TCS Concentration Research Articles

Optimization of hydroxypropyl β-cyclodextrin-isophane insulin complex-loaded thiolated chitosan/sodium alginate nanoparticles using full factorial design

Isophane insulin (N) is challenging to administer orally due to its gastrointestinal instability. Research has shown that partially complexing N with hydroxypropyl β-cyclodextrin (HPβCD-N complexes) enhances its stability. Nanoparticles (NPs) are also frequently used to encapsulate drugs to protect them from degradation. This study aimed to optimize HPβCD-N complex-loaded thiolated chitosan/alginate (TCS/ALG) NPs using a full factorial design. The HPβCD-N complexes were prepared before being loaded into the NPs. Independent variables included the concentrations of TCS, ALG, and HPβCD-N complex, while the dependent variables were particle size and zeta potential. The results demonstrated that TCS and ALG concentrations had a positive and negative effect on particle size, respectively, with smaller particles being favored. The zeta potentials of the NPs increased positively and negatively in proportion to the TCS and ALG concentrations, respectively. The HPβCD-N complexes had a minimal effect on the dependent variables. The NPs made with TCS, ALG, and HPβCD-N complex concentrations of 0.075%, 0.0375%, and 5% w/w, respectively, were the most suitable for achieving small particle size and zeta potential within +30 mV and +50 mV. TEM images showed spherical particles with nanometer diameters. The encapsulated N was found to be approximately 1% w/w, confirming successful loading of N into the NPs. Thus, the optimized formulation shows potential as an NP carriers for N delivery.

Triclosan induces pyroptosis by activation of the caspase-9/3/gasdermin E axis

The high concentrations of TCS in personal care products, and the potential for even greater exposure in occupational settings, raise significant concerns about its cytotoxic effects. Numorous studies highlight the importance of understanding the molecular mechanisms of pyroptosis in toxicological research on environmental pollutants. However, it remains unclear whether TCS exposure could induce GSDME-mediated pyroptosis. In this study, we aimed to investigate the cytotoxic effects of 200 μM TCS on L02 cells and elucidate the molecular mechanisms involved in TCS-induced pyroptosis, a novel form of cell death. Our results demonstrate that TCS inhibits the proliferation of L02 cells in a dose-dependent manner and triggers caspase-dependent cell death, leading to mitochondrial dysfunction and subsequent pyroptosis through the activation of the caspase-9/3/GSDME axis. Furthermore, through transcriptional and metabolomic analyses, we identified alterations in the PI3K-Akt and MAPK cellular signaling pathways, as well as changes in carbon and nitrogen metabolism. Our data provide valuable insights into the biotoxicity of high TCS concentrations and establish a theoretical basis for future studies on its impact and risk.

Modeling and optimization of triclosan biodegradation by the newly isolated Bacillus sp. DL4: kinetics and pathway speculation.

Triclosan is a widely used antibacterial agent and disinfectant, and its overuse endangered ecological safety and human health. Therefore, reducing residual TCS concentrations in the environment is an urgent issue. Bacillus sp. DL4, an aerobic bacterium with TCS biodegradability, was isolated from pharmaceutical wastewater samples. Response surface methodology (RSM) and artificial neural network (ANN) were carried out to optimize and verify the different condition variables, and the optimal growth conditions of strain DL4 were obtained (35°C, initial pH 7.31, and 5% v/v). After 48h of cultivation under the optimal conditions, the removal efficiency of strain DL4 on TCS was 95.89 ± 0.68%, which was consistent with the predicted values from RSM and ANN models. In addition, higher R2 value and lower MSE and ADD values indicated that the ANN model had a stronger predictive capability than the RSM model. Whole genome sequencing results showed that many functional genes were annotated in metabolic pathways related to TCS degradation (e.g., amino acid metabolism, xenobiotics biodegradation and metabolism, carbohydrate metabolism). Main intermediate metabolites were identified during the biodegradation process by liquid chromatography-mass spectrometry (LC-MS), and a possible pathway was hypothesized based on the metabolites. Overall, this study provides a theoretical foundation for the characterization and mechanism of TCS biodegradation in the environment by Bacillus sp. DL4.

