent transformation penalty in proportion to the extent to which it modifies the transformation sequence. For instance, when ErGs are compared, it makes sense that the cost of substituting a “hydrogen-bond donor" feature with a joint “hydrogen-bond donor-acceptor" feature be less heavily penalized than the cost of substituting a “hydrogen-bond donor" feature with an “aromatic ring" system. Similarly, inserting a single bond should have a lower penalization cost than inserting a double bond, and so on. In a previous work , the ediThe final edit cost for a given transformation sequence is obtained by adding up all of the individual edition costs. Since several transformation sequences can be applied to transform a graph into another one, the GED resulting for any pair of graphs is defined as the minimum cost under all those possible transformation sequences. Usually, the final distance is normalized according to the number of nodes in both graphs being compared. This is performed in order to make the measure independent of the size of the graphs.L is the sum of the number of nodes of both graphs, and n is the number of different edit operations on nodes and edges.More formally, we define the GED as follows,Several GED computational methods have been proposed during the last three decades, they can be classified into two groups: those returning the exact value of the GED in the exponential computational cost with respect to the number of nodes , and thoInitially, the edit costs were manually set in a trial and error process considering the application at hand ,34.  and and6) anIn the next subsection, we present our algorithm.Algorithm 1 Costs learning.Input Output (Learnt edit costs)Initialise:WhileClassify all molecules with nearest neighbour and   Equation ) using CCompute : (Equations (  quations  and 3)))Compute Deduce  Equation ).Compute  (Equation (  Equation ).Compute  Equation ).Update costs:    End While End AlgorithmAlgorithm 1 consists of an iterative process in which, in each iteration, the edit costs are updated to correct the classification of one selected molecule. The updated costs are used in the next iteration to classify all the molecules again, select a molecule and modify the costs again.https://deim.urv.cat/~francesc.serratosa/SW/, accessed on 12 November 2021.This algorithm has been coded in Matlab, and it is available in We realise that in all the datasets, except for MUV and ULS-UDS, our costs with Harper initialisation obtained the highest classification ratios. In these two datasets, the best accuracy is obtained by Harper costs. Note that our method initialised by all-ones costs returns lower accuracies than our method initialised by Harper costs, except for the ULS-UDS dataset. This behaviour makes us think that the initialisation point is very important in this type of algorithm. Another highlight is that we have achieved better accuracies than the four experiments presented by García et al.  in all tIn Note that in , authorsWe present an iterative algorithm such that, in each iteration, the current costs are modified to properly classify an improperly classified molecule. While updating the costs, other improperly classified molecules could also be properly classified and vice versa. This is the reason why we cannot guarantee the algorithm’s convergence. To reduce the no-convergence impact and the possible solution oscillation, the algorithm selects the molecule that requires the minimum modification of the costs with the aim of slightly moving to the best solution.The algorithm requires some initial costs. We have initialised the algorithm by some aleatory costs and by the costs proposed by Harper . In all In some ligand-based virtual screening (LBVS) methods, molecules are represented by extended reduced graphs. In this case, the Graph Edit Distance can be used to compute the dissimilarity between molecules.In this article, we have presented a new method that automatically learns the edit costs in the Graph Edit Distance. In each iteration, our method introduces slight modifications in the current costs to correct the classification of a selected molecule that had been incorrectly classified in the previous step.The obtained costs have been tested in six publicly available datasets and have been compared to previous works published in ,35. We aIn the experimental section, we realised that small modifications in the costs could produce considerable improvement in the classification ratio.In future work, we will analyse which types of molecules cause the algorithm to converge and which are the best initial values to obtain higher classification accuracy.


