Advances in understanding the reproductive toxicity of endocrine-disrupting chemicals in women.

Recently, there has been a noticeable increase in disorders of the female reproductive system, accompanied by a rise in adverse pregnancy outcomes. This trend is increasingly being linked to environmental pollution, particularly through the lens of Endocrine Disrupting Chemicals (EDCs). These external agents disrupt natural processes of hormones, including synthesis, metabolism, secretion, transport, binding, as well as elimination. These disruptions can significantly impair human reproductive functions. A wealth of animal studies and epidemiological research indicates that exposure to toxic environmental factors can interfere with the endocrine system's normal functioning, resulting in negative reproductive outcomes. However, the mechanisms of these adverse effects are largely unknown. This work reviews the reproductive toxicity of five major environmental EDCs-Bisphenol A (BPA), Phthalates (PAEs), Triclocarban Triclosan and Disinfection Byproducts (DBPs)-to lay a foundational theoretical basis for further toxicological study of EDCs. Additionally, it aims to spark advancements in the prevention and treatment of female reproductive toxicity caused by these chemicals.

Self-assembled copper nanoclusters used to mimic peroxidase for glucose detection.

A sensing system for glucose was established based on a self-assembled copper nanoclusters (Cu NCs)-based nano-enzyme and glucose oxidase (GOD). The assembled copper nanosheets (Cu NSs) were prepared in a one-step method using 2,3,4,5,6-pentafluorothiophenol (PFTP) as a reducing agent and protecting ligand. Cu NSs could be used to mimic the enzyme horseradish peroxidase. Cu NSs were endowed with excellent enzymatic catalytic activity in the oxidation of o-phenyldiamine (OPD) in the presence of H2O2. The latter could be generated in the aerobic oxidation of glucose catalyzed by GOD. Therefore, a detection method for glucose was constructed based on a Cu NSs-OPD-GOD catalytic system. This proposed sensing platform showed a standard linear range from 10 µM to 5 mM towards glucose, and the limit of detection was 5.5 µM. Finally, practical application of a sensor based on the Cu NSs nano-enzyme was verified in three sugared beverages as real samples. Our data reveal that the prepared Cu NSs could mimic peroxidase and be applied to a mixed catalytic system with GOD for glucose detection.

Glycosides and Their Corresponding Small Molecules Inhibit Aggregation and Alleviate Cytotoxicity of Aß40.

Polyphenols are the class of naturally synthesized compounds in the secondary metabolism of plants, which are widely distributed in fruits and vegetables. Their potential health treatment strategies have attracted wide attention in the scientific community. The abnormal aggregation of Aß to form mature fibrils is pathologically related to Alzheimer's disease (AD). Therefore, inhibiting Aß40 fibrillogenesis was considered to be the major method for the intervention and therapy of AD. Glycosides, as a cluster of natural phenolic compounds, are widely distributed in Chinese herbs, fruits, and vegetables. The inhibitory effect of glycosides (phloridzin, salidroside, polydatin, geniposide, and gastrodin) and their corresponding small molecules (phloretin, 4-hydroxyphenyl ethanol, resveratrol, genipin, and 4-hydroxybenzyl alcohol) on Aß40 aggregation and fibrils prolongation, disaggregation against mature fibrils, and the resulting cytotoxicity were studied by systematical biochemical, cell biology and molecular docking techniques, respectively. As a result, all inhibitors were observed against Aß40 aggregation and fibrils prolongation and disaggregated mature Aß40 fibrils in a dose-dependent manner. Besides, the cell validity experiments also showed that all inhibitors could effectively alleviate the cytotoxicity induced by Aß40 aggregates, and the glycoside groups played important roles in this inhibiting process. Finally, molecular docking was performed to study the interactions between these inhibitors and Aß40. Docking showed that all inhibitors were bound to the similar region of Aß40, and glycoside group formed hydrogen bonds with the pivotal residues Lys16. These results indicated that the glycoside groups could increase the inhibitory effects and reduce cytotoxicity. Glycosides have tremendous potential to be developed as an innovative type of aggregation inhibitor to control and treat neurodegenerative diseases.

Enzyme mimics based membrane reactor for di(2-ethylhexyl) phthalate degradation.