RETRACTED ARTICLE: Green synthesis of oncolytic Newcastle disease virus-loaded thiolated chitosan nanoformulation for CD44 targeted delivery and sustained release of virus in cervical cancer xenografts

BackgroundNewcastle disease virus (NDV) Lasota strain has proven oncolytic activity. One shortcoming associated with this treatment modality is the immune neutralization of the virus in body, mediated by natural killer cells and macrophages. This study aims at encapsulating the oncolytic virus in thiolated chitosan nanoparticles, surface functionalized with hyaluronic acid for CD44 targeted delivery and sustained release of NDV in cervical cancer tumors. These nanoparticles were tested for oncolytic potential in HeLa cells and cervical cancer xenograft model.ResultsNDV-loaded nanoparticles were prepared using TCs concentration of 1.0 mg/mL, HA at 0.5 mg/mL, with a half dose (not less than 500 TCID units) of NDV by using green synthesis approach through ionic gelation method. Viral quantification in nanoparticles was done by TCID50 (50% tissue culture infectious dose) and MOI (multiplicity of infection) determination. Ex vivo NK cell activity was analyzed by quantifying levels of IFN-γ. In vivo analysis was performed on wistar rats, immunocompromised by using ketoconazole (10 mg/kg) and cyclosporin (30 mg/kg) along with 0.1 μg/mL of amoxicillin. WBC profiling on day 7 confirmed immunosuppression, which was followed by tumor implantation. Zeta analysis of NDV nanoparticles showed that nanoparticles are 286.9 nm in size with a zeta potential of 18.1 mV and PDI of 0.241. For estimation of anticancer potential, MTT and trypan blue exclusion assay revealed a higher cytotoxic potential of the encapsulated virus, while TCID50 of HA-TC-NDV was 4.1 as compared to naked NDV virus which had TCID50 of 6.0 on HeLa cells. Histopathology of organs from NDV nanoparticle-treated rats showed syncytia formation in tumors, immunohistochemical analysis showed decrease in expression of TNF-α, COX-II and NF-ƙB which was also confirmed by ELISA. RT-PCR showed high viral copy number in tumor tissue and viral accumulation in lungs and liver. Lower IFN-γ in nanoparticles treated rats showed suppression in immunoreactivity of virus-loaded nanoparticles.ConclusionOur findings suggest that encapsulation of the virus in thiolated chitosan and CD44 targeting enhanced retention and sustained release of the virus in tumors as compared to pure NDV, with increased oncolytic effect both in vitro and in vivo.

Triclosan is associated with breast cancer via oxidative stress and relative telomere length.

Triclosan (TCS), a widely prescribed broad-spectrum antibacterial agent, is an endocrine-disrupting chemical. The relationship and biological mechanisms between TCS exposure and breast cancer (BC) are disputed. We aimed to examine the correlation between urinary TCS exposure and BC risk and estimated the mediating effects of oxidative stress and relative telomere length (RTL) in the above association. This case-control study included 302 BC patients and 302 healthy individuals in Wuhan, China. We detected urinary TCS, three common oxidative stress biomarkers [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α), 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)], and RTL in peripheral blood mononuclear cells. Significant associations were observed between log-transformed urinary concentrations of TCS, 8-OHdG, HNE-MA, 8-isoPGF2α, RTL, and BC risk, with the odds ratios (95% confidence intervals) being 1.58 (1.32-1.91), 3.08 (1.55-6.23), 3.39 (2.45-4.77), 3.99 (2.48-6.54), and 1.67 (1.35-2.09), respectively. Continuous TCS exposure was significantly positively correlated with RTL, HNE-MA, and 8-isoPGF2α (all p<0.05) but not with 8-OHdG (p = 0.060) after adjusting for covariates. The mediated proportions of 8-isoPGF22α and RTL in the relationship between TCS and BC risk were 12.84% and 8.95%, respectively (all p<0.001). In conclusion, our study provides epidemiological evidence to confirmed the deleterious effects of TCS on BC and indicated the mediating effect of oxidative stress and RTL on the correlation between TCS and BC risk. Moreover, exploring the contribution of TCS to BC can clarify the biological mechanisms of TCS exposure, provide new clues for the pathogenesis of BC, which is of great significance to improving public health systems.