A total of 60 positive nucleic acid samples for different pathogens were detected, a concordance of 100% was observed between microarray assay and real-time PCR analysis. Consequently, the described oligonucleotide microarray may be specific and sensitive assay for diagnosis and surveillance of infections caused by Ebola virus and other species of hemorrhagic fever pathogens.Ebola virus infection causes severe hemorrhagic fever, and its mortality rates varied from 25 to 90% in the previous outbreaks. The highly infectious and lethal nature of this virus highlights the need for reliable and sensitive diagnostic methods to distinguish it from other diseases present with similar clinical symptoms. Based on multiplex polymerase chain reaction (PCR) and oligonucleotide microarray technology, a cost-effective, multipathogen and high-throughput method was developed for simultaneous detection of Ebola virus and other pathogens associated with hemorrhagic fever, including Marburg virus, Lassa fever virus, Junin virus, Machupo virus, Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, malaria parasite, hantavirus, severe fever with thrombocytopenia syndrome virus, dengue virus, yellow fever virus, Chikungunya virus, influenza A virus, and influenza B virus. This assay had an excellent specificity for target pathogens, without overlap signal between the probes. The limit of detection was approximately 10 Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a severe, often fatal illness in humans. The first outbreaks of Ebola virus were documented in Sudan and the Democratic Republic of Congo in 1976 . Since iThere is a persistent need for cost-effective and reliable approaches for distinguishing Ebola virus from other pathogens associated with hemorrhagic fever. Currently, the laboratory methods for detecting Ebola virus include polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA), immunohistochemistry, virus isolation, etc. . HoweverOligonucleotide microarray, a highthroughput technology that is accurate, speedy, and low-cost has been used for disease diagnosis, pathogenic microorganism detection, gene expression analysis, single-nucleotide polymorphism (SNP) detection, and genome sequencing . In thisSerum or plasma specimens, blood samples, and clinical throat swab samples were collected from the Zhejiang Provincial Center for Disease Control and Prevention (CDC) and Chinese PLA Academy of Military Medical Sciences (AMMS). Total RNA or DNA were extracted by QIAamp MinElute Virus Spin Kit or QIAamp DNA Blood Mini Kit .1 The sequences were then aligned using AlignX (a component of the Vector NTI Advance 10.3.0). We designed primers to amplify the specific sequences of each pathogen mentioned above. Moreover, microarray probes ranging from 19 to 45 nucleotides were designed to detect targeted sequences of the 16 pathogens. Eventually, 29 primers and 16 were selected that accurately identified targeted pathogens. All the primers and probes were verified by BLAST2, and the sequences are shown in Gene sequences for ZEBOV, SEBOV, MARV, LFV, JUNV, MACV, RVFV, CCHFV, MP, HV, SFTSV, DENV, YFV, CHIKV, FluA, and FluB were downloaded from the nucleotide database of NCBI.All microarray probes were synthesized by Sangon Biotech Co., Ltd. , and a repeat sequence of 12T with an amino-labeled 3′end was connected to the 3′-end of all the probes for fixation to the aldehyde-chip surface. The microarray was composed of 10 multiwell grid holes, and each multiwell grid holes was composed of 48 points. Probes, at a 50 mM final concentration, were spotted onto the aldehyde chip after mixing with uniform proportional printing buffer . The microarray was placed in a dryer for 24 h at room temperature, and unbound probes were removed by washing once with 0.2% SDS and once with distilled water for 30 s each at room temperature prior to use. The microarray layout is shown in The 16 pathogens associated with hemorrhagic fever were divided into three groups for higher amplification efficiency. The specific fragment of each pathogen in each group was respectively amplified by a multiplex RT-PCR system. Each multiplex RT-PCR was performed in a 25-μl reaction volume containing 12.5 μl of 2 × One Step Buffer, 5 μl of template nucleic acid, and 1 μl of PrimeScript One Step Enzyme Mix . The primers for the three different RT-PCR systems are listed in After the targeted fragments were amplified, 2 μl of each amplification product of the three reactions was mixed with 6 μl of hybridization buffer . A total of 10 μl of hybridization mixture was added to the hybridization region on the microarray, then the chip was placed in a hybrid box, and incubated for 1 h at 45°C. Subsequently, the chip was washed once for 20 s with 1 × SSC and 0.2% SDS, followed by 0.2 × SSC, and 0.1 × SSC at room temperature.In this assay, we introduced a chemiluminescence approach for signal detector. After hybridization and washing were complete, the chip was incubated with 15 μl of 25 nM streptavidin-horseradish peroxidase  for 30 min at 37°C. Then, the chip was washed with phosphate buffered saline with 0.05% Tween 20 (PBST) for 20 s at room temperature. Subsequently, 20 μl of Chemiluminescent HRP Substrate  prepared before use was added, and the chip was scanned by Chemiluminescent Imager . The probe signal densities were quantified by Arrayvision 7.0. The cutoff value for each probe was calculated through the mean of the spot