Di(2-ethylhexyl) phthalate (DEHP), the most abundantly used plasticizer, was considered to be a hazardous chemical that was difficult to be degraded naturally. In this study, inspired by the "catalytic triad'' in serine proteases, an enzyme mimic material was developed by combining the proteases's active sites of serine, histidine and aspartate (S-H-D) with the self-assembling sequence of LKLKLKL and the aromatic group of fluorenylmethyloxycarbonyl (Fmoc). By mixing the monomer of peptides containing separate S, H and D residues with a ratio of 2:1:1, the enzyme mimics were found to co- assemble into nanofibers (Co-HSD) and showed the highest activity towards DEHP degradation because of the synergistic effects of active sites, orderly secondary structure and stable molecular conformation. To further improve ability and applicability, the high active mimetic enzyme was immobilized onto regenerated cellulose (RC) membranes for DEHP degradation in a continuous recycling mode. The RC membranes were first functionalized by the NaIO4 oxidation method to form aldehyde groups and then conjugated with the enzyme mimics via Schiff-base reaction. As a biocatalytic membrane, this membrane could not only effectively degrade DEHP, but also showed good stability, thus establishing a promising biomaterial for large scale biodegradation of DEHP in water decontamination and liquid food depollution.

Enzyme mimics based on self-assembled peptides for di(2-ethylhexyl)phthalate degradation.

Enzyme mimics have been developed by imitating and incorporating specific features of native enzymes to achieve catalytic activity, and are expectedly comparable to that of native enzymes. Here, inspired by the "catalytic triad" in serine proteases, a series of peptide-based enzyme mimics were designed to follow the rational design principle of peptides via self-assembly, and were further applied in the degradation of di(2-ethylhexyl)phthalate (DEHP). The relationship of the structure of enzyme mimics with their degradation activity was analyzed by transmission electron microscopy, fluorescence spectroscopy, circular dichroism, Raman spectroscopy, X-ray diffraction spectroscopy, and computational modeling. These results show that the hydrophobic skeleton, amino acid sequence, species, and periodic distribution have important effects on the structure of the peptide sequence and the number of hydrogen bonds; in addition, pH can also affect the self-assembly characteristics of peptides and the formation of stable fibers, which are all closely linked to the catalytic activity of the enzyme mimics. The self-assembled peptides had a stable fibrous morphology and secondary structure after the DEHP degradation assay. The enzyme mimics with high catalytic activity constructed from the self-assembled peptides may provide guidance for the future degradation of DEHP in food packaging or water treatment, and also give insights into the design of enzyme mimics in other related fields.

The stabilization of fluorescent copper nanoclusters by dialdehyde cellulose and their use in mercury ion sensing.

In the synthesis of metal nanoclusters (NCs), small molecules are widely used as capping ligands and reducing agents. However, metal NCs are usually sensitive to solvents and aerobic atmosphere and are also prone to oxidation; thus, their photonic properties deteriorate. In this work, 4-aminothiophenol (PATP) was used as a ligand to prepare Cu NCs and their fluorescence, morphology, and electronic states were characterized. The as-prepared Cu NCs could be dispersed in aqueous media and their fluorescence was sensitive to Hg2+. It was found that after mixing Cu NCs with 2,3-dialdehyde cellulose (DAC) prepared via oxidation by NaIO4, the fluorescence stability of Cu NCs could be enhanced from overnight to 7 days. This might be due to the reaction of the amine group of PATP with the aldehyde group of DAC to form Schiff bases, which are then reduced to form more stable C-N bonds via reduction by NaBH4. Therefore, Cu NCs were attached to a rigid skeleton and their stability increased. Furthermore, the composite of Cu NCs mixed with DAC could be used to prepare colorimetric cards for the rapid detection of Hg2+ with high sensitivity.

Fluorescent methylammonium lead halide perovskite quantum dots as a sensing material for the detection of polar organochlorine pesticide residues.

Methylammonium lead halide perovskite quantum dots (MAPB-QDs) have been widely used for photovoltaic devices due to their special electronic structures. In this work, MAPB-QDs were used for the first time to detect polar organochlorine pesticides (OCPs) based on the phenomenon that the fluorescence spectra of MAPB-QDs were blue-shifted in the presence of polar OCPs. Furthermore, 1H NMR, FTIR, XPS and XRD were performed first to illustrate the sensing mechanism. In the presence of polar OCPs, the MAPB-QDs' capping ligands, oleic acid (OA) and oleylamine (OAm), were replaced with OCPs and then the chlorine element was adequately doped into QDs, resulting in the increase of the MAPB-QDs' bandgap. As result of the insufficient stability of MAPB-QDs in the presence of moisture, MAPB-QDs were mixed with PDMS and used as the colorimetric cards for fast detection of OCPs in real samples.