Associations between seminal plasma triclosan and low sperm quality: A case-control study

ObjectiveTriclosan (TCS), a novel endocrine disrupter, has induced widespread human exposure due to its widespread use in personal care products. Environmental TCS exposure was suggested to be associated with human semen quality. However, little is known about seminal plasma TCS concentration and the risk of low sperm quality. This case-control study is established to examine the relationship between seminal plasma TCS and the risk of low sperm quality. Study designOne hundred men with low sperm quality as cases and one hundred normal men as controls were recruited a fertility clinic in Shijiazhuang, China, during 2018–2019. Seminal plasma TCS concentration was determined using an ultrahigh-performance liquid chromatography-tandem mass spectrometer (UPLC–MS/MS). Sperm concentration, sperm count, sperm motility and sperm progressive motility were evaluated according to World Health Organization (WHO) guidelines to assess the sperm quality. We used the Mann–Whitney rank–sum test and Kruskal–Wallis test to assess the differences of seminal plasma TCS concentration between the cases and the controls. In addition, logistic regression analysis was used to estimate the associations between seminal plasma TCS concentrations and low sperm quality risk adjusting for age, body mass index (BMI), abstinence time, smoking, and drinking Results and conclusionsThe level of seminal plasma TCS was observed slightly but not significantly higher in the case group than the control group. We also observed significant association between seminal plasma TCS concentrations and semen parameters in both control and case groups. Moreover, the seminal plasma TCS levels at the fourth quartile were found to be more likely to exhibit low sperm quality risk with increased adjusted odds ratios of 2.36 (95% confidence interval 1.03–5.39) compared to the first quartile. Our results reveal that seminal plasma TCS concentration was positively associated with low sperm quality risk.

Association between triclosan exposure and obesity measures among 7-year-old children in northern China

BackgroundTriclosan (TCS) is a widely used synthetic antibacterial compound with ubiquitous human exposure. Animal studies have suggested the obesogenic effect of TCS exposure, but knowledge regarding its impacts on childhood obesity was limited. ObjectiveTo investigate the associations of TCS exposure with childhood obesity in northern China. MethodsThis study included 423 children who participated in the 7-year-old follow-up visits of Laizhou Wan Birth Cohort in Shandong, northern China. Children’s TCS exposure were determined in spot urine samples via high performance liquid chromatography-tandem mass. Their height, weight, waist circumference, body fat percentage, body mass index (BMI), and waist-to-height ratio (WHtR) were measured or calculated. BMI z-score ≥ 85th percentile was defined as overweight/obesity, and WHtR ≥ 0.5 was considered to be abdominal obesity. Multivariable linear regressions, generalized linear models (GLMs), and multivariable logistic regressions were performed to examine the associations between TCS exposure and obesity measures in children. ResultsLinear regressions showed that TCS concentrations, when treated as continuous variables, were positively associated with BMI z-score (β = 0.12, 95% CI: 0.01, 0.24) and body fat percentage (β = 0.82, 95% CI: 0.13, 1.52). When TCS concentrations were categorized as a four-level ordinal variable, the results of GLMs were similar those of continuous variables and both of the positive trends were significant (p-trend = 0.049 for BMI z-score; p-trend = 0.023 for body fat percentage). Moreover, the higher TCS levels versus reference group were associated with an approximate 2–3 fold increased risk of abdominal obesity (p-trend = 0.044). ConclusionExposure to TCS was positively associated with obesity measures among 7-year-old children in northern, China. Given to the cross-sectional study design, a large prospective study is warranted to confirm our findings.