intensity in order to determine the signals objectively.in vitro and also used as templates to assess the specificity of the microarray. The sensitivity of the microarray analysis was evaluated by serial 10-fold dilutions of in vitro-transcribed RNAs (ranging from 105 to 101 copies/μl). Ebola virus (Zaire) Nucleic Acid Detection Kit   was also used as references for sensitivity evaluation.Clinical specimens that were confirmed and genotyped previously by Department of Microbiology, Zhejiang CDC, were used as positive controls for MP, HV, SFTSV, DENV, CHIKV, FluA, and FluB. The targeted genes of the remaining pathogens were synthesized by Sangon Biotech Co., Ltd.  and used for plasmid construction. Then, the RNAs were transcribed Sixty positive samples with nucleic acid of different pathogens (including 45 Zaire ebolavirus RNAs which were extracted from inactivated Zaire ebolavirus culture samples), were provided by the Chinese People’s Liberation Army (PLA), Academy of Military Medical Sciences (AMMS), and Zhejiang CDC, were detected by microarray analysis and commercial PCR kits. These dangerous infectious agents were handled in BSL-3 facilities of Zhejiang CDC for safety and surety. Agreement between the microarray assay and Real-Time RT-PCR assay was assessed.The microarray assay was able to well distinguish nucleic acid of ZEBOV, SEBOV, MARV, LFV, JUNV, MACV, RVFV, CCHFV, MP, HV, SFTSV, DENV, YFV, CHIKV, FluA, and FluB. Also, no overlapping signal between the probes was observed. Results are shown in in vitro transcribed RNAs (ranging from 105 to 101 copies/μl). Based on the positive signals generated, the sensitivity of the assay was 103 gene copies for ZEBOV, SEBOV, MARV, LFV, JUNV, RVFV, CCHFV, HV, SFTSV, DENV, YFV, CHIKV, FluA, and FluB. For MACV and MP, the detection limit was 102 gene copies . A total of 60 positive samples with nucleic acid of different pathogens were tested by our microarray and commercial kits . The ZEBThe Ebola virus is one of the greatest human infectious disease threats, with an average EVD case fatality rate approximating 50%, varing from 25 to 90% in past outbreaks  accordin3 copies/μl  the GP protein of Ebola virus is required for entry into cells, (2) the membrane-bound GP is an important virulence factor of Ebola virus and plays a central role in the virus-mediated cytotoxicity of endothelial cells, and (3) sequence analysis of the GP genes of Ebola virus revealed that regions within this gene would be relatively conservative in evolution . As moreA total of 60 samples of Ebola virus and other pathogens were tested by our microarray and compared with commercial real-time RT-PCR kits. A concordance of 100% was observed between the two methods . HoweverIn conclusion, a cost-effective, multipathogen, specific, and sensitive oligonucleotide microarray assay was developed to detect Ebola virus and pathogens associated with hemorrhagic fever. This microarray was fast and high throughput, with the entire procedure, from extraction to microarray detection, could be completed within 5.5 h. The detection cost per sample was less than five US dollars. This oligonucleotide microarray will prove to be useful for treatment, prevention, surveillance, and epidemiological studies of Ebola virus.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.This study was approved by the Academic Committee of Zhejiang Provincial Center for Disease Control and Prevention and all experiments were carried out in accordance with the approved guidelines. The human materials used were serum or plasma specimens, blood samples and throat swab samples, and all patients provided written informed consent.HY and YZ designed the study. HY and WY performed the experiments. ZY analyzed the data and wrote the discussion part of the manuscript. XL and HM wrote the “Results” section of the manuscript. All authors reviewed the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The high costs of chronic conditions call for new treatment approaches that reduce costs while ensuring desirable health outcomes. There has been a growing transformation of care delivery models from conventional referral systems to integrated care models. This study seeks to evaluate the cost-saving impact of integrated care delivery model under pay-for-performance (P4P) scheme with continuity of care at institution level (ICOC).We analyzed the Taiwan National Health Insurance claim data of 21,725 diabetic patients who visited clinics and/or hospitals at least four times a year for 8 years. Using average local provider P4P participation rate (for each accreditation level) as an instrumental variable in two-stage least squares (2SLS) regressions, we have estimated consistent estimates of the ICOC elasticities for all-cause inpatient and outpatient costs.Our results show that ICOC significantly reduced inpatient costs but increased outpatient costs with the elasticity for treatment costs of -11.6 and 1.03, respectively. The decrease in inpatient costs offset the increase in outpatient costs and the resulting total cost saving showed significant association with ICOC. The saving effect of ICOC is especially robust among patients who used clinics as their principal source of care.Institutional continuity of care has a substantial impact on the treatment costs of diabetes patients. In the context where inpatient care costs are significantly higher than that of the outpatient care, ICOC would lead to a