Hydroxycinnamic Acid from Corncob and Its Structural Analogues Inhibit Aß40 Fibrillation and Attenuate Aß40-Induced Cytotoxicity.

The aggregation of amyloid-ß protein (Aß) is deemed a vital pathological feature of Alzheimer's disease (AD). Hence, inhibiting Aß aggregation is noticed as a major tactic for the prevention and therapy of AD. Hydroxycinnamic acid, as a natural phenolic compound, is widely present in plant foods and has several biological activities including anti-inflammation, antioxidation, and neuroprotective effects. Here, it was found that hydroxycinnamic acid and its structural analogues (3-hydroxycinnamic acid, 2-hydroxycinnamic acid, cinnamic acid, 3,4-dihydroxycinnamic acid, 2,4-dihydroxycinnamic acid, and 3,4,5-trihydroxycinnamic acid) could inhibit Aß40 fibrillogenesis and reduce Aß40-induced cytotoxicity in a dose-dependent manner. Among these small molecules investigated, 3,4,5-trihydroxycinnamic acid is considered to be the most effective inhibitor, which reduces the ThT fluorescence intensity to 30.79% and increases cell viability from 49.47 to 84.78% at 200 µM. Also, the results with Caenorhabditis elegans verified that these small molecules can ameliorate AD-like symptoms of worm paralysis. Moreover, molecular docking studies showed that these small molecules interact with the Aß40 mainly via hydrogen bonding. These results suggest that hydroxycinnamic acid and its structural analogues could inhibit Aß40 fibrillogenesis and the inhibition activity is enhanced with the increase of phenolic hydroxyl groups of inhibitors. These small molecules have huge potential to be developed into novel aggregation inhibitors in neurodegenerative disorders.

Perspective on recent developments of nanomaterial based fluorescent sensors: Applications in safety and quality control of food and beverages.

As the highly toxic pollutants will seriously harm human health, it is particularly important to establish the analysis and detection technology of food pollutants. Compared with the traditional detection methods, fluorescent detection techniques based on nanomaterials trigger wide interesting because of reduced detection time, simple operation, high sensitivity and selectivity, and economic. In this review, the application of fluorescent sensors in food pollutants detection is presented. Firstly, conventional fluorescent nanomaterials including metal-based quantum dots, carbon dots, graphene quantum dots and metal nanoclusters were summarized, with emphasis on the photoluminescence mechanism. Then, the fluorescence sensors based on these nanomaterials for food pollutants detection were discussed, involving in the established methods, sensor mechanisms, sensitivity, selectivity, and practicability of fluorescence sensors. The selected analytes focus on five types of higher toxic food pollutants, including mycotoxins, foodborne pathogens, pesticide residues, antibiotic residues, and heavy metal ions. Finally, outlook on the future and potential development of fluorescence detection technology in the field of food science were proposed, including green synthesis and reusability of fluorescence probes, large-scale industrialization of sensors, nondestructive testing of samples and degradation of harmful substances.

CLVFFA-Functionalized Gold Nanoclusters Inhibit Aß40 Fibrillation, Fibrils' Prolongation, and Mature Fibrils' Disaggregation.

The abnormal aggregation of amyloid beta (Aß or A beta) from monomeric proteins into amyloid fibrils is an important pathological contact to Alzheimer's disease (AD). Amyloid beta 40 (Aß40), the pivotal biomarker of AD, aggregates to form amyloid plaques. For this reason, inhibition of amyloid fibrillation had become a crucial prevention and therapeutic strategy. Usually, LVFFA is the central hydrophobic fragment of Aß and can inhibit the aggregation of Aß40. In this work, in order to improve the inhibitory ability of LVFFA, hexapeptide CLVFFA were conjugated at the surface of Au clusters (AuNCs) to manufacture a nanosized inhibitor, AuNCs-CLVFFA. Thioflavin T fluorescence and transmission electron microscope results showed that AuNCs-CLVFFA inhibited Aß40 fibrillogenesis, fibrils' prolongation, and mature fibrils' disaggregation. Furthermore, AuNCs as the backbone of the inhibitor showed extraordinary inhibition ability for Aß40 aggregation at a low AuNCs-CLVFFA concentration. Free hexapeptide CLVFFA, at the same concentration, showed almost no inhibition. Additionally, the inhibitor could maintain the optical properties of nanoclusters, and the cell viability demonstrated that the inhibitor had good biocompatibility and may potentially be applied into AD therapy or treatment.