Antibiotics in elderly Chinese population and their relations with hypertension and pulse pressure.

Although antibiotic exposure in the general population has been well documented by a biomonitoring approach, epidemiologic data on the relationships between urinary antibiotic burden in the elderly with blood pressure (BP) are still lacking. The current study revealed thirty-four antibiotics in urine specimens from 990 elderly patients in Lu'an City, China, with detection frequencies ranging from 0.2 to 35.5%. Among the elderly, the prevalence of hypertension was 72.0%, and 12 antibiotics were detected in more than 10% of individuals with hypertension. The elderly with hypertension had the maximum daily exposure (5450.45 μg/kg/day) to fluoroquinolones (FQs). Multiple linear regression analyses revealed significant associations of BP and pulse pressure (PP) with exposure to specific antibiotics. The estimated β values (95% confidence interval) of associations with systolic blood pressure (SBP) in the right arm were 4.42 (1.15, 7.69) for FQs, 4.26 (0.52, 8.01) for the preferred as human antibiotics (PHAs), and 3.48 (0.20, 6.77) for the mixtures (FQs + tetracyclines [TCs] (tertile 3 vs. tertile 1)), respectively. Increased concentrations of TCs were associated with decreased diastolic BP (DBP; tertile 3: -1.75 [-3.39, -0.12]) for the right arm. Higher levels of FQs (tertile 3: 4.28 [1.02, 7.54]), PHAs (tertile 3: 4.25 [0.49, 8.01]), and FQs + TCs (tertile 3: 3.99 [0.71, 7.26]) were associated with increased SBP, and an increase in DBP for FQs (tertile 3: 1.82 [0.22, 3.42]) was shown in the left arm. Also, higher urinary concentrations of FQs (tertile 3: 3.18 [0.53, 5.82]), PHAs (tertile 3: 3.42 [0.40, 6.45]), and FQs + TCs (tertile 3: 3.06 [0.40, 5.72]) were related to increased PP, whereas a decline in PP for TCs (tertile 2: -2.93 [-5.60, -0.25]) in the right arm. And increased concentrations of penicillin V (tertile 3: 5.31 [1.53, 9.10]) and FQs + TCs (tertile 3: 2.84 [0.19, 5.49]) were related to higher PP in the left arm. By utilizing restricted cubic splines, our current study revealed a potential nonlinear dose-response association between FQ exposure and hypertension risk. In conclusion, this investigation is the first to present antibiotic exposure using a biomonitoring approach, and informs understanding of impacts of antibiotic residues, as emerging hazardous pollutants, on the hypertension risk in the elderly.

Environmental Exposure to Triclosan and Male Fecundity: A Prospective Study in China.

Triclosan (2,4,4′-trichloro-2′-hydroxy-diphenyl ether, TCS) is widely used in personal care and household products. It is ubiquitous across the ecosystem nowadays. Several in vitro and in vivo studies have suggested the possible adverse effects of TCS on male reproductive health. However, little research has been done on human beings, especially in eastern countries. To assess the effects of TCS exposure on male fecundity, we recruited couples who planned to conceive and went to the preconception care clinics for physical examination in Shanghai, China. TCS was quantified in male urine samples collected at enrollment. For this study, 443 couples were included in the cohort, and 74.7% of couples (n = 331) were prospectively followed 12 months later. The outcomes of interest included the pregnancy status of their wives and time to pregnancy. Elevated male urinary TCS concentrations were found to be associated with diminished fecundability (fecundability odds ratio (FOR) 0.77; 95% CI, 0.62–0.97). The risk of infertility significantly increased (OR = 1.6; 95% CI, 1–2.6) as TCS levels elevated. Besides, we divided TCS concentration into tertiles a priori, and there tended to be a dose-response pattern in both analyses. Our findings suggest that environmental exposure to TCS may have an adverse impact on male fecundity.

