ERBB2 non-amplified. Endocrine therapy restrains tumor proliferation and is the mainstay of lobular BC treatment. Mutation of ERBB2 has been associated with recurrent ILC. However, it is unknown whether ERBB2 mutation impacts on the otherwise exquisite responsiveness of early ILC to endocrine therapy. We have recently profiled n = 622 HR-positive early BCs from the ADAPT trial for mutations in candidate genes involved in endocrine resistance, including ERBB2. All patients were treated with short-term preoperative endocrine therapy  before tumor resection. Tumor proliferation after endocrine therapy (post-pET Ki67 index) was determined prospectively by standardized central pathology assessment supported by computer-assisted image analysis. Sustained or suppressed proliferation were defined as post-pET Ki67 ≥10% or <10%. Here, we report a subgroup analysis pertaining to ILCs in this cohort. ILCs accounted for 179/622 (28.8%) cases. ILCs were enriched in mutations in CDH1  and ERBB2 , but showed fewer mutations in TP53  and GATA3 . Considering all BCs irrespective of subtypes, ERBB2 mutation was not associated with proliferation. In ILCs, however, ERBB2 mutations were 3.5-fold more common in cases with sustained post-pET proliferation compared to cases with suppressed post-pET proliferation . Moreover, ERBB2 mutation was associated with high Oncotype DX recurrence scores (P = 0.0087). In summary, our findings support that ERBB2 mutation influences endocrine responsiveness in early lobular BC.Invasive lobular breast cancer (ILC) is a special breast cancer (BC) subtype and is mostly hormone receptor (HR)-positive and  Lobular BC is typically hormone receptor (HR)-positive and HER2/ERBB2 non-amplified1. Lobular BC is driven by mutational inactivation of CDH1/E-cadherin and is a slow-growing tumor entity4. Endocrine therapy (ET) restrains ILC cell proliferation and is the mainstay of systemic treatment for lobular BC in the clinic6. Activating mutation of ERBB2 has been associated with recurrent and metastatic ILC and poor prognosis14. Estrogen receptor (ER)-positive human BC cell lines with isogenically incorporated ERBB2 mutation acquire resistance to growth inhibition by estrogen deprivation in vitro15. Accordingly, it is thought that ERBB2 mutation mediates endocrine resistance in vitro15.Invasive lobular breast cancer (ILC) is a special histological BC subtypeERBB2 mutation impacts on the otherwise exquisite clinical responsiveness of ILC cells to endocrine therapy, especially in early ILC. Assessment of the ERBB2 mutation status is not a standard diagnostic procedure in the clinic16. Furthermore, assessment of tumor cell proliferation in early BC pre-treated with endocrine therapy requires that anti-hormonal therapy is initiated a short time before tumor resection. This is not usually done in the clinic. Short-term preoperative endocrine therapy (pET) does not improve outcome, but it offers an empirical readout for endocrine responsiveness by measuring the post-pET Ki67 cell proliferation index19. So far, pET has only been implemented in a limited number of prospective clinical trials, including the POETIC and ADAPT trial22. Whether or not ERBB2 mutation impacts on tumor cell proliferation in early ILC treated with preoperative endocrine therapy has not yet been investigated in this context. Therefore, we extended our previous, retrospective exploratory analyses of BCs from the ADAPT trial (HR-positive/HER2-negative)23. Here we report on the relation between genetic alterations and tumor cell proliferation following pET, with a special reference to ILC and ERBB2 mutation.However, it is currently unknown whether or how much n = 622 HR-positive/HER2-negative early BCs from patients enrolled in the West German Study Group (WSG) ADAPT trial (NCT01779206). This cohort corresponds to a subset of patients enrolled in the ADAPT trial (run-in phase)23. Study design details were reported previously24. Short-term preoperative endocrine therapy  was administered for three weeks before tumor resection22. Oncotype DX recurrence score (RS) testing at baseline was performed at the laboratory of Genomic Health Inc . All tumors were subjected to prospective central pathology review  for histological subtyping and prospective assessment of tumor cell proliferation (documented in 2012–2016). Histologic BC subtypes were determined in accordance with the criteria of the “World Health Organization (WHO) classification of tumours of the breast”, 4th edition (2012)25. Histologic BC subtype calls were based on a consensus of three experts headed by H.K. and were aided by upfront E-cadherin immunohistochemistry (IHC), as described recently26. A comprehensive description of criteria for the diagnosis of ILC has been provided elsewhere2. From an initial set of n = 701 case, n = 79 cases were excluded from further molecular work-up (performed in 2018–2020) due to (i) missing Ki67 values, (ii) unavailable tissue blocks , (iii) divergent histological subtypes at baseline or post-pET or controversial classification as either lobular or non-lobular BC, including cases classifiable as BC with mixed ductal/lobular features (n = 12), (iv) triple-negative hormone receptor status, (v) insufficient DNA amount and/or quality23. The total number of cases for the final statistical analysis was n = 622 .Tumor tissues included rial NCT0779206. T23. BCs scored as HER2 2+ and 3+ were subjected to HER2/ERBB2 fluorescence in situ hybridization in accordance with ASCO/CAP guidelines16. Tumor cell proliferation before endocrine therapy (baseline) and after endocrine therapy (post-pET) was determined prospectively by standardized central pathology assessment of the Ki67 cell proliferation marker23. Immunohistochemical staining of Ki67 was performed with the anti-Ki67 antibody clone 30-9 28. Ki67 scoring was supported by computer-assisted image analysis 30. The Ki67 index was based on three independent evaluations 23. The semiquantitative Ki67 index that was nearest to the digital Ki67 index was accepted as the consensus Ki67 index23. Representative immunohistochemical stainings of BCs in each Ki67 category  are shown in the data supplement 26. E-cadherin IHC was scored as negative (complete loss) versus positive (any specific staining). All IHC stainings were performed on a Benchmark Ultra  automated stainer.Immunohistochemistry (IHC) for estrogen receptor (ER), progesterone receptor (PR) and HER2 was performed prospectively in the central pathology unit of the ADAPT trial as described previously23. In addition, mutational analysis of the CDH1 gene was carried out by next generation sequencing (NGS) using a customized NGS panel, which covered the complete protein-coding sequence including 10 bp of the flanking intron sequence of the CDH1 gene. Mean mapped reads per sample was 282,620 . Data processing and evaluation were performed as described previously23.Extraction of DNA and analysis of genetic alterations were performed (in 2018-2020) as described previouslyP ≤ 0.0500. Statistical analyses were performed with GraphPad Prism software Version 5.00 .For statistical evaluation of the association between genetic alterations and pathologic parameters, we focused on candidate genes with a mutation frequency of ≥2.5%. The two-sided Fisher’s exact test and the Chi square test for trends were used for contingency analyses. The Mann–Whitney test was used to determine statistical significance of different median Ki67 indices in BC subsets. Results were considered as statistically significant if n = 622 HR-positive early BCs from the ADAPT trial for genetic alterations in selected candidate genes involved in endocrine resistance or responsiveness23. All patients were treated with short-term pET (TAM or AI) for three weeks before tumor resection22. Here, we report a subgroup analysis pertaining to the lobular BCs included in this cohort. According to central pathology review, lobular BC accounted for 179/622 (28.8%) cases. ILC was associated with larger pT stage, lower histological grade, lower Oncotype DX recurrence scores, lower baseline Ki67 (before pET), and loss of E-cadherin , and CCND1, FGFR1 and PAK1 23. These genes were selected as candidate genes involved in endocrine tumor response based on the study of Razavi et al., which focused on metachronous BC recurrences after failure of (adjuvant) ET23. For the present subgroup analysis of ILCs we also performed mutational analyses of CDH1. As expected, ILCs were enriched in cases harboring mutations in CDH1   , but showed fewer mutations in TP53  and GATA3      resulting in single amino acid substitutions in the tyrosine kinase domain, such as p.L755S  were exon 20 in-frame insertions or duplications, such as p.Y772_A775dup, which are more common in non-small cell lung cancer (NSCLC) and induce a constitutively active ERBB2 protein conformation (Supplementary Table 33. One ILC (case 110290) harbored two different ERBB2 mutations (p.I767M and p.V777L) (Supplementary Table ERBB2-mutated BCs harbored a concomitant CDH1 mutation (P < 0.0001), confirming the strong association of these two alterations, as reported earlier  Fig. . CDH1 mu8%) Fig. . CDH1 miier Fig. 8. Overal21. Furthermore, post-pET tumor cell proliferation was prospectively determined by standardized central assessment of the Ki67 index in the framework of a controlled clinical trial (ADAPT)21. Moreover, central Ki67 scoring was supported by computer-assisted image analysis23. No such comprehensive information on post-pET proliferation is available for specimens in public BC mutation databases, such as METABRIC or TCGA4. Representative immunohistochemical stainings for Ki67 at baseline and post-pET are shown in Fig. n = 622) revealed that sustained tumor cell proliferation after preoperative endocrine therapy (defined as post-pET Ki67 ≥10%) was associated with TP53 mutation but not with ERBB2 mutation23. In fact, by considering all BCs irrespective of subtypes, ERBB2 mutation was not associated with any prognostic parameter or enhanced proliferation   . This association was also statistically significant in the subset of ILC patients that were treated with AI for pET (Supplementary Table ERBB2 mutations in ILCs were associated with the “high-high” dynamic Ki67 category (baseline and post-pET Ki67 both ≥10%), as defined recently in the POETIC trial (P = 0.0263)   (Supplementary Table ERBB2 mutation was associated with high risk Oncotype DX recurrence scores (P = 0.0087), but only in the subgroup of lobular BCs  Fig. . ConversBCs Fig. .Fig. 4ReERBB2 mutations may arise de novo during endocrine therapy10. In our BC cohort, ERBB2 mutations were concordantly detected in resections specimens (post-pET) and matched core needle biopsies  in 14/18 (77.8%) cases tested . Moreover, ERBB2 mutation was associated with high risk Oncotype DX recurrences scores, but only in the subgroup of lobular BC.In the present study we have extended our previous molecular analyses of BC specimens from the ADAPT (HR-positive/HER2-negative) trial, in which all patients were treated with pET before surgeryERBB2-mutated cases. However, compared with the situation in early HR-positive/HER2-positive BCs, there is a lack of prospective clinical trials designed specifically for early HR-positive and/or ERBB2-mutant ILC. Accordingly, retrospective exploratory subgroup analyses may represent a necessary intermediate step on the way towards new clinical trials for this distinct tumor type.Limitations of the present study include: (i) the retrospective approach of molecular analyses, (ii) the exploratory subgroup analysis for BCs with lobular histology, (iii) exclusion of a small minority of cases with controversial subtype calls  and (iv) the comparatively small absolute number of ERBB2 influences endocrine responsiveness in lobular BC. For the first time, this has now also been demonstrated by means of clinical tumor specimens obtained after pET. Even so, a proportion of ERBB2-mutant ILCs still showed optimal suppression of tumor cell proliferation by pET. Accordingly, it remains an open question whether ERBB2 mutation is a suitable prognostic factor that is independent from other parameters, such as the Onctotype DX recurrence score. Further analyses in larger cohorts treated with adjuvant endocrine therapy alone, or with adjuvant endocrine therapy plus adjuvant chemotherapy would be necessary to clarify this issue. The current retrospective, exploratory subgroup analysis of a proportion of patients enrolled in the ADAPT trial (run-in phase) was not sufficiently powered to address this problem. Second, this subgroup analysis exemplifies that biologically relevant associations may be masked and can remain unidentified, if HR-positive ILCs and non-lobular BCs are lumped together for statistical analyses in BC research. Accordingly, lobular BC deserves greater attention in clinical trials and translational research.In fact, the findings reported here are important for two reasons. First, this study further supports that mutant Supplemental Material