AuNP-peptide probe for caspase-3 detection in living cells by SERS.

Colloidal nanoparticles can be used as surface-enhanced Raman scattering (SERS) substrates because the very close spacing between particles existing in these colloidal systems is beneficial for the generation of extremely strong and highly spatially localized electric field enhancements. Herein, a caspase-3-specified peptide was used as a molecular cross-linker to engineer gold nanoparticle (AuNP) junctions in a controllable manner. The peptide was designed with a sequence of CCALNNPFFDVED (Cys-Cys-Ala-Leu-Asn-Asn-Pro-Phe-Phe-Asp-Val-Glu-Asp) or CCALNNKYDDVED (Cys-Cys-Ala-Leu-Asn-Asn-Lys-Tyr-Asp-Asp-Val-Glu-Asp), where the CALNN (Cys-Ala-Leu-Asn-Asn) fragment helps to stabilize AuNP suspension in aqueous media and the sequence of DVED (Asp-Glu-Val-Asp) can be cleaved by caspase-3. In addition, the PFF (Pro-Phe-Phe) or KYD (Lys-Tyr-Asp) was exposed and interacted via the hydrophobic or alternate negative and positive electro-interaction in the presence of caspase-3, inducing the aggregation of colloidal Au-peptides accompanied with the enhancement of SERS. It can be observed that the SERS-enhanced signals were correlated with the caspase-3 concentrations and the limit of detection can reach 1.5 ng mL-1. Finally, this caspase-3-specified AuNP-peptide probe has been found to be a promising candidate for its application in the analysis of caspase-3 in living cells.

Highly Bright Self-Assembled Copper Nanoclusters: A Novel Photoluminescent Probe for Sensitive Detection of Histamine.

In this work, highly photoluminescent (PL) self-assembled copper nanoclusters (Cu NCs) capable of rapid, sensitive, and selective detection of histamine were developed. Cu NCs were synthesized in facile conditions by using 2,3,5,6-tetrafluorothiophenol (TFTP) as both the reducing agent and the protecting ligand, which exhibited intense saffron yellow (590 nm) PL via self-assembled induced emission (SAIE), and the absolute quantum yield (QY) of assembly was as high as 43.0%. The size, electronic states, and morphologies of the assembled nanoribbons were characterized, and the geometric structure and spectral properties of the Cu NCs were investigated by theoretical study. Furthermore, the mechanism of the excellent sensing performance of Cu NCs toward histamine was demonstrated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). With this sensing system, the amount of histamine in fish, shrimp, and red wine were analyzed, and experiment results verified the application of the sensor. Importantly, the luminescent test strips based on Cu NCs were fabricated for colorimetric detection of histamine in foods. This proposed technique may provide an alternative to traditional methods for histamine detection.

Metal composition of ambient PM2.5 influences the pulmonary function of schoolchildren: A case study of school located nearby of an electric arc furnace factory.

The present study combined air sampling with pulmonary function tests (PFTs) to determine both the extent of air pollution proximal to an electric arc furnace (EAF) and its impact on human health. The mass concentrations of particulate matter with aerodynamic diameters less than 2.5 µm (PM2.5) in exposure areas were not significantly higher than the samples taken at a control area. However, the concentrations of five metal elements, Cd, Cr, Cu, Ni, and Zn in PM2.5 were significantly higher in the exposure area than that of the control area. PFTs showed that the average forced vital capacity (FVC) of boys was decreased with decreasing distance from the EAF factory. With normalization of pulmonary function by age, height, and weight, we found that the FVC became more negative with a decrease in distance from the EAF. Lastly, regression analysis was performed to analyze the impact of the concentrations of the five metals in PM2.5 on the performance of pulmonary function. The results showed that the metals can be ranked from the highest to the lowest in terms of impact on the FVC of boys as follows: Cr, Cd, Ni, Cu, and Zn. This finding is consistent with the ranking of metal toxicity reported in the literature for a rat lung epithelial cell line. The results of this study showed that only measuring PM2.5 mass concentrations may not provide a full explanation of its toxicity and health effects. The chemical composition of the PM2.5 can be an important factor that determined the health impact of PM2.5.