Review on Electrochemical Sensing of Triclosan using Nanostructured Semiconductor Materials

AbstractTriclosan (TCS) is an antifungal and antimicrobic component used in various cosmetic, healthcare, and personal care products; therefore, many people are exposed to this compound. Literature and related studies have shown inflammatory skin conditions and endocrine disruption after exposure to TCS. Low concentrations of TCS released into environmental wastewater and soil eventually increase the toxicity. Hence, the detection and sensing of TCS is an important process. Nanostructured semiconductor materials are widely used for the selective and sensitive sensing of TCS because of their high accuracy, wide linear range, and high conductivity. This Review describes the progress made in the use of nanostructured particles such as metal oxides and metal oxide nanocomposite, multiwalled carbon nanotubes (MWCNTs), carbon nanodots (CNDs), graphene, molecular imprinted polymers (MIPs), organic polymers, polymer nanocomposite, quantum dots (QDs), gold nanoparticles, silver nanoparticles, and other nanoparticles as electrode active materials for the electrochemical sensing of TCS in environmental samples.

Effect of Maternal Triclosan Exposure on Neonatal Thyroid-Stimulating Hormone Levels: A Cross-Sectional Study.

Objective This study is aimed at assessing the relationship between maternal urinary triclosan (uTCS) exposure and the thyroid-stimulating hormone (TSH) level of infant cord blood. Methods This cross-sectional study was carried out in 2019-2020 in Isfahan, Iran, and 99 pregnant women participated in the study. Urine samples were collected after the 28th week of pregnancy, and the concentration of TCS was measured using GC/MS. The cord blood levels of TSH (CBL-TSH) were measured. The association between uTCS and CBL-TSH was examined based on the general linear model. Results TCS was detected (≥0.01 ng/mL) in 100% of the urine samples, with the interquartile range (25%-75%) of uTCS levels 0.6-6.23 μg/g Cr. uTCS was not associated with CBL-TSH after adjustment for covariates. A significant relationship was observed between CBL-TSH of neonates born to mothers who had given birth only once compared to mothers who had given birth twice or more times. Conclusions Maternal exposure to TCS did not affect the infant CBL-TSH. However, the high concentrations of TCS in maternal urinary samples indicate the necessity of more precise regulations to decrease the use of this chemical in the industry and increase public awareness about using TCS-free compounds.

Interactions of microplastics and organic compounds in aquatic environments: A case study of augmented joint toxicity

High levels of persistent contaminants such as microplastics (MPs) and trace organic compounds (TrOCs) in the aquatic environment have become a major threat on the ecosystem and human health. While MP's role as a vector of environmental TrOCs is widely discussed in the literature, the corresponding implications of the interaction between these two compounds on human health (i.e., their joint toxic effect) have not been illustrated. Using a TrOCs model (Triclosan, TCS) and primary MPs (polystyrene microbeads), this work evaluates the sorption and desorption potential of TCS and MPs in simulated environmental and cellular conditions, respectively, and estimates the single and joint toxicity of these interactions toward human cells (Caco-2). Surface functionality of the microbeads highly increased their adsorption capacity of TCS, from 2.3 mg TCS for non−functionalized microbeads to 4.6 mg and 6.1 mg TCS per gram of microbeads for amino- and carboxyl-functionalized MPs, respectively. Using non-functionalized MPs, non-specific “hydrophobic-like” interactions and π-π interactions dominated the sorption mechanism of TCS; however, the addition of hydrogen interactions between functionalized microbeads and TCS increased the microbeads' overall sorption capacity. TCS was desorbed from both functionalized and non-functionalized MPs when changing from environmental conditions to cellular conditions. Desorption was found to be dependent on the matrix complexity and protein content as well as microbead functionality. Finally, toxicity tests suggested that while low concentrations of TCS and MPs (separately) have minor toxic effect toward Caco-2 cells, TCS-sorbed MPs at similar concentrations have an order of magnitude higher toxicity than pristine MPs, potentially associated with the close interaction of both MP and TCS with the cells. Overall, this study not only elucidates the role of MPs as a TrOC vector, but also demonstrates a realistic scenario in which co-presence of these environmental contaminants poses risks to the environment and human health.