Long-ordered and continuous graphene layers were then embedded into the amorphous SiOC phase. The oxygen-rich SiOxC4−x units were more prone to forming than carbon-rich SiOxC4−x units in SiOC after the introduction of reduced graphene oxide, which we attributed to the bonding of Si atoms in SiOC with O atoms in reduced graphene oxide during the pyrolysis process.Dispersing graphene nanosheets in polymer-derived ceramics (PDCs) has become a promising route to produce exceptional mechanical and functional properties. To reveal the complex nanodomain structures of graphene–PDC composites, a novel reduced graphene oxide aerogel embedded silicon oxycarbide (RGOA-SiOC) nanocomposite was fabricated bottom-up using a 3D reduced graphene oxide aerogel as a skeleton followed by infiltration of a ceramic precursor and high-temperature pyrolysis. The reduced graphene oxide played a critical role in not only the form of the free carbon phase but also the distribution of SiO Proper integration between graphene and PDC is of high practical value, taking advantage of the beneficial properties of both. For instance, adding PDCs to graphene can improve its thermal stability, especially at high temperatures ,2. PDCs 3N4 ) matrix 3N4  or SiC [3N4 . Graphen storage ,9,19. Thronments ,11,17. Aronments .xC4−x (0 ≤ x ≤ 4) tetrahedral structures are surrounded by a fraction of free carbon (Cfree) [However, there are two main challenges in the field of graphene–PDC composites that have not yet exhibited substantial progress. First, controllable dispersion of the graphene nanosheets, especially with high loadings, in the PDCs is extremely difficult using conventional top-down physical mixing or chemical bonding methods due to the strong van der Waals force between the 2D graphene nanosheets. Thus, graphene tends to agglomerate in the PDC matrix, deteriorating the mechanical, electrical, or shielding properties of the composites. The second challenge is that the nanodomain structures of graphene–PDC material systems, which are critical in clarifying structure–property relationships and ultimately in determining their properties for specific engineering applications, are not yet fundamentally understood . Most wo (Cfree) ,22,23. T (Cfree) , while ffree and SiOxC1−x tetrahedral units of reduced graphene oxide embedded SiOC nanocomposites, were investigated using several characterization techniques, including HR-TEM, Raman, XPS, and NMR. The insights into the nanodomain structure of graphene–SiOC composites allow for a greater understanding of structure–property relationships and describe an efficient pathway for designing high-performance graphene–PDCs nanocomposites.In this work, we put forward a universal and delicate bottom-up processing strategy to uniformly disperse graphene into SiOC ceramic by using a 3D reduced graphene oxide aerogel as a skeleton to infiltrate polysiloxane precursors. This strategy has great potential to enable both mechanical reinforcement and multifunctionalization, to which a more controllable design of the geometrical morphology and material constituents is fundamentally attributed. The nanodomain structures, especially CThree-dimensional reduced graphene oxide aerogel (RGOA) was synthesized using a hydrothermal method, followed by freeze-drying and thermal reduction. First, graphene oxide (GO) was prepared according to our previous work  and then3)3OH); RGOA samples (RGOA-600 and RGOA-1000) were then immersed into this solution under vacuum for 2 h to facilitate precursor penetration into the aerogel and eliminate bubbles. Subsequently, the polymeric precursor-loaded RGOA (hereafter denoted as RGOA-600-P and RGOA-1000-P) samples were removed from the solution and freeze-dried for 12 h to remove the TBA. The obtained RGOA-P cylinders were further cross-linked at 250 °C for 2 h and pyrolyzed at 1000 °C for 3 h in a tube furnace under flowing argon at a heating rate of 100 °C/h to obtain the final 3D RGOA-SiOC materials. The obtained ceramic nanocomposite materials after pyrolysis of RGOA-600-P and RGOA-1000-P are denoted hereafter as RGOA-600/SiOC and RGOA-1000/SiOC, respectively. The final weight ratio  of RGOA in RGOA-600/SiOC and RGOA-1000/SiOC was 22.3 and 20.5 wt%, respectively. For comparison, unmodified SiOC material was prepared by the pyrolysis of preceramic polymer H62C at the same heat-treatment conditions.Commercial preceramic polymer precursor methylphenylvinylhydrogen polysiloxane  was infiltrated into the as-prepared RGOA frameworks under vacuum to fabricate 3D graphene-polymer-derived ceramic architectures. We prepared 25 mg/mL polymeric solution by dissolving 100 mg polymeric precursor into 4 mL tert-butanol  at a resonance frequency of 199.13 MHz for 29 29Si using dipole decoupling magic angle spinning (DD/MAS) and high-power 1H decoupling. The powder samples were placed in a pencil-type zirconia rotor with an outer diameter of 4.0 mm. The spectra were obtained at a spinning speed of 8 kHz (4 μs 90° pulses) and a recycle delay of 10 s. The Si signal of tetramethylsilane (TMS) at 0 ppm was used as the reference 29Si chemical shift. The scanning number was 5000. Solid-state 13C CP/MAS NMR spectra were recorded on an Agilent 600 DD2 spectrometer  at a resonance frequency of 150.72 MHz for 13C using cross-polarization (CP), magic-angle spinning (MAS), and high-power 1H decoupling. The powder samples were placed in a pencil-type zirconia rotor with an outer diameter of 4.0 mm. The spectra were obtained at a spinning speed of 10 kHz (4.2 μs 90° pulses), a 2 ms CP pulse, and a recycle delay of 3 s. The C signal of tetramethylsilane (TMS) at 0 ppm was used to reference the [The morphology and microstructure of RGOA and RGOA-SiOC composites were investigated with scanning electron microscopy (SEM) using a Leo Gemini 1530 and transmission electron microscopy (TEM) using a JEOL 2100F. X-ray photoelectron spectroscopy (XPS) was performed on a Thermo Fisher Scientific ESCALAB 250Xi to investigate the surface chemical states of different elements in SiOC and reduced graphene oxide modified SiOC nanocomposites. Raman spectra of RGOA and RGOA-SiOC composites were measured using a micro-Raman spectrometer (RENISHAW inVia) with an excitation wavelength of 532 nm. Solid-state -Three-dimensional reduced graphene oxide aerogels (RGOAs) were prepared from GO and PPy via a typical hydrothermal process at 150 °C for 6 h, followed by freeze-drying for 24 h and thermal reduction at 600–1000 °C for 1 h, as illustrated in The TEM images of SiOC pyrolyzed at 1000 °C a,b show −1 could be attributed to disordered sp2-hybridized modes in the carbon rings and in-plane bond stretching of sp2 carbon, respectively. In addition to the typical D and G bands (at 1320 and 1600 cm−1) in the pure SiOC sample, the 2D, D + G, and 2D’ bands were observed in the second-order Raman spectra at around 2610, 2900, and 3195 cm−1, respectively, which could be assigned to the overtones and combinations of different Raman vibration modes in PDC materials [3 band [4 band was observed as a shoulder of the D1 band at ca. 1190 cm−1 in the spectra of all SiOC, RGOA-600, RGOA-1000, and RGOA-SiOC nanocomposites, which could be attributed to the disordered graphitic lattice (C−C and C=C stretching vibrations and sp2-sp3 bonds) in soot and related carbon materials. The D3 band at 1500–1510 cm−1 could be assigned to the amorphous carbon fractions [Micro-Raman spectroscopy was used to analyze the structure of the carbon phase within reduced graphene oxide aerogels, SiOC, and reduced graphene oxide embedded SiOC samples. aterials . Because [3 band ,28. As sractions .D1/IG) of RGOA, which indicates the reduction degree of graphene oxide, decreased from 1.14 to 1.08 with increasing reduction temperature. This result revealed the removal of defects and recovery of conjugated domains in the reduced graphene oxide, especially at higher thermal reduction temperatures. The extracted ID1/IG intensity ratio can also be used to determine the lateral crystallite size of free carbon . Until now, two correlations between ID1/IG and La have been proposed, as shown in Equations (1) and (2) [0 + λC1 (C0 = −12.6 nm and C1 = 0.033), C’(λ) ≈ 0.55 nm−2. λ is the wavelength of the laser; and ID1 and IG are the intensities of the D1 and G band, respectively.The intensity ratio (I and (2) .ID1/IG La values higher than 2 nm, while the Ferrari–Robertson equation (Equation (2)) is valid for La values lower than 2 nm [2La value is about 1.48 nm, which is theoretically acceptable. However, the TK correlation is more suitable for evaluating the La value of graphene–SiOC nanocomposites, which was 4.63 and 4.81 nm for the RGOA-600/SiOC and RGOA-1000/SiOC samples, respectively.Generally, the Tuinstra and Koenig (TK) correlation (Equation (1)) is valid for carbon clusters with han 2 nm . In the xC4−x units after the introduction of graphene [The elemental composition and chemical environment of C and Si on the surface of the samples were examined by XPS to gain insight into not only the reduction progress of graphene oxide , but alsgraphene . As show4 (103.6 eV), SiO3C (102.8 eV), SiO2C2 (101.8 eV), SiOC3 (100.8 eV), and SiC4 (99.5eV) groups [4, SiOC3, and SiO2C2 units decreased and the content of oxygen-rich SiOxC4−x units (SiO3C and SiO4) increased after the incorporation of RGOA. Especially in the case of lower reduction degrees of RGOA-600, SiC4 and SiOC3 units almost disappeared, and the contribution of SiO2C2 decreased, whereas the proportion of SiO3C and SiO4 increased. These results suggested that RGOA can tailor the structure of SiOxC4-x units in SiOC ceramic by converting the carbon-rich SiOxC4-x units into oxygen-rich SiOxC4−x units  groups . It is w−x units c.29Si MAS-NMR spectroscopy was further used to probe the structure of SiOxC4−x tetrahedra present in the amorphous network of SiOC and RGOA-SiOC nanocomposites. Four different environments were evident in the SiOC sample obtained by pyrolysis at 1000 °C (4 (−110 ppm), SiO3C (−74 ppm), SiO2C2 (−37 ppm), and SiC4 (−12 ppm) structural units [3 (7 ppm) along with SiO4 (−107 ppm), SiO3C (−75 ppm), SiO2C2 (−42 ppm), and SiC4 (−13 ppm) units, as shown in 4 unit decreased, while those of the of SiO2C2 and SiO3C units increased  units due to the interaction between RGOA and SiOC. These interactions caused Si atoms to bond with O atoms from remaining oxygen groups in reduced graphene oxide during the pyrolysis process. The 29Si MAS-NMR spectrum of RGOA-600/SiOC nanocomposite (4 (−110 ppm), SiO3C (−74 ppm), SiO2C2 (−41 ppm), and SiC4 (−10 ppm) units. The relative concentration of SiC4 unit further decreased, and that of SiO4 unit increased. These results further confirmed the interaction between Si atoms of SiOC and O atoms of RGOA and that graphene oxide plays a critical role in the distribution of SiOxC4−x structural units in SiOC. The oxygen-rich SiOxC4−x units are more prone to forming than carbon-rich SiOxC4−x units in SiOC via the modification of graphene oxide, and the lower reduction degree of graphene oxide results in a higher concentration of oxygen-rich SiCxO4−x units. 