Synthesis of highly fluorescent gold nanoclusters and their use in sensitive analysis of metal ions.

As a promising fluorescent material, gold nanoclusters (Au NCs) have been used for biosensing and imaging. In metal ion sensing, the fluorescence of Au NCs is usually quenched in the presence of ions, but the reaction mechanism has not been clarified. In this work, mercaptan acids (3-mercaptopropanoic acid (3-MPA), 6-mercaptohexanoic acid (6-MHA), 11-mercaptoundecanoic acid (11-MUA) and 16-mercaptohexadecanoic acid (16-MHA)) were used as reductants and ligands to synthesize fluorescent Au NCs. The Au NCs had a core containing 18 atoms capped by 18 (3-MPA) or 10 (6-MHA, 11-MUA, 16-MHA) ligand molecules. The Au NCs prepared in this work had higher fluorescence quantum yields than those reported previously and the fluorescence showed a red-shift when varying the chain length of the mercaptan acids. It was found that in presence of ions (Mo(vi), Hg(ii)), the fluorescence of the Au NCs is dependent upon the ligands. The Au NCs with 3-MPA and 6-MHA ligands were sensitive to Mo(vi) and Hg(ii), while the Au NCs capped with 11-MUA and 16-MHA ligands were not sensitive to the ions. Various characterization techniques, including transmission electron microscopy, matrix-assisted laser-desorption ionization time of flight mass spectrometry, X-ray photoelectron spectroscopy, UV-Vis absorption spectroscopy and thermogravimetric analysis, were used to investigate the components and electronic structure of the clusters, as well as the emission and excitation properties before and after the reaction with metal ions. The structure of the Au NCs after the reaction with Mo(vi) and Hg(ii) was also studied. It was found that Mo(vi) and Hg(ii) both reacted with the gold atoms at the core site, but the reaction mechanisms were different.

Rapid detection of six phosphodiesterase type 5 enzyme inhibitors in healthcare products using thin-layer chromatography and surface enhanced Raman spectroscopy combined with BP neural network.

A novel facile method for the detection of the phosphodiesterase type 5 enzyme inhibitors added illegally into health products was established using thin-layer chromatography and surface enhanced Raman spectroscopy combined with BP neural network. When the detection conditions were optimized in detail, a repetitive adding procedure of silver colloids with the total amount keeping constant was used to improve the enhancement effect of surface enhanced Raman spectroscopy. According to the main Raman peaks and the retention factor of analyte, the data predictive model was established. Under the optimized experimental conditions, this method was successful to apply to detect the artificially produced model samples, and the limit of detection less than 5 mg/kg was obtained. Based on the excellent sensitivity of this method, the real samples have been detected accurately and the detection results were confirmed by high-performance liquid chromatography. In addition, the developed method was suitable for the detection of other adulterants, especially those that have similar chromatographic or spectroscopic behaviors.

Artificial hydrolase based on carbon nanotubes conjugated with peptides.

An artificial enzyme was constructed by attaching short peptides with active sites (SHELKLKLKL, WLKLKLKL) onto carbon nanotubes (CNT). It was found that the combination of SHE amino acids was essential to form a catalytic triad. W was also incorporated into this artificial enzyme and acted as a substrate binding site, thus producing an enzyme model with synergism of 67.7% catalytic groups and 32.3% binding groups, CNT-(SHE/W)2:1-LKLKLKL. When the peptide SHELKLKLKL was attached with the catalytic triad site close to the surface of CNT, the composite had higher activity than a leucine-attached system terminated with the catalytic triad site, suggesting that CNT not only served as a platform for attaching active amino acids, but also created a hydrophobic microenvironment and facilitated the proton transfer process to enhance the catalytic activity. The artificial enzyme exhibited Michaelis-Menten behaviour, indicating that it was indeed a mimic of the corresponding natural enzyme. This work showed that a well-designed combination of CNT and short peptides containing active sites can mimic a natural enzyme.