Associations of Prenatal Exposure to Triclosan and Maternal Thyroid Hormone Levels: A Systematic Review and Meta-Analysis.

ObjectiveTo quantitatively evaluate associations between exposure to triclosan during pregnancy and maternal thyroid hormone levels.MethodThe databases of PubMed, Embase, Web of Science and Cochrane Library were systematically searched to identify relevant studies on the relationship between prenatal exposure to triclosan and maternal levels of serum thyroid hormone published before October 22, 2019. Stata 12.0 was used to examine the heterogeneity among the eligible studies.ResultsSeven studies involving a total of 4,136 participants were included. Overall, descriptive analysis provided no indication that exposure to TCS during pregnancy was related to either maternal FT4 levels (ES = 0.01, 95% CI: −0.03 to 0.05, P = 0.00) or TSH levels (ES = −0.03, 95% CI: −0.13 to 0.07, P = 0.412). Although the results were statistically insignificant, with the increase of urine TCS concentration, maternal FT4 levels exhibited a tendency to increase while TSH levels had a tendency to decrease during pregnancy.ConclusionThe results indicated that exposure to triclosan during pregnancy has no significant influence on maternal levels of thyroid hormone. On account of the inconsistency of existing research designs and study locations, further studies and replication are necessary to confirm these findings.

Biomarkers for the toxicity of sublethal concentrations of triclosan to the early life stages of carps

Accumulation, contents of protein, non-enzymatic antioxidant glutathione (GSH and GSSG), lipid peroxidation product (melondialdehyde-MDA) and organic acids (fumarate, succinate, malate and citrate), and activities of neurological (acetylcholinesterase-AChE), detoxification (glutathione S-transferase-GST) and metabolic (lactate dehydrogenase-LDH, aspartate transaminase-AST and alanine transaminase-ALT) enzymes were recorded in the hatchlings of Cyprinus carpio, Ctenopharyngodon idella, Labeo rohita and Cirrhinus mrigala after 7 and 14 days exposure and 10 days post exposure (recovery period) to sublethal concentrations (0.005, 0.01, 0.02 and 0.05 mg/L) of triclosan, a highly toxic and persistent biocide used in personal care products. Accumulation was maximum between 7–14 days at 0.01 mg/L for C. carpio and L. rohita but at 0.005 mg/L for C. idella and C. mrigala. No triclosan was observed at 0.005 mg/L in C. carpio and C. mrigala after recovery. Significant decline in protein, glutathione and acetylcholinesterase but increase in glutathione S-transferase, lactate dehydrogenase, aspartate transaminase, alanine transaminase, melondialdehyde and organic acids over control during exposure continued till the end of recovery period. Integrated biomarker response (IBR) analysis depicted higher star plot area for glutathione and glutathione S-transferase during initial 7 days of exposure, thereafter, during 7–14 days of exposure and the recovery period, higher star plot area was observed for acetylcholinesterase, aspartate transaminase, alanine transaminase and organic acids. Higher star plot area was observed for protein in all the species throughout the study. The study shows that L. rohita is most sensitive and glutathione, acetylcholinesterase, aspartate transaminase and alanine transaminase are the biomarkers for the toxicity of sublethal concentrations of TCS.

Effect of Pleurotus ostreatus and Trametes versicolor on triclosan biodegradation and activity of laccase and manganese peroxidase enzymes