1000 °C a, which al units ,32, as sal units . Howeverncreased , indicatomposite c obtaine13C MAS NMR spectra of SiOC and RGOA-SiOC nanocomposites. In the case of SiOC sample (3-hybridized carbon within SiOxC4-x units and sp2-hybridized carbon (Cfree), respectively [xC4-x units and carbon bonded to other carbon atoms forming nanodomains of turbostratic carbon, consistent with the findings in a previous work [free, which was present as both turbostratic carbon and graphene sheets and was dominant in RGOA-1000/SiOC and RGOA-600/SiOC nanocomposites  resulted in a higher reduction degree of graphene oxide aerogel with fewer remaining oxygen groups. A novel reduced graphene oxide aerogel containing SiOC ceramic was prepared by the infiltration of a preceramic polymer and a subsequent high-temperature pyrolysis process. The as-prepared RGOA-SiOC presented a highly porous structure with a uniform distribution of graphene into SiOC. After the introduction of RGOA, the carbon-rich SiO


The results indicated that the recovered nanomaterials endure 4 times recyclability retaining up to 89% lead uptake efficiency. To complement the experimental study, DFT calculations were performed to investigate the stability of the formed G–CdO composite compared to CdO NPs; the reactivity of G–CdO compared to plain graphene as well as the interaction insights between graphene and CdO clusters were studied using natural-bond-orbital (NBO), electron-localization-function (ELF) and reduced-density-gradient (RDG) analyses.Graphene-based metal oxide nanocomposites are interesting and promising kinds of nanocomposites due to their large specific area, fast kinetics, and specific affinity towards heavy metal contaminants. In this work, a facile and cost-effective route was used to synthesize CdO nanoparticles (CdO NPs) and graphene-based CdO nanocomposite (G–CdO). The prepared nanomaterials were characterized and explored for lead removal from water. Both CdO NPs and G–CdO composite exhibited excellent sorption capacity of 427 and 398 mg g Graphene-based metal oxide nanocomposites are interesting and promising kinds of nanocomposites due to their large specific area, fast kinetics, and specific affinity towards heavy metal contaminants. Until now, conventional methods to remove heavy metals include coagulation,4 precipitation, chemical reduction,5 ion exchange,6 biological treatment,7 membrane separation,8 and filtration.9 Nevertheless, such techniques have drawbacks such as high cost, low purification efficiency, and difficulty in regeneration. The removal method is regarded as preferable to other methods when it has some features such as low cost, prolonged durability, and simple operation.10 Various materials have been used such as resin,11 carbon,12 zeolites,13 metal oxide,14 clays,15 biopolymers,16 and rice husk.17 However, such materials still have drawbacks because of their relatively low chemical stability and low adsorption capacity for heavy metals. Recently, graphene, single layer graphite, holds great promise for potential applications in many technological fields, especially as an adsorbent for heavy metals owing to its huge surface area, excellent thermal and conductivity due to its unique two-dimensional lattice structure.18 Despite the superior properties of graphene, it has a strong preference for aggregation due to strong van der Waals forces between layers of graphene sheets. Such a drawback inhibits various graphene applications but it can be eliminated by hybridizing graphene with inorganic nanomaterials, especially, with those having a higher surface to volume ratio. Thereby, a composite of graphene with inorganic nanomaterials such as metal oxides can potentially obtain a much-enhanced surface area. Therefore, it has attracted much attention in the scientific community.19 Various metal oxide NPs have been anchored onto graphene sheets' surfaces to act as a stabilizer against the agglomeration of these sheets due to van der Waals forces.20 Graphene-based metal oxide nanocomposites are an interesting and promising type of nanocomposites because of their properties that exceed the properties of their individual phases.21 Also, individual metal oxide nanoparticles still do not have commercial applications due to a strong tendency to aggregate as a result of van der Waals interactions. Such interactions lead to a significant reduction of selectivity and adsorption capacity with prolonged use.22 To overcome these shortcomings, metal oxide nanoparticles are anchored at a supporting surface as graphene, and thereby the size of metal oxide NPs is stabilized on the matrix of the nanocomposite. As a result, the total surface area increases and the adsorption capacity will improve. Moreover, incorporating graphene with metal oxide NPs will prevent the loss of metal oxide nanoparticles due to the stabilization or anchoring of the nanoparticles onto the surface of graphene sheets,23 which makes the application of graphene-based metal oxide nanocomposites becoming increasingly popular in environmental applications.24 In literature, graphene has been hybridized with metal oxides such as Ni/Fe2O3,25 MnO2,26 Fe3O4,27 SiO2,28 ZnO29 to formulate adsorbents for heavy metal removal. Our group designed a facile, cheap, and eco-friendly graphene-based CdO nanocomposites via a green approach.30 Green route synthesis has many great advantages to make it outstanding among all preparation routes to remove heavy metals from aquatic medium.31 Although there are many experimental studies have investigated the potential of graphene-based metal oxides for application as efficient adsorbents for various pollutants, experimental information is not enough to explain the whole picture of the interaction between graphene and metal oxides. In this context, computational chemistry can provide many detailed insights into the interaction between metal oxides and graphene as well as the reactivity and stability of the composite compared to individual graphene. Density functional theory (DFT) as a tool can provide deeper insights to better understand interactions and reactivity in graphene composites.32Pollution of water streams with heavy metals is considered a critical environmental risk all over the world owing to their highly toxic and non-biodegradable nature.ii), reaction time, temperature, pH, and solid dose on Pb(ii) uptake, was studied using batch techniques. The thermodynamic, kinetic, and isotherm studies were performed to elucidate the mechanism of the sorption process. Regeneration efficiency and recyclability were studied as well. The interaction between CdO and graphene will be discussed by DFT calculations as well as the reactivity of formed nanocomposite compared to single graphene towards the removal of lead ions from water.In this study, a graphene–CdO composite was prepared and characterized using various techniques and its adsorption efficiency towards lead removal from the water was explored. The impact of various sorption factors, such as the initial concentration of Pb2·2H2O, 99.5%, ethanol, HCl, HNO3, NaOH and Pb(CH3COO)2 were purchased from LOBA CHEMIE. Hp pencil cores were used as a source of graphite. All chemical reagents were pure and used without purification.Na30 In brief, two graphite pencil cores were installed as cathode and anode electrodes in an electrochemical cell and 1 M Na2SO4 solution was used as a conductive electrolyte. The exfoliation process was applied under 12 volts. The obtained graphene sheets that precipitated as black debris, were washed with de-ionized water, and then sonicated for about 30 min for complete exfoliation. Exfoliated graphene sheets were washed and dried at 60 °C for about 6 h.Graphene was prepared by the electrochemical exfoliation method.Red onions (100 g) were sliced, and dipped in aqueous ethanol (50 : 50 v/v), for 2.5 days. Then the onion residue was removed and the solution was stored at 20 °C for further use.3COO)2·2H2O solution was added to about 300 mL extract under stirring. A yellow precipitate was formed immediately. The reaction solution was aged for 24 h at room temperature and pH 5.5 and then centrifuged and washed several times with deionized water and then ethanol. Afterward, the obtained material was dried at 60 °C then calcined at 400 °C for 2 h.3050 mM of aqueous Cd, UV-Vis spectrophotometer , X-ray diffractometer (Philips – PW1710), transmission electron microscopy – TEM; (JEOL – JEM-100 CXII), scanning electron microscopy – SEM; (QUANTAFEG 250 with energy-dispersive X-ray spectroscopy – EDX attachment) and Raman spectrometer (WITEC Alpha300 laser) were utilized.ii) solutions with initial concentrations of 550 mg L−1 at pH 4.8 and the residual lead ions concentration was measured (at time = 0–24 h) using an ICP-OES . For the thermodynamic studies, 0.025 g of nanoadsorbent was added to 25 mL of 550 mg L−1 Pb(ii) solution at pH 4.8 for 24 h at various temperatures (25–37 °C). The pH during the sorption experiments was regulated by dropwise addition of 0.1 M HNO3 or 0.1 M NaOH.All tests were performed at 29 °C using 25 mL of lead ion solution in a batch mode. The effects of pH (1.55–7.02), nanoadsorbent dose (0.015–0.03 g), and lead initial concentration (25–1500 mg) on the sorption behavior were studied. The kinetic study was performed by adding 0.025 g of nanoadsorbent to Pb(ii) ions to investigate the service life of nanomaterials and % removal.Specific amounts of lead-loaded nanomaterials were eluted with dilute hydrochloric acid solution and then washed until the pH was neutral. Hence, the spent materials were dried at 75 °C to constant weight, and then re-loaded with Pb and the percent removal or uptake (R%) of lead ions at equilibrium were calculated using C0 and Ce (mg L−1) are the lead concentrations in the liquid phase before and after adsorption, respectively. V (L), t (min), and m (g) are the volume of the liquid phase, time, and mass of the dry nanoadsorbent used, respectively.The sorption capability (33qe and qt are the Pb(ii) concentration of sorbed by nanomaterial (mg g−1) at equilibrium phase and predetermined time interval t, respectively. K1 is the pseudo-first-order rate constant (min−1).The results of adsorption kinetic experiments were studied by four models: the pseudo-first- and second-order, intraparticle, and Elovich models. Pseudo-first-order, 34K2 (mg g−1 min−1) is the rate