meaningful cost-saving effect. For new diabetes patients, care by clinics demonstrated the strongest saving effect. In 2019, approximately 463 million adults (20–79 years) were living with diabetes. By 2045, the International Diabetes Federation (IDF) estimates this number will rise to 700 million adults; a 51 % increase :2\d:2\d25]:2i,t is the total number of outpatient visits made by patient i during year t. The number of visits to institution j is denoted as ni, j, t. The ICOC score ranges between 0 and 1, with 1 indicating the highest degree of continuity. The ICOC score for the same number of visits varies according to the number of institutions that provided care to the patient. More institutions involved in providing the patient care, the lower the ICOC score would be for the same total number of visits. Appendix where NTo consistently estimate the cost-saving effect of ICOC, we need to address the potential endogeneity of ICOC. While COC is mainly affected by personal traits and interaction with physician, ICOC is further affected by patient health and provider characteristics . For exaAnother reason that ICOC may be endogenous is a result of Taiwan’s NHI payment design. Without formal primary care physician (family doctor) arrangement, patients can self-select themselves into different types of principal providers. Typically, patients with more severe conditions prefer medical centers whereas those with minor conditions would choose clinics as their principal providers . NHI reii, t. All variables in Eq.  is chosen to predict individual ICOC scores. The criterion for choosing an IV is that the variable is closely related to ICOC but exogenous to the dependent variable, i.e., the treatment costs, so the IV will not correlate with the error terms Ɛs in Eq.  and the In the first stage, we chose the “average local provider P4P participation rate (for each accreditation-level)” as the IV. Unlike the family member COC which Pu et al. chose as the IV for patient COC, ICOC in this study is much more closely related to provider characteristics . The aveWe began analyses with panel OLS to examine how changes in the values of variables might affect the treatment costs. Hausman tests were used to determine whether patient-specific costs were random or fixed. Then we focused on the 2SLS estimates for the cost-saving effect of ICOC, and compared with OLS results. We allowed the ICOC variables in the regressions to lag by 1 to 3 years to mimic the common practice of using COC at baseline to predict the cost effect in the following years. Finally, we used subsamples of patients who patron clinics as principal care provider to re-estimate the ICOC elasticities for treatment costs to investigate how ICOC elasticities change with provider characteristics.The patient characteristics, as shown in Table The conventional thinking is that patients may need to visit larger hospitals as their conditions progress, and they need more specialist care. The patients in this study, however, by 2009, tended to use clinics more as their principal providers, perhaps because during this time Taiwan was experiencing an increasing number of small-scale for-profit hospitals closure while more clinics were entering the market. Also, during this period, only 24 % of clinics participated in P4P program but almost all medical centers and regional hospitals had some physician-led teams that have joined P4P.As for the treatment costs, patients using clinics as their principal providers incurred the least costs while patients with the regional hospitals or medical centers at higher accreditation level incurred higher treatment costs. For all providers, the average outpatient costs, not surprisingly, were approximately half of the inpatient costs. Annual numbers of admissions were as low as 0.18 for patients cared at clinics in 2009.Table The Andersen-Rubin Wald F statistics rejected the hypothesis that average local provider P4P participation rate was a weak instrument, and the Wald test for endogeneity supported that ICOC was endogenous for both outpatient and inpatient costs. Though ICOC illustrated opposite effects in outpatient and inpatient costs, ICOC elasticity for total costs was − 1.07 and reached statistical significance.Table This study established ICOC as a potentially new index to investigate the cost-saving effect using an 8-year database of newly diagnosed diabetes patients. As many medical groups are adopting an integrated team care approach for chronic disease management, this ICOC index serves as a valid and reliable indicator to provide important policy reference in the evidence-based policy making process. Furthermore, we think it is essential to use a 2SLS method to discern the ICOC’s elasticities for outpatient and inpatient costs in order to avoid the problem of endogeneity. This study’s findings are against the common practice of treating COC as exogenous in analyzing inpatient use/costs. The advantage of using 2SLS estimation model is to reduce potential bias caused by endogeneity of the key variable, ICOC. For example, a patient who is health-conscious and complying to the doctor’s orders would likely show higher ICOC whilst maintaining good health. In this case, the cost-saving effect of ICOC and unobserved individual effect  may not be disentangled. While analyzing the ICOC effect on the outpatient costs with a single OLS equation, the estimated elasticity is -0.07, meaning a 1 % increase in ICOC score would reduce outpatient costs by 0.07 %, a combined effect of ICOC and personal health-consciousness. Hence, we exploited the local prevalence of P4P program as an IV for ICOC, by design, the IV is related to ICOC but not unobserved individual effect, therefore producing a cost-saving effect solely attributed to ICOC. The ICOC elasticity of 1.03 from the 2SlS model signifies a 1 % increase in ICOC score will actually increase outpatient costs by 1.03 %, which is an unbiased estimate of cost-saving effect.Through IV, we have estimated the average effect of the ICOC on health costs, and the Andersen-Rubin Wald F statistics rejected the hypothesis that average local provider P4P participation rate was a weak instrument. However, in nonexperimental settings, when treatment effects  are (likely to be) heterogeneous, it may not be possible to draw inferences about the effect of treatment in the population represented by a particular sample of people . That isOur findings also have shown that an increase in the ICOC score is associated with an increase in outpatient costs and a decrease in inpatient expenses. The net effect is that an increase in the ICOC score is associated with a significant saving effect on the total treatment cost.The estimated ICOC elasticity of -11.6 for inpatient costs have shown great sensitivity of inpatient costs towards changes in ICOC value, which might be attributable to the nature of the ICOC: (1) ICOC has a small range of value between 0 and 1, therefore a change in the number of outpatient visits may result in only a small percentage change in ICOC. (2) Many patients incurred zero inpatient cost , hence a decrease in inpatient costs is likely to result in a substantial change in costs in percentage. As the distribution of inpatient costs has a big spike of zeros and is skewed to the right, the ICOC elasticity estimated from the 2SLS might be biased. In light of recent development in analyzing health care expenditures with generalized linear models (GLM) and two-stage residual inclusion (2SRI), we did a robustness check using 2SRI with GLM to estimate ICOC elasticity for inpatient costs , 36. TheThe estimated ICOC elasticity for total costs is -1.07, which means at the sample average ICOC (around 0.8), a 1 % increase in ICOC score would decrease total costs by 1.07 %. To the best of our knowledge, no study has ever estimated ICOC elasticity. However, quite a few studies have used elasticity to assess the impact of cost-sharing on total spending, and the estimated arc price elasticities range between 0.14–0.43; 0.10–2.Two research constraints bear noting. First, our findings are applicable only to new diabetes patients who could maintain at least 4 visits per year. Second, in some township where there is only one hospital, the average P4P participation rate equals to that provider’s P4P participation decision (zero or 1) and may be subject to endogeneity problem. Nonetheless, as the majority of townships (ranging from 91 to 93 % during the observation period) have more than one provider, the endogeneity issue is likely to be ameliorated.This study expands the boundary of continuity of care (COC) to explicitly incorporate the COC effect at the institutional level and then evaluates the relative cost-saving effects of ICOC among outpatient, inpatient, and total treatment costs. Institutional characteristics are likely to have impacts on treatment costs for diabetes patients. Institutional continuity of care (ICOC) is associated with higher outpatient costs but lower inpatient costs. Clearly, ICOC’s impact on total treatment costs depends on the relative magnitude of effects on inpatient vs. outpatient costs. As a result, the cost-saving effect of ICOC appear to be much greater in countries where inpatient care costs are substantially higher than the costs of outpatient care.


Solanum (sections Lycopersicon and Juglandifolia) accessions were evaluated under greenhouse conditions after mechanical inoculation with a Jordanian isolate of the new tobamovirus tomato brown rugose fruit virus (ToBRFV). Local and systemic infections were assayed by symptoms evaluation and virus detection via biotests and RT-PCR. All cultivated tomatoes (Solanum lycopersicum) and the great majority of wild tomato accessions proved susceptible to ToBRFV. They showed a wide range of symptoms . Twenty-six accessions representing S. lycopersicum var. cerasiforme, S. pimpinellifolium, S. habrochaites, and S. chilense were tolerant. High levels of resistance have been demonstrated in three accessions of S. ochrantum, a close relative to wild tomatoes (member of the sect. Juglandifolia) not only to ToBRFV but also to the tobamoviruses, tobacco mosaic virus (TMV) and tomato mosaic virus (ToMV). After mechanical inoculation, the three tobamoviruses could be detected only in inoculated leaves in the accessions LA2160, LA2162, and LA 2166, which remained symptomless. However, two other S. ochrantum accessions PI 473,498 and PI 230,519 reacted unusually. They were demonstrated highly resistant to TMV and ToMV, but proved transiently susceptible to ToBRFV showing mild systemic mosaic followed by total recovery from symptoms and the virus.The reaction of 636 The online version contains supplementary material available at 10.1007/s41348-021-00535-x. Solanum lycopersicum) is one of the most important vegetables produced and consumed worldwide ] have been transferred