IntroductionTriclosan (TCS) is an extensively used antibacterial agent which has been frequently detected in different environmental compartments. Because of TCS inhibition effect on vast majority of bacterial species, it is important to explore fungal species and their involved enzymes in TCS biodegradation. The aim of this study was to compare the potential of two white rot fungi Pleurotus ostreatus and Trametes versicolor for TCS biodegradation through the whole cell culture of fungi in an aqueous culture medium. Additionally, the changes in ligninolytic enzyme activities and possible correlations and contributions of degradative enzymes during TCS biodegradation process were monitored. Material and methodsThis study was carried out using a factorial experiment with a completely randomized design in three replications. factorial design in The experimental factors included: two white rot fungi Pleurotus ostreatus and Trametes versicolor and uninoculated controls which were subjected to five levels of TCS concentrations (0, 5, 10, 20, 30 and 50 μg mL−1) to assess ligninolytic enzymatic activity during biodegradation of TCS. Samples were harvested periodically at three time intervals (4, 7 and 10 days). An AB SCIEX 3200 QTRAP LC-MS/MS system was used in order to analyze the biodegradation of TCS in liquid medium. ResultsResults suggested that the two white rot fungi responded differently when exposed to the different concentrations of TCS. In general, P. ostreatus exhibited more potential and ligninolytic enzymatic activity compared to T. versicolor. LC-MS/MS analyses also showed that P. ostreatus degraded TCS with higher efficiency compared to T. versicolor. In addition, almost all P. ostreatus biodegradation activity was completed within the first day of sampling. Contrasting, less efficient degradation was observed by T. versicolor, reaching around 88% of TCS biodegradation at concentration of 20 μg mL−1after 10 days. At higher TCS concentrations (≥30 μg mL−1), the growth of T. versicolor severely inhibited and led to a drop in enzymatic activity and biodegradation. Furthermore, laccase and manganese peroxidase (MnP) were determined as more involved enzymes which significantly correlated to TCS biodegradation by T. versicolor and P. ostreatus, respectively. ConclusionP. ostreatus might be considered as efficient fungus in biodegradation of high amount of TCS in environmental matrices. The results of the present study might provide insights for future investigations on potential of fungi for applications in bioaugmentation-based strategies to remove TCS from wastewater and activated sludge.

Triclosan and triclocarbon in maternal-fetal serum, urine, and amniotic fluid samples and their implication for prenatal exposure

Triclosan (TCS) and Triclocarbon (TCC) are chlorinated synthetic antimicrobial agents formaternal urinelated in quantities of consumer products. However, the biomonitoring of direct exposure reflection for fetuses are rare. In this study, we determine the concentrations of TCS and TCC in paired maternal serum, cord serum, maternal urine, and amniotic fluid samples collected from a cohort of 95 expecting mother-fetal pairs in Southern China. TCS and TCC are detected widely (detection rates: >76.9%) in maternal serum, cord serum, maternal urine, and amniotic fluid samples. TCS is found to be the predominant antimicrobial agent with median concentrations in maternal serum (1.5 ng/mL) and cord serum (1.8 ng/mL) that are one order of magnitude higher than those of tcc in maternal serum (0.085 ng/mL) and cord serum (0.052 ng/mL), respectively. Cord serum concentrations of tcs and tcc correlated well with the concentrations in maternal serum, which reflect the mothers’ contribution to fetal exposure. The higher median ratio of cord serum/maternal serumTCS (0.95) compared to that of cord serum/maternal serumTCC (0.53) indicates high placental transmission ability of TCS. Moreover, the facility to penetrate the placental barrier and hard to depurate characteristics lead to the long residence of TCS in the fetal environment, causing great concern over the prenatal exposure risks during the critical window of fetal development. This study provides a novel contribution by increasing existing knowledge on the exposure assessment of TCS and TCC during pregnancy through the exploration of matched maternal-fetal samples.

Analyzing the inhibitory effect of metabolic uncoupler on bacterial initial attachment and biofilm development and the underlying mechanism

Metabolic uncouplers inhibit biofilm and biofouling formation in membrane bioreactor (MBR) systems, which have been considered as a potential biofouling control alternative. To better understand the inhibitory mechanism of uncoupler on biofouling, this study investigated the impact of the uncoupler 3, 3′, 4′, 5-tetrachlorosalicylanilide (TCS) on biofilm formation of B. subtilis in different development stages. Significant reductions in both the initial bacterial attachment stage and the subsequent biofilm development stage were caused by TCS at 100 μg/L. The motility of B. subtilis in semisolid medium was inhibited by TCS, which explicitly explained the reduction in initial bacterial attachment. Meanwhile, a reduction of extracellular polymeric substance (EPS) secretion owing to TCS suggested why biofilm development was suppressed. In addition, the fluorescent materials in tight-bound EPS (TB-EPS) and loose-bound EPS (LB-EPS) of Bacillus subtilis cultured in different TCS concentrations were distinguished and quantified by three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC). The results of this study suggested that the biofilm inhibitory mechanism of the uncoupler was both a inhibition in bacterial motor ability and a reduction in EPS secretion.