constant of the pseudo-second-order. Another model is Elovich, which is symbolized as 35α is the initial adsorption rate parameter of lead ions (mg g−1 min−1) while β (g mg−1) is Elovich constant correlates activation energy and the surface coverage included in chemisorptions.The pseudo-second-order kinetic model, 36Kint (mg g−1 min−1/2) is the rate constant of the model. Values of C describes the boundary thickness. This means the larger is the intercept (C), the greater is the effect of the boundary layer in the solution. The values of Kint (slope) reflect the sorption rate of lead ions onto the nanomaterial surface.The intraparticle diffusion equation is expressed as 37qL is the maximum sorption capability (mg g−1) of nanomaterial adsorbents and KL is a constant (L mg−1) describing sorption affinity for the nanoadsorbent. The basic characteristic of that model could be described in terms of a dimensionless factor, RL, which is expressed as Cmax is the highest Pb(ii) concentration.After completion of adsorption isotherm tests, four models, Langmuir, Temkin, Freundlich, and Dubinin–Redushkevich (D–R) were applied to depict all isothermal features of G–CdO nanoadsorbent. The four models can be written (linear form) as in 38 and defined as KF parameter, (mg g−1) (L mg−1)n1/ is a constant corresponding to the Pb(ii) multilayer sorption capacity. The constant n is defined as the heterogeneity factor.Freundlich describes a heterogeneous surface of nanoadsorbentii) sorption is gradually reduced linearly with surface interaction39 and the linear form is better for the sorption process rather than the logarithmic, A (L g−1) is the Temkin isotherm equilibrium binding constant while B corresponds to equilibrium adsorption heat. The gas constant is R (J mol−1 K−1) and the absolute temperature is T.Temkin isotherm model depicts that the heat of Pb−1/2), while ε (J mmol−1) is Polanyi potential defined as The D–R isotherm was approached from the following G0, kJ mol−1), standard entropy (ΔS0 J K−1 mol−1), and standard enthalpy  as:Kd represents linear sorption coefficient, defined as a ratio between the surface concentration of adsorbed Pb(ii) and its concentration in the solution at equilibrium.The data of the thermodynamic experiments were analyzed to get the change in free energy  and affinity (A) are written as:All computational calculations were performed on a personal computer and Gaussian 09W program package. The B3LYPμ), global hardness (η), electronegativity (χ), electrophilicity index (ω), index of softness (σ), maximal charge acceptance (ΔNmax) and energy change (ΔE) are stated as:Global potential (E2) were calculated using the NBO 5.9 software (in Gaussian) at level DFT/B3LYP/LANL2DZ of the theory to determine importantly donor–acceptor interactions in the G–CdO complex. Multiwfn, Gauss Sum and VMD programs were also used at the same level of theory.The interactions between graphene and CdO in the formed composite were explored using natural-bond-orbital (NBO) analysis, electron-localization-function (ELF) and reduced-density-gradient (RDG) analyses. Perturbation delocalization or stabilization energies of second-order (−1), C–H (at 2924 cm−1), C PBM data was replaced with SVG by xgml2pxml:<glyph-data id="z.dbd" format="PBM" resolution="300" x-size="8" y-size="10" xml:space="preserve">00000000000000000000000000000000111111110000000011111111000000000000000000000000</glyph-data><svg xmlns="http://www.w3.org/2000/svg" version="1.0" width="13.200000pt" height="16.000000pt" viewBox="0 0 13.200000 16.000000" preserveAspectRatio="xMidYMid meet"><metadata>Created by potrace 1.16, written by Peter Selinger 2001-2019</metadata><g transform="translate scale" fill="currentColor" stroke="none"><path d="M0 440 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z M0 280 l0 -40 320 0 320 0 0 40 0 40 -320 0 -320 0 0 -40z"/></g></svg>C (at 1634 cm−1), and C–O (1090 cm−1). Onion extract spectrum showed peaks attributed to O–H and N–H at 3440 cm−1, C–H asymmetric at 2928 cm−1, carbonyl vibration at 1636 cm−1, CC aromatic at 1425 cm−1, and C–O at 1055 cm−1. These data reflected the complex nature of the extract derived from polyphenols, carbohydrates, proteins, and lipids. For the prepared nanomaterials spectra, a similarity is displayed with slight changes in intensities or positions, which depict the presence of onion organic species as capping and complexing agents. The Cd–O vibrational stretching appears at 603 and 556 cm−1 in composite and single cadmium oxide spectra, which affirms the formation of nanomaterials.The FT-IR spectrum of graphene, UV-vis absorptions, θ = 33.01, (200) at 2θ = 38.33, (220) at 2θ = 55.34, (311) at 2θ = 65.8, (222) at 2θ = 69.31 and (400) at 2θ = 82.03 the cubic structure of CdO (JCPDS 65-2908). The XRD analysis of graphene showed an intense peak at 26.56° related to the (002) plane that confirms the exfoliation of graphite into graphene layers. The XRD analysis of G–CdO is similar to both hybrid CdO NPs and graphene reflect the anchoring of CdO nanoparticles onto the nanosheets of graphene. The mean particle sizes calculated from the Scherrer equation were 21.94 and 26.09 nm for CdO and G–CdO, respectively. The peak sharpness of the prepared nanomaterials indicates their high crystalline nature. Such finding is harmonious with the SEM analysis, The XRD analysis, shown in The TEM analysis of CdO NPs and G–CdO are shown in −1 (D-band) and 1585 cm−1 (G-band), attributed to a primary in-plane vibration of k-point phonons belonging to A1g symmetry and first-order in-plane stretching vibration belongs to E2g phonon from sp2 carbon rings, respectively.42 The Raman spectrum of G–CdO shows a clear redshift for both D and G peaks by 10 and 8 cm−1, respectively, which confirm the anchoring of CdO on the graphene surface. The intensity ratio (IG/ID) usually measures the degree of defects in the graphene system.43 The calculated IG/ID ratio was increased from 1.03 (G) to 1.08 (G–CdO) implies a high degree of defects. This finding adds to the proof that the G–CdO composite was formed.To provide additional evidence on G–CdO formation, Raman analysis was carried out for the prepared graphene and G–CdO nanocomposite. Raman spectroscopy is an effective tool to distinguish ordered and disordered carbonaceous materials. The spectrum of graphene shown in ii) ions for 24 h contact time at 550 mg L−1 as an initial lead concentration and solid/liquid ratio of 1g L−1. The highest adsorption capacity was noted for the G–CdO nanocomposite compared to CdO NPs and graphene, which may be attributed to the synergistic effects of CdO NPs and graphene. The adsorption capacity of the graphene was found to be the lowest in an acidic medium and increased with increasing solution pH. As seen in ii) and graphene rings. Besides, the chelate formation of Pb(ii) with CdO that decorated the graphene surface could have been involved. However, as moving from acidic to a neutral solution, the interaction with lead ions is favorable, resulting in the enhancement of the removal capacity until Pb(ii) ions tend to hydrolyze.44 Owing to the subsequent hydrolysis and precipitation of lead ions in basic solution, the pH of the medium was set to 4.8 for all experimental studies to avoid Pb(ii) precipitation.2+ adsorption. Hence, different doses of nanoadsorbents were used for the lead removal. As shown in ii) adsorbed layer at the adsorbent surface. Again, the removal efficiency was higher for G–CdO nanocomposite followed by CdO NPs.The amount of nanoadsorbent affects the rate of Pb−1, the sorption capacities almost remained constant. This is possibly attributed to the lack of adequate active sites to accommodate additional Pb(ii) ions. The maximum lead adsorption capacities for G–CdO, CdO NPs, and G are 400, 370, and 67 mg g−1, respectively.The influence of lead concentration on the removal capacity of prepared adsorbents is displayed in ii) concentration reached 200, 100, and 50 mg g−1 for G–CdO, CdO and G, respectively. During the increase in initial lead concentration, the surface areas of the three nanoadsorbents available for the removal are insufficient, hence, the rate of lead removal decreases with increasing lead concentration. At lead concentration = 200 mg L−1 for G–CdO, 100 mg L−1 for CdO NPs and 50 mg L−1 for graphene, equilibrium was attained since all the adsorption sites on the surface of the nanomaterials were bonded by lead ions. As illustrated in The lead removal% for three prepared nanoadsorbents, shown in R2, the kinetics data of lead adsorption onto G, CdO and G–CdO were better supported by the pseudo-second-order model than by other models, as shown in R2 > 0.990). Deviation from linearity for the rest models reflects the lack of fitting of these models to the experimental kinetic data.Kinetics parameters were calculated and are shown in −1 for G–CdO, CdO NPs and G, respectively) were very close to the calculated values . This finding indicates that the pseudo-second-order model can accurately express lead adsorption onto prepared nanomaterials.In general, the pseudo-second-order model was employed to represent chemisorption, with ionic force relating to the electron sharing or exchange between the lead cations and nanomaterial as covalent interaction, and ion exchange. As a result, the chemisorption process governed the rate of lead removal by G, CdO and G–CdO. Furthermore, it was found that the experimental values of adsorption capacities . Adsorption is either favorable (0 < RL < 1), linear (RL = 1), unfavorable (RL > 1), or irreversible (RL = 0) based on the RL value. The better-fitting Langmuir isotherm model suggested the homogenous adsorption of lead cations with all adsorption active sites of equal affinity. The separation factor, RL, values determined from the Langmuir model for lead removal were in the range of 0.095–0.018 suggesting that the removal process was favorable. The Langmuir monolayer adsorption capacities for lead removal systems increased from 79 mg g−1 (for G) to 427 mg g−1 (for G–CdO), demonstrating that the modified G–CdO is capable of removing lead from the aqueous solution.Dubinin–Redushkevich, Freundlich, Langmuir, and Temkin sorption isotherms were utilized to clarify the lead removal mechanism. Calculated results from various adsorption isotherms, n, for the adsorption of lead are higher than 1, indicating that the uptake process was favorable. Therefore, the uptake of lead ions by G–CdO, Cd NPs and graphene surface proceed with some heterogeneous inactive sites.From B and A, −1, 10.4 J mol−1 and 59.5 L g−1 and, 1.76 J mol−1, respectively) than graphene  indicating that the heat of sorption refers to a physical process.According to the calculated Temkin parameters E in Although the Dubinin–Redushkevich model does not fit the sorption process, the values of ii) cations compared to various nanoadsorbents  in-depth, typical thermodynamic parameters were determined. For pristine graphene, the calculated parameters in H0 < 0) reaction.1 The negative ΔS0 suggests a decrease in the randomness in the graphene/Pb(ii) system during the removal process. Positive values of ΔG0 under various temperatures denoted that the reaction was a nonspontaneous process.1 The same finding was reported for the adsorption of Pb(ii) by reduced graphene oxide.49 From G0 value for both CdO and G–CdO adsorbents are negative indicating that the two reactions are a spontaneous and thermodynamically feasible process. As illustrated in H0 are positive.To investigate the sorption