into S. lycopersicum via crossing with wild tomato species. The Tm-1 derived from S. habrochaites  is an incompletely dominant gene that suppresses virus replication , conferring complete dominant resistance based on the hypersensitive reaction of the host plant   and its ability to overcome the resistance genes Solanum (sections Lycopersicon and Juglandifolia) species such as S. arcanum (9); S. cheesmaniae (21); S. chilense (99); S. chmielewskii (10); S. corneliomulleri (26); S. galapagense (11); S. habrochaites (22); S. huaylasense (9); S. juglandifolium (3); S. lycopersicum (81); S. neoricki (16); S. ochranthum (5); S. pennellii (18); S. peruvianum (43); S. pimpinellifolium (256); and S. sitiens (7) were investigated. The following accessions were used as a control: S. habrochaites , S. peruvianum , S. lycopersicum , and the susceptible cultivar S. lycopersicum . The seeds of Solanum species were kindly supplied by the Tomato Genetic Resources Centre , United States Department of Agriculture Agricultural Research Service  and MATE (Hungarian University of Agriculture and Life Sciences). The seeds were sown in fertilized Klasmann Traysubstrate soil, and potted plants were grown in an insect-proofed glasshouse at 24 ± 2 °C temperature, 14/10 h photoperiod, and 50–70% relative humidity.A total of 636 plant accessions belonging to different Nicotiana glutinosa and propagated on N. tabacum cv. Samsun. Inocula were prepared by grinding infected tobacco leaves in sterile 0.01 M phosphate buffer pH 7.0 (1:5 w/v). The sap was then filtered through a cheesecloth, and the extract was stored in aliquots at − 20 C0 for inoculation through this work.A Jordanian ToBRFV isolate (GenBank acc.no. MZ323110) was employed in the present work. Tobacco mosaic virus (TMV-U1) and tomato mosaic virus (ToMV-DH) isolates were received from the virus collection of MATE (Hungarian University of Agriculture and Life Sciences) kindly provided by Pál Salamon. ToBRFV, TMV, and ToMV were transmitted through a single local lesion in N. glutinosa and/or N. tabacum cv. Xanthi-nc as local lesion test plants. All greenhouse and laboratory experiments were carried out in quarantine conditions.For mechanical transmission, virus inoculum was rubbed onto carborundum-dusted lower leaves of young tomato and tobacco test plants. At least 3–10 plants from each accession were inoculated at 3–4 true leaf stage. Local and systemic symptoms were evaluated 3–4 weeks post-inoculation (wpi). In each inoculation experiment, the infectivity of the inocula was assayed using e = class; Re = number of plants in class (e); N = total number of plants.The disease caused by ToBRFV was assessed in each inoculated plant 2–3 wpi, and the disease severity index (DSI) listed Table  was calcSymptomless plants (class 0) confirmed as virus-free by bioassay and RT-PCR were predicted to be resistant. These plants were re-inoculated and tested for the presence of the virus again. Three weeks after the second inoculation, the symptomless plants were decapitated. Two weeks later, two lateral shoots from the decapitated plants were inoculated again and checked for the presence of the virus. Simultaneously, one non-inoculated lateral shoot of each plant was cut off, rooted in MS media, propagated in vitro and transferred to pots. Three propagated individuals were inoculated by TMV, ToMV, and ToBRFV, respectively, and assayed for the presence of tobamovirus by bioassay and RT-PCR.N. glutinosa and N. tabacum cv. Xanthi nc) with leaf extract prepared from inoculated and top leaves of donor tomato plants, respectively. For RT-PCR, RNA was extracted using Promega SV Total RNA extraction kit following the manufacturer’s instructions. Extracted RNA samples were used as a template for complementary DNA (cDNA) transcription oligonucleotide specific for ToBRFV, ToMV, and TMV specific primers. Primer3 computer software (version 4.0.0) was used to design the PCR primers using the ToBRFV (KT383474), ToMV (MH507165) and TMV (FR878069) reference virus genomes. To amplify the coat protein segment, the following primers were used: for ToBRFV F-5894 (5'- GTTCCAAACACAACAAGCTAGA -3') and R-6250 (5'- AAAGTGCATCCGGTTTACAATG -3'), for ToMV F-5894 (5'- GTTTCAAACACAGCAAGCAAGA -3') and R-6250 (5'- CAGACCAACCCAGACATACTTT -3'), and for TMV F-5809 (5'- CTCCATCTCAGTTCGTGTTCTTG -3') and R-6250 (5'- CAAACCAAACCAGAAGAGCTCT -3'). PCR products were detected by electrophoresis in agarose gel .The presence or absence of viruses was demonstrated in leaf samples of inoculated plants using bioassay and reverse-transcription polymerase chain reaction (RT-PCR). Samples were taken at 2–3 wpi from newly developed top leaves. The assayed leaves were rinsed with sodium hydroxide (2%) and then with tap water to avoid virus contamination. Bioassays were carried out by rubbing indicator plants , S. lycopersicum , and S. lycopersicum , showed DSI ranged between 80 and 100%, whereas S. habrochaites  plants showed milder symptoms displaying a DSI of 20%. Plants of 603 wild Solanum accessions were susceptible and showed systemic symptoms at different severity levels , two accessions of S. habrochaites , one accession of S. chilense (LA1932), and four accessions of S. lycopersicum var. cerasiforme  were found to be tolerant showing no symptoms at all or very mild mosaic symptoms with average disease severity between 0 and 20%. The presence of the virus in tolerant plants was confirmed by