Ecological Toxicity of Triclosan (TCS): A Review

TCS has been detected in water systems and organisms all over the world. TCS in water body mostly exists at ng/L or g/L level. The highest content of TCS is mostly from sewage plant water samples, some of which reach 26.80 g/L. TCS concentration was 0.4-38.0 ng/g in maternal plasma and 0.022-0.95 ng/g in breast milk. TCS has been proved to be toxic to algae, plants, lower animals, amphibians, fish, mammals and other organisms at all levels, mainly in growth inhibition, lethal effect, endocrine interference, reproductive toxicity, DNA toxicity and so on.

Physical entrapment of chitosan in fixed-down-flow column bed enhances triclosan removal from water.

Triclosan (TCS) is an emergent pollutant with wide-ranging deleterious effects on aquatic organisms and humans. There is a growing concern about the development of low-cost and efficient treatment systems for the removal of TCS from water. This report describes the performance of a prototype of a continuous flow, fixed bed column device with physically entrapped industrial by-product chitosan. The effects of initial TCS concentration, adsorbent dose in the column matrix, and flow rate were investigated with regard to removal efficiency (%), adsorption capacity and breakthrough time. To understand the thermodynamic properties of the adsorption process, three kinetic models - Thomas, Yoon-Nelson and Adams-Bohart - were applied to the experimental data for the prediction of characteristic parameters of the adsorption process. The Yoon-Nelson model showed the best agreement between the experimental and calculated values. The column showed a near saturation state (Ct/C0 = 0.92; C0 and Ct are the concentration of TCS before and after treatment.) at 90 mg L-1 TCS concentration after 60 minutes. In view of non-availability of a treatment process for the emergent pollutant TCS, the data of the present investigation will facilitate the development of novel prototypes of column bed reactors for the removal of TCS.

Study of aquatic life criteria and ecological risk assessment for triclocarban (TCC)

Triclocarban (TCC) is used as a broad-spectrum antimicrobial agent, the intensive detection of TCC in aquatic environments and its potential risks to aquatic organisms are concerned worldwide. In this study, 8 Chinese resident aquatic organisms from 3 phyla and 8 families were used for the toxicity tests, and four methods were employed to derive the aquatic life criteria (ALC). A criterion maximum concentration (CMC) of 1.46 μg/L and a criterion continuous concentration (CCC) of 0.21 μg/L were derived according to the USEPA guidelines. The acute predicted no effect concentrations (PNECs) derived by species sensitivity distribution (SSD) methods based on log-normal, log-logistic and Burr Type Ⅲ models were 2.64, 1.88 and 3.09 μg/L, respectively. The comparisons of ALCs derived with resident and non-resident species showed that the CMC and CCC of TCC derived with Chinese resident species could provide a sufficient protection for non-resident species. The higher toxicity of TCC on aquatic organisms was found compared with other antimicrobial agents (except for Clotrimazole) in aquatic environment. The strong positive linear correlation was observed between the TCC and TCS concentrations in aquatic environment with a correlation coefficient (R2) of 0.8104, it is of great significance in environmental monitoring and risk assessment for TCC and TCS. Finally, the ecological risk assessment showed that the TCC in Yellow River basin and Pearl River basin had higher risk with the mean potential affected fractions (PAFs) of 9.27% and 7.09%, and 22.10% and 15.00% waters may pose potential risk for 5% aquatic organisms, respectively. In general, the risk of TCC in Asian waters was higher than that in Europe and North America.