process of Pb solution interface increased as the process progressed. The values of ΔH0 were ranged from 37 to 43 kJ mol−1, illustrating a physisorption reaction.In a similar work, Ren To complement experimental results, DFT calculations were performed to respond to three questions: (1) the stability of formed G–CdO nanocomposite compared to CdO, (2) the reactivity of the composite compared to plain graphene and CdO, and (3) the interaction insights between G and CdO clusters in the prepared composite. For easy calculations, a dimer of CdO cluster was considered and a graphene sheet was built as a hexagonal pattern with 7 benzene rings (24-C atoms). CdO was added to the graphene sheet at the central benzene ring. Egap for CdO, G, and G–CdO systems are demonstrated in 51 Also, an increase in Egap from 1.896 eV (CdO) to 2.182 eV (graphene–CdO complex) has been recorded due to the interaction. Such an effect suggests that the formed G–CdO complex is more stable than isolated CdO nanoparticles.52 The calculated dipole moment (DM) at the same level of theory for the G–CdO composite was found to be 3.97 Debye compared to 0 Debye for single G and CdO systems. The dipole moment is an important electronic property that measures the charge distribution asymmetry and the intermolecular interactions inside the molecule. The difference in electronegativity between Cd atom (1.69) and C atom (2.55) leads to induce a charge transfer from the Cd atom to the sheet, which in turn induces the dipole moment. Accordingly, the energy change in the electron transfer of the G–CdO composite decreased to −8.516 e. V, which indicates that the charge transfer interaction is energetically favorable (as ΔE < 0). In the same context, the value of ΔNmax (=3.623 eV) emphasizes the presence of intramolecular charge transfer within the composite, which elucidates its reactivity. When the ratio (ΔE/ΔNmax) = 0 this means the compound is saturated with electrons and no charge transfer occurs. The calculated total electron energy of the ground state for the G–CdO complex is −31 789.8 eV showing minimum total energy among all three systems (−25082.1 eV for graphene and −6707.2 eV for CdO).To characterize the chemical stability and reactivity of the G–CdO complex, the energies of electronic parameters; HOMO, LUMO and their electronic gaps, I, and affinity properties A are so important to calculate the absolute hardness η and the electronegativity χ. The CdO has the largest absolute affinity value, so that will be a better electron acceptor during the interaction with plain graphene, which will be the electron donor. G–CdO has the lowest potential ionization value of 5.042 eV, so it is a better Lewis base (electron donor). Thus, according to DFT calculations, G–CdO is predicted to have a % removal efficiency for lead ions higher than individual graphene and CdO. The global electrophilicity index (ω) is a measure of energy lowering during accepting electrons. The electrophilicity value of G–CdO was the lowest, which strengthens its ability to act as an electrophile compared to single graphene and CdO. Therefore, the G–CdO composite is speculated to bind with lead ions and act as a nucleophile more than plain graphene and CdO systems.As listed in 53 and demonstrated in For a better understanding of the deposition of CdO onto graphene sheets and its effect on the electronic properties of the formed composite, the total and partial density of states plots of the G–CdO complex was calculated and analyzed. The energy gap and energy level for both graphene and graphene–CdO molecules have been demonstrated in 54 The MEP plots at G and G–CdO surfaces are represented in ii) would preferentially attack G–CdO at oxygen positions. The yellowish color near localized at the pi system of graphene represents the area of less electrophilicity of the compound as compared to oxygen atoms, while the blue regions of the composite are spread on the cadmium atoms. The MEP contour map of G–CdO confirmed that oxygen atoms are electrophilic sites to remove cationic Pb(ii) ions, It initially used to predict relative reactivity. It is the total interaction of the net charge distribution (electrons + nuclei) with partial charges, dipole moments, reactivity sites and electronegativity of a compound. Also, MEP explains the relationship between the structure and reactivity in molecule.E2 resulting from the second-order Fock-matrix analysis. Therefore, the greater extent of donor–acceptor interaction and conjugation the greater is the values of E2 and the charge transfer between the orbitals (filled and empty) of the whole system. Such interaction leads to a decrease in the occupancy from the idealized Lewis structure (lone pair or bonding) to a non-Lewis virtual orbital (anti-bonding or Rydberg). The most important interactions between Lewis type and non-Lewis type NBO along with, E2, their stabilization energies are calculated and listed in Table S1.−1, respectively. Other significant intramolecular interactions are from LP*(6)Cd38 to LP*(8)Cd37 corresponds to stabilization energy 87.7 kJ mol−1. The charge transfer from LP*(1) C4 to BD*(2) C5–C6, from LP (1) C13 to BD*(2) C11–C12 and from LP*(1) C33 to BD*(2) C30–C35 corresponds to 84.64, 82.26 and 82.16 kJ mol−1, respectively. Such results match well with those previously conducted after optimization and correlate with the fatal function of density donation during the anchoring of CdO onto graphene sheets. However, the graphene system could also accept electronic sharing from Cd atoms via the back-donation process besides its tendency to give electrons.Natural bond orbital (NBO) analysis is an efficient way to explore inter-and intramolecular bonding within the molecule such as charge transfer or conjugative process, charge distribution and donor–acceptor interactions. This analysis investigates the relationship between the filled NBOs (donors) and virtual or empty NBOs (acceptors). Such interaction is proportional to the stabilization energy ρ(r) and its derivatives to analyze the various kinds of intermolecular forces and can be expressed as:The RDG analysis is a non-covalent intermolecular identification and visualization tool. It is a dimensionless function based on the density λ2) of the Hessian matrix and ρ(r) in each point of the isosurface as it equals to the product of ρ and signs of λ2.55 Each specific value of RDG on the Y-axis has a region on the X-axis that can be classified into three types, strong attraction corresponds to sign λ2(r)ρ(r) < 0, strong repulsion corresponds to sign λ2(r)ρ(r) > 0 and weak interaction corresponds to sign λ2(r)ρ(r) ≈ 0. Therefore, to study the non-covalent reaction within the G–CdO composite, the RDG(r) vs. sign(λ2)ρ(r) function plot (scatter graph) is investigated at low gradient regions and is compared to the G scatter graph, λ2(r)ρ(r) > 0 due to the steric clash in the ring structures. The RDG scatter graph of G–CdO, λ2(r)ρ(r) > 0 indicating a steric interaction inside the graphene rings, as elucidated in the G scatter graph. In addition, the spike at negative density values indicates the attractive stabilizing dipole–dipole interaction due to the binding of CdO onto the G surface. To visualize the non-covalent interaction locations, λ2(r)ρ(r) value. The red regions show destabilizing repulsive steric nonbonding positive clashes while the blue region depicts the negative attractive dipole–dipole forces. The green region with values close to zero indicates weak dispersion-stabilizing interactions such as π stacking and van der Waals interactions. The obvious significant changes in the G isosurface features after the interaction with CdO indicate that the graphene/CdO interactions were strong and the system displays strong van der Waals interactions. Therefore, the RDG analysis is in good agreement with that conducted with NBO analysis.There is a direct correlation between the magnitude of the intermolecular interactions and both second derivative eigenvalue  mean regions with delocalized electrons, while high ELF values (>0.5) describe domains with localized bonding and antibonding. Domains with perfect localization take the value of 1. n = 8) was performed to evaluate the precision of removal. The precision expressed as percentage relative standard deviations (% RSDs) was 1%, The intra-day repeatability  metal is still more than 89.6% after repeated four cycles, indicating that the prepared nanomaterials have good recyclability as adsorbents. Thus, the surface of the nanoadsorbent under investigation gained positive charges and Pb(ii) ions almost desorbed into the acidic solution, indicating that the mechanism of ion exchange may be included in the sorption reaction. It can be concluded that, significantly, graphene-based CdO nanocomposite shows reusability and durability properties even after 4 regenerations. The marked regenerability of G–CdO can be assigned to its stable structure, facilitating its application in environmental treatment as no cadmium was detected in the solution, demonstrating that the nanocomposite was stable under the employed experimental conditions.The two most pivotal features, which a good adsorbent should show are reusability and durability. To assess the possibility of regeneration and reusability of prepared nanomaterials as adsorbents, desorption experiments were carried out with 0.1 N HCl as an eluent and pH kept >2 to prevent leaching of CdO out of graphene. After extraction in an acidic medium, the recycled G–CdO was washed and reused again. The impact of four consecutive adsorption–desorption cycles was studied, The mechanism of lead uptake onto nano G–Cd composite is based on the adsorption isotherm and kinetics data discussed previously, as well as experimental FTIR data shown before and after the lead adsorption process.G–CdO and CdO were successfully prepared using reducing and stabilizing agents present in the onion extract. FTIR analysis of the onion extract and nanomaterials is similar to some shifts due to the capping of nanoparticles with onion compounds. Thus, CdO NPs induced the coating of graphene sheets with many organic moieties. Also, FTIR confirmed the covalent bonding between graphene sheets and the modified CdO surface, while the SEM/TEM images showed the CdO NPs anchored at the surface of graphene sheets.−1 (stretching vibration of H-bonded and N–H bond) and 1634 cm−1 (carboxylic) decreased and shifted after lead adsorption, −1 appeared.56 The above analysis revealed the reduction of N–H and H-bonds in the functional groups and the replacement of lead ions in these active sites during the adsorption process. Similar results have been reported47 and confirmed a mechanism based on the formation of complexes or ion exchange with organic groups that wrapped nanomaterials. In the other work, Zhang et al.57 confirmed that both amine and carbonyl/hydroxyl groups within N doped adsorbent are responsible for lead adsorption. Li et al.57 used a polydopamine and MnO2 coating to remove Pb(ii) ions and they observed that the N contained groups in polydopamine also bind with lead ions. Besides, they have conducted that both amine and carbonyl/hydroxyl groups contribute to lead uptake through chelation. ii) from the environment.To study the mechanisms of as-prepared nanoadsorbents for Pb removal, an FTIR study was carried out. Comparing the FT-IR analysis before and after adsorption, it was found that the intensities of the peaks at around 3440 cm−1, respectively. Pseudo-second order kinetic model and Langmuir isotherm explained the process. The thermodynamic studies were conducted through spontaneous, physical, and endothermic sorption reactions. The experimental results of %lead removal matched well with the DFT theoretical study of the nanocomposite tested. The energy of the perturbation of the Fock matrix depicted strong intramolecular interactions. Various kinds of donor Lewis–acceptor and non-Lewis interactions play a great function in composite stabilization. The RDG analysis is in good agreement with that conducted with NBO analysis as a significant change in the G–CdO isosurface features after the interaction with CdO indicates that graphene/CdO interactions were strong and the system displays strong van der Waals interactions. Also, the study confirmed that the uptake of lead ions onto prepared nanomaterials was mainly attributed to the electrostatic attraction forces and surface complexation. Additionally, CdO NPs and G–CdO composites could be regenerated and used repeatedly at least four times without significant loss in performance, allowing the as-prepared nanoadsorbents to be potentially applied to in situ lead removal from aqueous solutions.CdO NPs and G–CdO composite were prepared and characterized. Results of FT-IR, SEM, EDX, TEM, XRD, UV-Vis analyses demonstrated that CdO NPs and G–CdO composites were successfully synthesized. Taken together, the integration of graphene and CdO NPs created a novel nanomaterial that potentially removes lead from an aqueous solution. The results of the batch adsorption experiments implied that the maximum adsorption capacities of CdO and G–CdO were 398 and 427 mg gThere are no conflicts to declare.RA-011-D1RA04754J-s001