using RT-PCR and bioassays  at 15 days post-inoculation (dpi) and contained infective virus. However, they recovered from the symptoms . To the best of our knowledge, the last-mentioned six species have never been studied as hosts or non-host of ToBRFV, so they can be indicated as new experimental hosts of this virus.Studying the reaction of 636 accessions of 16 species, we found that most of them were susceptible, including the accessions of .lycopersicum and S.pimpinellifolium . They could be infected by ToBRFV, but did not show any systemic symptoms. A similar tolerant reaction has been identified in SS. ochranthum, a close relative to tomato, varied greatly. Two accessions  showed transitional mild systemic mosaic symptoms followed by total recovery on the new apical leaves. While ToBRFV could be detected by bioassays in the mosaic displaying leaves, no virus was present later on the new symptomless top leaves, indicating either the arrest of virus movement or the very strict control of virus replication. Interestingly, similar recovery from disease, including vanishing of symptoms and lack of detectable viruses, has been already reported in S. ochrantum when inoculated with the potexvirus, pepino mosaic virus  inoculated with ToBRFV remained symptomless both locally and systemically and the virus could be detected only on the inoculated leaves of these plants. These results proved their high level of resistance to ToBRFV. High resistance of S. ochranthum was also found against TMV and ToMV, which suggest the same genetic background of resistance to different tobamoviruses in these plants. Reactions of S. ochranthum have been studied so far to cucumber mosaic virus (CMV) and pepino mosaic virus (PepMV)  or obuda pepper virus (ObPV).In contrast to the accessions PI 473,498 and PI 230,519, plants of three MV) Rick . This isS. ochrantum to ToBRV is difficult due to the sexual incompatibility between S. ochranthum and S. lycopersicum or other closely related tomato species. A potential alternative to surpass this genetic barrier will be the use of somatic hybridization among accessions of these species (Rick The transfer to cultivated tomato of this high level of resistance of ies Rick .Supplementary file1 (XLSX 52 KB)Below is the link to the electronic supplementary material.


The persistence of SARS coronavirus 2 (SARS-CoV-2) RNA on surfaces in public spaces and hospitals and on personal protective equipment (PPE) serves as a potential source for the community transmission of the infection. The RNA can remain in place for a few hours to a few days under ambient conditions. The presence of moderate SARS-CoV-2 protein content in respiratory droplets discharged by infected individuals while sneezing or coughing increases the chances of virus survival on the surfaces of contaminated fomites . HoweverSelf-sterilizing materials possessing photosensitive characteristics offer virucidal effects by the photocatalytic triggering of reactive oxygen species (ROS) that prove detrimental to viruses . SimilarThe utilization of photothermal effects of nanomaterials for self-sterilization applications led to the development of photoactive antiviral masks containing a hybrid nanocoating of shellac/Cu nanoparticles with photocatalytic properties . The coaet al. developed self-cleaning mats based on multifunctional electrospun PMMA nanofibers decorated with silver nanoparticles and ZnO nanorods [The severity of the coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of fabricating and developing advanced protective equipment to minimize virus transmission to frontline workers and health service providers. Karagoz nanorods . The repet al. evaluated the strong electrostatic interactions between anionic photosensitizers on the surface of cationic nanosized cotton fibers for the development of photoinduced nanofabrics that produce ROS on irradiation for biocidal effect [Escherichia coli, Gram-positive Listeria innocua and bacteriophage T7 within 1 h of daylight exposure. Importantly, the high content of cationic sites on the photoinduced nanofabrics improved their interactions with the anionic cell membrane of the microbes, which ameliorated the surface contact to achieve an optimal microbicidal effect. Conversely, the high content of anionic photosensitizers in photoinduced nanofabrics improved their hydrophobicity, which lowered the surface contact with the microbial cell wall, thereby compromising the biocidal efficacy of the fabric. This microbicidal efficacy presents these photoinduced nanofabrics as robust candidates for the development of PPE against microbial infections caused by nanosized aerosol droplets such as SARS-CoV-2.Tang l effect . The polet al. developed daylight-active, vitamin K-containing nanofibrous membranes composed of hydrophobic polyacrylonitrile and hydrophilic poly, which displayed resilient photoactivity for the generation of biocidal ROS [E coli, Gram-positive L innocua and bacteriophage T7. In this study, the nanofibrous membranes appeared to retain their microbicidal efficacy even after repeated exposure to bacteria and viruses, hence indicating excellent reusability and supporting their application as self-sterilizing coating on PPE kits.For appraisal of the reusability of PPE kits coated with self-sterilizing material, Zhang idal ROS . A shortet al., these masks effectively repelled incoming aqueous droplets and demonstrated a photothermal effect when