R2 = 0.973), which were far superior to their QCM counterparts. The underlying mechanism was revealed and discussed.Humidity sensors with comprehensive performance are of great interest for industrial and environmental applications. Most sensors, however, have to compromise on at least one characteristic such as sensitivity, response speed, and linearity. This paper reports a gravimetric humidity sensor based on a capacitive micromachined ultrasonic transducer (CMUT) with exceptional all-around performance, and presents a side-by-side comparative investigation of two types of gravimetric humidity sensors for a better understanding of their characteristics and sensing mechanisms. For these purposes, a circular CMUT and a quartz crystal microbalance (QCM) with a resonance frequency of 10 MHz were designed and fabricated. Poly (PVA) was employed as the humidity sensing layer for its hydrophilicity and ease of film formation. The electrical properties of the sensors, including the electrical input impedances and quality factors, were characterized by a vector network analyzer. The relative humidity (RH) sensing performance of the sensors was evaluated and compared from RH levels of 11% to 97%. Both sensors exhibited good repeatability and low hysteresis. The unique microscale resonant structure of the CMUT humidity sensor contributed to a high sensitivity of 2.01 kHz/%RH, short response and recovery times of 8 s and 3 s, respectively, and excellent linearity ( Humidity detection plays a crucial role in various applications, including environmental control and industrial processing ,2. For eGravimetric sensors are widely adopted for humidity sensing due to their high sensitivity and fast response. They work by converting the mass change of water molecules into the shift of the resonance frequency. The quartz crystal microbalance (QCM) is the most popular of the gravimetric sensor types for its maturity, low cost, and capability of detecting mass changes down to the nanogram level ,7. The aIn recent years, an attractive candidate for humidity sensor platforms, the capacitive micromachined ultrasonic transducer (CMUT), has emerged to compete with QCMs. As another type of gravimetric sensor, CMUT is developed from micro-electro-mechanical system (MEMS) technology . Hence, In most situations, a more competitive humidity sensor is the one that has comprehensive performance of sensitivity, repeatability, linearity, response speed, and hysteresis. This requires the sensor and the functional material to work synergistically. Poly (PVA) is a low-cost, non-toxic, and biodegradable polymer with outstanding mechanical and film-forming properties, chemical and thermal stability, and water-solubility . These fAs an increasing number of chemical sensors are emerging, comparative studies are necessary for a better understanding of their characteristics and sensing mechanisms. Robinson et al. compared capacitive- and resistive-based transduction mechanisms using single-walled carbon nanotubes , and conIn this paper, we developed a high-performance CMUT-based humidity sensor and presented a side-by-side comparison with a QCM counterpart to provide more insights into the two types of gravimetric sensors. The CMUT and QCM humidity sensors based on the PVA active layer were designed, fabricated, and characterized. The RH sensing properties of the two sensors, including the sensitivity, linearity, reproducibility, repeatability, response speed, and long-term stability were experimentally studied and compared. The underlying mechanism that caused the distinct sensing characteristics was revealed and discussed.As presented in Here, a 10 MHz AT-cut QCM with silver electrodes was derived from Wuhan Hitrusty Electronics Co., Ltd.,  the photograph of which is shown in 3N4) was selected as the membrane material due to the fabrication process. Consequently, the structural parameters of the membrane governed the resonance frequency of the device. As the resonance frequency was designed as 10 MHz, the thickness and radius of the membrane were determined accordingly to be 520 nm and 15 μm, respectively. A 100 nm thick electrode layer was deposited on the top of each membrane. The cavity depth was designed to be 180 nm to allow free vibration of the resonant membrane. The insulation layer was designed as 450 nm to avoid breakdown of the device. The CMUT was composed of 5380 units connected in parallel.A 10 MHz circular CMUT was designed for comparison with the commercial QCM. The diameter of the CMUT was designed to be 3 mm, which ensured the fabrication yield and was also close to that of the QCM electrode for a relatively fair comparison. The resonance frequency of the CMUT is determined by :(1)fc=0.2) layer. The substrate was then bonded in a vacuum with a silicon-topped wafer, which was deposited with an LPCVD Si3N4 layer on both sides. Subsequently, the resonant nitride membrane was released by removing the backside nitride layer and the silicon handling layer on the top wafer. After exposing the bottom electrodes, Cr/Al metal electrodes and contact pads were deposited and patterned. 3N4 membrane, the SiO2 insulation layer, and the silicon substrate can be identified in the image.The CMUT was fabricated by the MEMS fabrication process based on the nitride-to-oxide wafer bonding technique . To starThe PVA powders with a viscosity of 54.0 mPa·s were derived from Sinopharm Chemical Reagent Co., Ltd., . Then, 10 mg of the PVA powder was dispersed in 19.99 g ultrapure water and stirred by a magnetic stirring bar at 90 °C for 3 h until the powders were completely dissolved. Afterward, the dispersion was left at room temperature for 12 h for cooling down and degassing. Then, 7 μL of the 0.05 wt% PVA dispersion was drop-casted on the surface of the CMUT and the QCM, respectively. Lastly, the sensing films were dried by baking at 60 °C for an hour.11 parameters of the sensors were measured by the VNA and converted to electrical impedances and admittances.The surface morphology of the PVA layers on the CMUT and QCM sensors were examined by SEM . The electrical properties of the sensors were characterized by a vector network analyzer (VNA). As the CMUT requires a bias voltage to bring its resonating membrane close to the substrate for higher efficiency, it was biased at 35 V by a DC power supply  and connected to a streamline USB VNA  through a bias tee, while the QCM was directly connected to the VNA. The S3COOK, MgCl2, K2CO3, NaBr, NaCl, KCl, and K2SO4, respectively [The humidity sensing measurements were conducted by monitoring the sensors’ frequency changes while alternating the RH environments at room temperature. RH levels of 11%, 23%, 33%, 43%, 58%, 75%, 84%, and 97% were generated by saturated salt solutions of LiCl, CHectively . Figure From Generally, a high quality factor of 300–500 is achievable by the CMUT despite the massive parallelism , becauseReproducibility, Sensitivity, and LinearityIt is known that both the CMUT and the QCM sensors rely on the detection of resonance shifts in response to the loaded mass equation :(3)Δfq=−From Equations (2) and (3), the theoretical mass sensitivity of the CMUT was calculated to be 4.2 Hz/fg, which was six orders of magnitude higher than that of the QCM (1.15 Hz/ng). Within the RH level of 58%, however, it is observed from From Dynamic response and hysteresisResponse/Recovery time and RepeatabilityThe dynamic frequency responses of the CMUT and QCM sensors were evaluated as the RH switched between 11% and 84%. The repeatability of the sensors was examined by switching the RH from 11% to 58%, 75%, and 84% for five cycles. As shown in Temperature dependence and long-term stabilityIt is well known that the properties of semiconductors and quartz are temperature-dependent. Therefore, the temperature dependence of the CMUT and QCM sensors was studied. The long-term stability of the sensors was investigated by measuring their frequency shifts in different RH environments a few times over 45 days. This work reports a high-performance CMUT-based humidity sensor using PVA as the sensing film. In addition, to the best of our knowledge, this work provides the first side-by-side comparative study of the CMUT and QCM sensor platforms. The two types of gravimetric humidity sensors were designed and fabricated. Their electrical properties were characterized by a VNA and the humidity sensing performance was examined over a wide RH range from 11% to 97%. Although the working principles of both sensors were based on the mass-loading effect, the QCM worked as a single element while the CMUT involved massive parallelism, which led to a huge difference between their effective oscillation areas of four orders of magnitude. Consequently, a considerable discrepancy between their RH sensitivity and theoretical mass sensitivity was observed. Despite the small effective oscillation area of each unit, the CMUT humidity sensor exhibited a high RH sensitivity of 2.01 kHz/%RH, which was about three orders of magnitude higher than that of the QCM sensor. In addition to the high sensitivity, the unique microstructure has also provided the CMUT humidity sensor with excellent all-around performance, including a short response/recovery time of 8 s/3 s, good reproducibility and linearity, and low hysteresis. The experimental results demonstrated the superiority of the CMUT sensor platform over the QCM counterpart. The major drawback of the CMUT sensor was the need for a DC bias voltage to pre-displace the resonant membrane. The bias voltage was 35 V in this work. It could be improved by optimizing the structural parameters of the device. For instance, by minimizing the cavity depth, reducing the bias voltage to 6-8 V is possible, which would be favorable for portable humidity sensing applications.


Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic lung disease characterized by dry cough, fatigue, and progressive exertional dyspnea. Lung parenchyma and architecture is destroyed, compliance is lost, and gas exchange is compromised in this debilitating condition that leads inexorably to respiratory failure and death within 3–5 years of diagnosis. This review discusses treatment approaches to IPF in current use and those that appear promising for future development.The data were obtained from the Randomized Controlled Trials and scientific studies published in English literature. We used search terms related to IPF, antifibrotic treatment, lung transplant, and management.Etiopathogenesis of IPF is not fully understood, and treatment options are limited. Pathological features of IPF include extracellular matrix remodeling, fibroblast activation and proliferation, immune dysregulation, cell senescence, and presence of aberrant basaloid cells. The mainstay therapies are the oral antifibrotic drugs pirfenidone and nintedanib, which can improve quality of life, attenuate symptoms, and slow disease progression. Unilateral or bilateral lung transplantation is the only treatment for IPF shown to increase life expectancy.Clearly, there is an unmet need for accelerated research into IPF mechanisms so that progress can be made in therapeutics toward the goals of increasing life expectancy, alleviating symptoms, and improving well‐being. The Gender, Age, and Physiology (GAP) Index Score encompasses both FVC and DLCO along with age and gender and is considered a practical index and staging system for predicting IPF mortality.Early diagnosis of IPF is difficult because initial symptoms, most commonly dyspnea and cough, are mild and nonspecific and overlap many other common conditions.The 6‐min walk test, an easy and straightforward way to determine exercise capacity by having the patient walk as far as possible in 6 min on a flat surface, has prognostic value since faster decline in distance covered is associated with higher mortality.The histopathological features of IPF are those of usual interstitial pneumonia (UIP) which appears under the microscope as a heterogeneous patchwork of focal areas of fibrosis with hyperplastic alveolar epithelial cells adjacent to these fibroblastic foci, alternating with less affected areas of normal or nearly normal lung tissue.IPF is most often imaged by computer tomography (CT), but a role for magnetic resonance imaging is emerging.In addition to the poor prognosis, IPF patients often have multiple comorbidities including hypertension, chronic obstructive pulmonary disease (COPD) emphysema, diabetes mellitus, and gastroesophageal reflux disease (GERD).3N‐acetylcysteine.Until 2014, the standard practice for treating IPF focused primarily on immunosuppressant therapy using a combination of prednisone, azathioprine, and Thalidomide is a drug with an infamous history, originally intended for use as a sedative and an anti‐emetic; it caused serious teratogenic effects and was subsequently removed from the market.In 2007, thalidomide was used on bleomycin‐induced pulmonary fibrosis in mice and in 2015 it was shown to protect against emphysematous changes in mice exposed to cigarette smoke.In 2012 at Johns Hopkins University School of Medicine, a 24‐week double blind randomized trial evaluated the antitussive action of thalidomide in IPF.In 2017, a cell culture study using rat lung epithelial cells (CCL‐149) showed that the presence of thalidomide mitigated TGF‐β1‐stimulated epithelial to mesenchymal transition.4Two antifibrotic therapies have been approved for the treatment of IPF: pirfenidone and nintedanib Table . PirfeniNintedanib is an intracellular tyrosine kinase inhibitor that binds to adenosine triphosphate binding sites, thus suppressing the signaling pathways linked to vascular endothelial growth factor receptor, fibroblast growth factor receptor 1–3, and platelet‐derived growth factor receptor α and β. These effects on receptor tyrosine kinases lead to decreased fibroblast activity.Either nintedanib or pirfenidone are good choices as the primary treatment for IPF at the present time.5Lung transplantation may be a viable treatment option for IPF.CO, oxygen desaturation, or decrease in distance covered during 6‐min walk test, pulmonary hypertension, or hospitalization due to respiratory decline, pneumothorax, or acute exacerbation.Determining the need for transplant is challenging, but in selecting IPF patients for transplant, risk of mortality and likelihood of survival after transplantation are key considerations. Furthermore, other comorbidities that may lead to complications such as cardiac dysfunction, GERD, diabetes, and obesity must be taken into account.Importantly, telomere shortening and mutations in genes that control telomere function such as Telomerase Reverse Transcriptase (TERT) and Telomerase RNA Component (TERC) are associated with familial and sporadic cases of IPF and this may be considered in transplant decision‐making.Before transplant, antifibrotic treatment is generally maintained and strict adherence to medication regimen is encouraged, even as clinical trials are being conducted to determine if this affects transplant outcome.Lung transplant may be either unilateral or bilateral. Benefits of unilateral transplant are the shorter wait times, easier procedure with lower perioperative complication rate, and the potential to improve the health of two patients from one donor.CO, and pulmonary hypertension.Follow‐up generally involves monitoring of FVC, DL66.1A nonpharmacological treatment being explored for used in IPF is based on the finding that mesenchymal stem cells (MSC), multipotent, undifferentiated cells, can regulate fibrotic processes and exert control over lung injury and repair.6.2The pentraxin protein family consists of three highly phylogenetically conserved acute phase reactant plasma proteins made in the liver which are known to be involved in inflammation and innate immunity.The first human clinical study on the pharmacokinetics and safety of PRM‐151, a recombinant human PTX2 protein, as a treatment for IPF, was a modest randomized, blinded, placebo‐controlled trial in 26 healthy volunteers between the ages of 18 and 53 years and 3 patients, 2 with familial interstitial pneumonia, and 1 with IPF, ages ranging between 29 and 72 years.CO was not affected by treatment, but 6‐min walking distance and FVC showed a trend toward an increase.In a randomized, double blind, placebo‐controlled, multiple ascending dose trial of PRM‐151 conducted in 3 centers, 21 patients between the ages of 40 and 80 years diagnosed with IPF were given PRM‐151 in 5 intravenous infusions over 15 days at doses of 1, 5, or 10 mg/kg or placebo. All doses were well‐tolerated and raised circulating levels of PTX2. DLIn a second randomized, double‐blind placebo‐controlled phase 2 study (PRM‐151‐202) conducted at 18 sites in 7 countries, 117 patients with IPF between the ages of 40 and 80 years received placebo or 10 mg/kg PRM‐151 every 4 weeks for 24 weeks after a three‐dose loading regimen, along with usual IPF treatment in 78%. Compared with placebo, the mean percentage of predicted FVC and 6‐min walking distance declined significantly less in the PRM‐151 group.An open label extension study to week 76 in which 74 patients continued treatment with PRM‐151 and 37 placebo‐treated patients crossed over to receive the drug showed persistent positive effect of treatment in those who continued and slowed rate of decline of FVC in those who crossed over. As expected in an IPF population, adverse events accumulated over time and most were not deemed to be related to treatment.6.3p = 0·013). Quantitative lung fibrosis scores obtained with high‐resolution computed tomography at 48 weeks showed significantly less fibrotic progression in the pamrevlumab group. The PRAISE findings are considered promising, but they are still limited by the small sample size. The ZEPHYRUS study , a phase 3 randomized, double‐blind, placebo‐controlled, multicenter clinical trial with plans to enroll 340 subjects, is ongoing and will evaluate efficacy and safety of pamrevlumab over 52 weeks.Pamrevlumab is a fully human recombinant monoclonal antibody that targets connective tissue growth factor (CTGF) and thus can possibly limit fibrotic progression.6.4Autotaxin (ATX) is an enzyme that hydrolyzes lysophosphatidyl choline into the signaling molecule lysophosphatidic acid (LPA).6.5ClinicalTrials.gov Identifier: NCT02257177).Galectin‐3 is a beta‐galactoside‐binding protein with pro‐fibrotic properties that is present at elevated levels in bronchoalveolar lavage fluid from patients with IPF.6.6Human antigen R (HuR), a member of the Hu/embryonic lethal, abnormal vision family of RNA binding proteins, is known to promote excessive inflammation and fibrogenesis in murine models of diabetic cardiovascular disease and liver disease.6.7The IPF Cell Atlas is a major initiative designed to make available single‐cell sequencing data on multiple cell types present in the lung with the ability to compare control and IPF cell transcriptomes.7Predicting the clinical course of IPF based on respiratory function and radiologic imaging is unreliable and, at this time, we cannot predict disease trajectory accurately.8clinicaltrials.gov identifier NCT04396756). Another approach to targeting TGFβ is via silencing RNA as exemplified by TRK‐250, a single‐stranded oligonucleotide that produces siRNA targeting human TGFβ mRNA. A phase 1 study of this inhaled nucleic acid medication is in progress with an estimated completion date of April 2022 .There is an urgent need for more attention and in‐depth research into development of targeted treatments that prolong life and improve quality of life for persons with IPF.Gene and protein expression profiling is beginning to generate information on the mechanisms that result in lung damage in IPF.All authors have no conflict of interest to declare.No ethics approval was needed, no human subjects were involved in this review paper, and no consent to participate and publish was needed.Conception: Reiss, Glass. Literature review: Renna, Grossfeld, Agarwala. Figures and manuscript writing: Reiss, Glass, Spiegler, De Leon. All authors provided critical review of the manuscript and approved this draft.