exposed to sunlight [The emerging need for reusable self-cleaning masks has led to the investigation of whether the deposition of layers of graphene on low-melting-temperature nonwoven masks gives them superhydrophobic properties. In a study by Zhong sunlight . The supsunlight .2–organic dye-based, water-repellent air filters by Heo et al. allowed the photochemical inactivation of bioaerosols in the presence of visible light [2–crystal violet nanocomposites created by the researchers triggered the production of ROS to achieve a 99.9% inactivation rate against bioaerosolized Gram-positive Staphylococcus epidermidis and Bacillus subtilis and Gram-negative E coli and Enterobacter aerogenes, with a considerably high filtration efficiency. The hydrophobic barrier provided by the presence of 1H,1H,2H,2H-perfluorooctyltriethoxysilane in the test material granted protection against the inhalation of aerosolized microbes present in damp air. In another study, the photocatalytic properties of TiO2 nanoparticle coatings were reported to inactivate SARS-CoV-2 when exposed to UV radiation [2 nanoparticles generated ROS when briefly exposed to low-intensity UV light, which resulted in oxidative damage to the virus cells. In particular, the excitation of electrons from the valence bond to the conduction band led to the generation of an electron hole, which eventually led to the production of free radicals in the parent solution containing TiO2 nanoparticles. Notably, the TiO2 nanoparticles produced H2O2 in aqueous media, which made their virucidal activity more pronounced in the presence of moisture or humidity. The virucidal effect persisted even in dry conditions. These properties support the approach of coating surfaces with TiO2 nanoparticles to offer self-cleaning properties for preventing transmission of the infection [Advancements in the development of self-cleaning, water-repellant fabrics gave rise to the concept of using these fabrics to filter potentially contaminated air. The development of TiOle light . The ROSadiation . The TiOnfection .2O nanoparticle–graphene-based nanocomposites offer virucidal activity against the influenza virus by preventing its entry to host cells [2O nanoparticles, which affected viral hemagglutinin protein structure and function. These events caused deterioration of the structural integrity of the viral envelope, eventually inhibiting the internalization of virus RNA to host cells to start the infection. The incorporation of this nanocomposite into poly resulted in the formation of transparent films that could be applied on fomites and inanimate surfaces to provide self-sterilizing properties. The 1- to 5-μm Cu2O–graphene nanocomposite incorporating 10 mM poly achieved 70% inhibition of the virus, offering potential application as a coating material on frequently touched surfaces to stop the spread of seasonal viral illnesses.Similarly, transparent surface coatings composed of Cust cells . The nanNanosized covalent coatings based on quaternary benzophenone-based esters and quaternary benzophenone-based amides cross-link on surfaces when exposed to UV radiation . In thisRecent advancements in the development of self-sterilizing materials has led to the discovery of superhydrophobic surfaces that prevent the settling of virus-infected aerosolized respiratory droplets. The rate of drying of respiratory droplets determines the extent of COVID-19 spread, which is fivefold greater in damp air than in dry air, as the extent of relative humidity determines the rate of evaporation of the droplets. The rate of evaporation of aerosolized droplets infected with SARS-CoV-2 increases sevenfold on elevating the humidity from 10 to 90%. The rate of evaporation also depends on the size of the aerosol droplet, which increases by roughly 2 min for a larger drop size . TherefoSelf-sterilizing surfaces possess the unique property of attenuating contacting microbes by inducing redox stress and by photothermal or photocatalytic destruction of the microbial cells. These materials have great potential in combating droplet infection from COVID-19 caused by infected aerosolized droplets that transmit from the patient and settle on the fomites in the vicinity. Surface coating of fomites and inanimate objects with self-cleaning antimicrobial materials serves the purpose of containing the spread of the virus by reducing its survival time or by killing the virus cell machinery, thereby preventing propagation. Self-cleaning surfaces with photothermal or photochemical properties prove effective in virus obliteration when coated on surfaces as thin films, where they display virucidal potency by creating oxidative stress, eventually killing the virus cells. Surfaces with extraordinary hydrophobicity repel aerosolized viral droplets and prove effective as coating material on masks and PPE. Considering the prevalence of so-called second waves of COVID-19 in countries around the world, self-sterilizing materials offer promise in effectively managing spread of the virus in public places and healthcare facilities, where an abundance of inanimate objects serve as sources of virus transmission. The impending self-sterilizing materials must be based on stimuli-responsive virucidal mechanisms with reduced time of action and high efficiency of virus killing. Therefore, self-sterilizing materials could prove highly effective in managing the rising number of COVID-19 cases in second waves.