Sarcoidosis is a chronic granulomatous disease that can virtually affect any organ. Its etiology is unknown, although it has been proposed that environmental or biological agents can act as triggers, ultimately leading to chronic inflammation in genetically predisposed individuals. The main component of sarcoid inflammation is represented by an exaggerated T- lymphocytic cellular response to a putative antigen that could not be efficiently cleared in the patient. However, several clinical and immunological observations, such as the association of sarcoidosis to autoimmune diseases or the presence of autoantibodies in the serum of patients with sarcoidosis, suggest that humoral-mediated immune response might also play a role in the pathogenesis of sarcoidosis. The aim of this review is to deepen the relationship between sarcoidosis and autoimmunity, by analyzing the most recent advances and proposing new fields of research. Sarcoidosis is an inflammatory disease with variable clinical course, characterized by the presence of non-necrotizing granulomas in the involved organs; virtually, any organ can be affected, although the lung is one of the most frequently involved sites. The incidence of the disease varies widely depending on geographical area, showing the highest rates among Scandinavians and African Americans and the lowest ones in Asian countries; the average age of onset typically lies between 40 and 55 years of age. Etiology is unknown, even though it has been hypothesized that microorganisms, environmental factors, and inorganic materials could act as trigger(s) for inflammation in genetically predisposed individuals .The clinical course of sarcoidosis includes acute, chronic but stable, or chronic and progressive disease. In half of the cases, the disease resolves spontaneously within 2 years; in many other patients, remission occurs within 5 years, whereas a remission after 5 years is unlikely -DR3 molecules, expressed on dendritic cells or macrophages, and are recognized by a specific T cell receptor (TCR) β-chain variable segment 8 (TRBV8) and α-chain variable 2.3 (TRAV2.3) of a CD4-positive (TRAV2.3+TRBV22+CD4+) T cells. This particular mechanism activates an efficient immune response leading to antigen elimination and granuloma resolution. Conversely, if antigen presentation is not efficient because of the presence of other antigen-presenting cell HLA molecules or inefficient T-cell clones, a granuloma progression is established .An important contribution in maintaining a pro-inflammatory state at the level of granulomas is provided by sarcoid macrophages and epithelioid cells: they are able to express and release a significative amount of CCL20, the specific ligand of the CCR6 receptor of Th17 cells. Besides, CCL20 release is stimulated by pro-inflammatory cytokines, including IL-1β and TNF-α. The interaction between CCL20 and CCR6 leads to conspicuous pulmonary recruitment of Th17 cells. In this regard, Tøndell et al.  demonstrA local pro-inflammatory environment is also determined by the TL1A/DR3 axis activation in the lung of patients with sarcoidosis with active disease. The interaction between TNF-like ligand 1A (TL1A) and its death domain receptor 3 (DR3) shapes a signaling pathway that determines pro-inflammatory effects, namely memory CD4+ T-cell secretion of pro-inflammatory cytokines , Th17 cell differentiation and proliferation, and T-reg cell proliferation with an attenuated suppressive activity .The complexity of inflammatory response in sarcoidosis is attested also by the involvement of Th2- lymphocytes, which seems to occur specifically in the subset of patients with pulmonary fibrosis (PF). In fact, several evidence support the hypothesis that PF could be attributable to a switch from Th1 responses toward Th2, with a consequent release pattern of cytokines involved in PF, such as IL-13 and CCL2 . In particular, in the group of patients with sarcoidosis without concomitant AD, autoantibody profiling showed the presence of anti-mitochondrial antibody-M2, anti-Ro52, anti-Ro60, anti-SSB, anti-P0, anti-CCP, anti-β2-GP, antinuclear antibodies , anti-Sm antibody, and rheumatoid factor (RF). Interestingly, patients with sarcoidosis and autoantibodies showed higher levels of erythrocyte sedimentation rate (ESR), globulins, and CD4 cells in BALF, as well as a more advanced age compared to patients with sarcoidosis without autoantibodies. Moreover, age represented a risk factor for patients with sarcoidosis to develop autoantibodies even without the presence of AD .Although cell-mediated immunity is considered the main pathogenic factor for sarcoidosis, it is found that humoral immunity may also play a certain role. This is suggested, for example, from the evidence that patients with sarcoidosis are inclined to develop autoantibodies specific for several autoimmune diseases, regardless of the presence of clinical manifestations of the respective autoimmune disease (AD). In this regard, in a recent single-center retrospective study, performed on a sample of 154 patients with sarcoidosis and 100 sex and age-matched controls, Shi et al.  demonstrFukushima et al.  identifiIn the same way, Häggmark et al.  investigVimentin is a member of type III intermediate filaments involved in several cellular functions, such as cell motility and adhesion, subcellular organization, and maintenance of cell shape ; it has in vivo skin diagnostic test of sarcoidosis, known as the Kveim test. This reagent, injected intradermally in a patient with suspected sarcoidosis, determines a pathognomonic reaction after 4–6 weeks, with the presence of biopsy-proven sarcoid granulomas at the injection site  higher anti-vimentin IgG levels than controls and a greater prevalence of anti-vimentin IgG positivity . Then, they analyzed the effects of exposition to vimentin in pre-immunized mice to vimentin itself and in non-immunized controls mice: lung histopathology examination showed that granulomas in vimentin-immunized mice were significantly larger than those in controls (p < 0.0001). Interestingly, granuloma composition reflected the composition of sarcoid granuloma, including the presence of multinucleated giant cells, CD4 cells, and macrophages. Furthermore, flow cytometry analysis of BALF in vimentin-immunized mice showed higher numbers of CD45+ immune cells when compared to controls (p = 0.0082), most of which were represented by CD4 T cells. Finally, the analysis of vimentin-immunized mice lung RNA highlighted an upregulation, significantly higher than controls, of genes codifying for chemokines  and chemokine receptors , MHC II genes including H-2Eb1and immune-regulatory genes such as Pdcdlg2, Pdcd1, Foxp3, and Ctla4. Finally, the expression levels of Th1 and Th2 pathways genes  were significantly higher in vimentin-immunized mice than in the control mice.Another hint about a possible pathogenetic role of vimentin in sarcoidosis arises from a recent study that investigated the systemic immune response to vimentin and its capacity to induce granuloma formation in a murine model of pulmonary sarcoidosis . InitialThese findings also seem to suggest a probable specific pathogenetic role of vimentin in sarcoidosis disease. However, the presence of serum vimentin autoantibodies could not be considered pathognomonic of sarcoidosis disease, due to their presence in several autoimmune diseases, such as systemic erythematous lupus, antiphospholipid syndrome, and rheumatoid arthritis .A further tip about the possible role of autoimmunity in sarcoidosis is given from the frequent coexistence of sarcoidosis with autoimmune diseases.In this regard, Tana et al.  stated tRegarding thyroid disorders, Nakamura et al.  reportedIn the field of rheumatologic diseases, Judson et al.  identifiMoreover, a coexistence of sarcoidosis and hematologic autoimmune disorders has been described, with particular reference to autoimmune hemolytic anemia and primary immune thrombocytopenia , the latvs. 4% in controls, p = 0.00015) and gliadin antibodies in 12 patients .Finally, Papadopoulos et al.  demonstrRituximab is a B-cell depleting chimeric monoclonal antibody against human CD20 , initialRituximab could have a useful role also in the treatment of refractory sarcoidosis: Krause et al.  reportedThe effectiveness of rituximab in the treatment of sarcoidosis could be explained by its ability to modulate T-cellular response through interference with the role of B-lymphocytes acting as antigen-presenting cells to T-lymphocytes; on the other hand, another mechanism of action could be linked to the reduction of the levels of pathogenic or presumed pathogenic autoantibodies by indirectly reducing the amount of new plasma cells synthesis, for which B-cells are required . These pInteresting immunological parallelism can be drawn between COVID-19 and sarcoidosis.COVID-19 is an infectious disease caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that is responsible for the ongoing pandemic state outbreaking in December 2019 in Wuhan city, the capital of Hubei province in China.The clinical spectrum of SARS-CoV-2 infection is heterogeneous, ranging from asymptomatic infection to mild upper respiratory tract illness and severe viral pneumonia with respiratory failure and even death .Zhao et al.  identifiFirst of all, similarities between these diseases are suggested by clinical observations: several SARS-CoV-2-infected patients developed granulomatous manifestations and often a diagnosis of sarcoidosis was reached .Besides, a similarity is inherent to the likely pathogenic role of angiotensin-converting enzyme (ACE) in both diseases. ACE is a component of the renin-angiotensin system (RAS) axis that is involved in the homeostasis of cardiovascular function  and downFrom an immunological point of view, the authors highlighted that, similarly to patients with sarcoidosis, BALF cell count analysis of hospitalized patients with COVID-19 showed accumulation of CD4+ and CD8+ T cells and CD4/CD8 ratio often higher than 1.5; blood lymphocytopenia was also detected. These findings suggest local pulmonary recruitment of lymphocytes. Interestingly, BALF cell immunophenotyping revealed high levels of Th17.1 cells, suggesting a T-cellular response polarization similar to sarcoidosis, while histopathological analysis of lung specimens from deceased patients with COVID-19 showed an interstitial and perivascular lymphocyte infiltration .Moreover, an impaired function of Treg cells is also probably shared by both diseases, with a consequent role in amplifying immunoinflammatory response. COVID-19 and sarcoidosis share cytokine-releasing patterns: high levels of IL-6, IL-10, TNF-α, and IFN-γ are common in both diseases .Considering the role of humoral immune response in COVID-19 and sarcoidosis, an interesting consideration is offered by the analysis of the behavior of follicular helper T cells (Tfh), a class of CD4+ T cells involved in T-cell-mediated antibody responses and in communication to B cells . In patiMycobacterium tuberculosis, atypical mycobacteria, mycoplasma species and Propionibacterium acnes, several fungal and viral agents; inorganic agents  and organic agents like pine tree pollen, wheat, molds, and wood dusts , vWF, FTH1, or against several membranous and serum proteins .The main limit of these studies is linked to the essential need to demonstrate if autoantibodies detected in patients with sarcoidosis could have a significant role in the pathogenesis and in the influence of the disease course or not. In fact, the synthesis of supposed disease-specific autoantibodies in sarcoidosis could be alternatively explained in the context of the phenomenon of polyclonal hypergammaglobulinemia, classically intercepted in the sarcoidosis disease: Hunninghake et al.  demonstrThe concept of continuous B-cell stimulation in sarcoidosis is also supported by case reports attesting the development of multiple myeloma generally following a sarcoidosis diagnosis: Sen et al.  interestThe need to demonstrate a pathogenic role of autoantibodies in sarcoidosis stems from another observation, that is the possible presence of autoimmune disease-specific autoantibodies in patients with sarcoidosis in absence of the correspondent autoimmune disease itself. This particular clinical and immunological condition seems to frame the presence of autoantibodies in sarcoidosis as the result of a non-specific humoral activation.Another hypothesis that could explain autoantibodies synthesis in patients with sarcoidosis, in our opinion, is related to molecular mimicry, a phenomenon that occurs in the case of similarities between foreign and self-peptides, promoting activation of autoreactive T or B cells in a susceptible individual . MoleculIn parallel, the putative pathogenetic role of vimentin, a protein involved in several cellular functions, has also been investigated , 28, 29:In contrast with these considerations about a possible non-specific role of humoral immunity in the pathogenesis of sarcoidosis, the usefulness of rituximab in treating some refractory cases offers a strong suggestion about the weight that the B-cellular activity has in the disease: drug-induced B-cells depletion is illustrative of the importance that autoimmunity covers in this immunological context.In the light of these considerations, an interesting field of research could be related to the immunological phenotyping of patients with sarcoidosis. In other words, it could be useful to understand if patients with sarcoidosis show a different immunological setting when phenotypical features of the disease, such as organ involvement, illness duration, gender, or genetic arrangement, are considered. This could help to clarify why, notwithstanding the presence of autoimmune disease-specific autoantibodies, certain patients develop the related autoimmune disease while others do not. These observations could also have therapeutic implications: identifying factors that increase the propensity to develop humoral immunity alterations could help the physician in planning a more personalized follow-up and therapeutic strategies oriented to the control of the possible risk factors that could affect disease outcome.Another important suggestion arises from rituximab application in sarcoidosis: in fact, it could also be interesting to identify which autoantibodies are affected by B-cell drug-induced depletion, in order to better individuate which of them has a real pathogenetic significance.Concluding, sarcoidosis is a disease with complex immunological features, closely related to each other and influenced by environmental and genetic factors. In the pathogenesis of the disease, autoimmunity could have a certain role, as suggested by several immunological evidences, but further studies are necessarily required in order to identify immune biomarkers able to precisely assess the weight of autoimmune response in influencing disease outcome. In this regard, immunological phenotyping of patients with sarcoidosis could be useful, especially from the perspective of hoped precision medicine.LR reviewed the literature and drafted the manuscript. CS refined collected data and participated to study design. PS coordinated the study design, supervised data collection, discussed study results. All authors revised initial draft, and provided comments regarding important intellectual contribution, read, and approved the final review.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.