In situ amplified photothermal immunoassay for neuron-specific enolase with enhanced sensitivity using Prussian blue nanoparticle-loaded liposomes.

Methods based on prussian blue nanoparticles (PBNPs) have been reported for photothermal immunoassays in analytical nanoscience fields but most suffer from low sensitivity and are not beneficial for routine use. Herein, we design an in situ amplified near-infrared (NIR) photothermal immunoassay for the quantitative screening of neuron-specific enolase (NSE) on a portable thermometer using PBNP-encapsulated nanoliposomes as photosensitive materials. Biotinylated liposomes loaded with numerous prussian blue nanoparticles were synthesized through a typical reverse-phase evaporation method. The photothermal immunoassay was carried out in an anti-NSE capture antibody-coated microplate using the biotinylated anti-NSE secondary antibody. With the sandwiched immunoreaction and the biotin-avidin linkage, the subsequent photothermal measurement of PBNPs released from the liposomes with buffered surfactant including Tween 20 was conducted on a digital thermometer under near-infrared 808 nm laser irradiation, accompanied by the convertion of NIR-light wavelength to heat. Under the optimum conditions, the photothermal immunoassay displayed a wide dynamic concentration range of 0.1-100 ng mL-1 with a low detection limit for NSE of 0.053 ng mL-1. Good reproducibility (RSD ≤ 2.78% for intra-assay; RSD ≤ 4.39% for inter-assay), high selectivity against other biomarkers, and a long-term stability (≥94.9% of the initial signal during six-month storage) were acquired in the photothermal immunoassay. Impressively, the analysis of 7 human serum specimens for target NES via the photothermal immunoassay also gave well-matched results with the referenced human NSE enzyme-linked immunosorbent assay.

Cross-linkage urease nanoparticles: a high-efficiency signal-generation tag for portable pH meter-based electrochemical immunoassay of lipocalin-2 protein diagnostics.

An innovative signal-transduction tag based on cross-linked urease nanoparticles (CLENP) was designed for the development of a pH meter-based immunoassay of lipocalin-2 (LCN2). The CLENP was synthesized with a typical desolvation method using ethanol as desolvation agent, followed by functionalization with polyaspartic acid. The carboxylated CLENP were used as the signal-generation tags for the labelling of secondary antibodies via the carbodiimide coupling. Upon target LCN2 introduction, a sandwich-type immune reaction was performed between capture antibody-coated plate and the labeled secondary antibody on the CLENP. The conjugated CLENP in the microplate hydrolyzed urea into ammonia (NH4+) and carbonate (CO32-), resulting in the pH change of solution, which was determined with a handheld pH meter. The pH variation was proportional to target concentration in the sample. By monitoring the pH variation of the urea solution, the level of LCN2 at a concentration as low as 5.2 pg mL-1 was evaluated. The pH meter-based electrochemical immunoassay can be utilized for mass production of miniaturized lab-on-a-chip devices with handheld pH meter, thereby opening new opportunities for protein diagnostics and biosecurity. Graphical abstract An innovative signal-transduction tag based on cross-linked urease nanoparticles was designed for high-efficiency immunoassay of lipocalin-2 with pH meter readout.

A potentiometric immunosensor for enterovirus 71 based on bis-MPA-COOH dendrimer-doped AgCl nanospheres with a silver ion-selective electrode.

Herein a new potentiometric immunoassay for the point-of-care detection of enterovirus 71 (EV71) was developed by using a silver (Ag+) ion-selective electrode (ISE). Initially, the carboxylated dendrimer-doped AgCl nanospheres were synthesized by the reverse micelle method. Then the synthesized nanospheres were used to label a polyclonal mouse anti-EV71 antibody via a typical carbodiimide coupling method. The immunoreaction was executed on a monoclonal anti-EV71 antibody-coated microplate by using biofunctional AgCl nanospheres as the detection antibody. With a sandwich-type immunoassay format, the carried AgCl nanospheres could be dissolved in the presence of NH3·H2O, and the released silver ions were determined with an external silver ion-selective electrode. Under optimal conditions, the shift in the potential increased with the increase in the EV71 concentration, in a wide linear range of 0.3-300 ng mL-1, with a detection limit of 0.058 ng mL-1. Intra- and inter-assay relative standard deviations with identical batches were less than 4.15% and 6.15%, respectively. By validating the spiked serum samples, our system shows consistency with the enzyme-linked immunosorbent assay (ELISA) kit.

Silver-functionalized g-C3N4 nanohybrids as signal-transduction tags for electrochemical immunoassay of human carbohydrate antigen 19-9.

A simple and feasible electrochemical immunosensing platform was developed for highly efficient screening of a disease-related protein (human carbohydrate antigen 19-9, CA 19-9 used in this case) using silver-functionalized g-C3N4 nanosheets (Ag/g-C3N4) as signal-transduction tags. Initially, Ag/g-C3N4 nanohybrids were synthesized by combining thermal polymerization of the melamine precursor with the photo-assisted reduction method. Thereafter, the as-synthesized Ag/g-C3N4 nanohybrids were utilized for the labeling of the anti-CA 19-9 detection antibody by using a typical carbodiimide coupling method. The assay was carried out on a capture antibody-modified glassy carbon electrode in a sandwich-type detection mode. The detectable signal mainly derived from the voltammetric characteristics of the immobilized nanosilver particles on the g-C3N4 nanosheets within the applied potentials. Under the optimal conditions, the voltammetric peak currents increased with the increasing amount of target CA 19-9, and exhibited a wide linear range from 5.0 mU mL(-1) to 50 U mL(-1) with a detection limit of 1.2 mU mL(-1). Our strategy also displayed good reproducibility, precision and specificity. The results of the analysis of clinical serum specimens were in good accordance with the results obtained by an enzyme-linked immunosorbent assay (ELISA) method. The newly developed immunosensing system is promising for enzyme-free and cost-effective analysis of low-abundance proteins.

Molecular identification and functional analysis of a maize (Zea mays) DUR3 homolog that transports urea with high affinity.

MAIN CONCLUSION: Successful molecular cloning and functional characterization of a high-affinity urea permease ZmDUR3 provide convincing evidence of ZmDUR3 roles in root urea acquisition and internal urea-N-remobilization of maize plants. Urea occurs ubiquitously in both soils and plants. Being a major form of nitrogen fertilizer, large applications of urea assist cereals in approaching their genetic yield potential, but due to the low nitrogen-use efficiency of crops, this practice poses a severe threat to the environment through their hypertrophication. To date, except for paddy rice, little is known about the biological basis for urea movement in dryland crops. Here, we report the molecular and physiological characterization of a maize urea transporter, ZmDUR3. We show using gene prediction, PCR-based cloning and yeast complementation, that a functional full-length cDNA encoding a 731 amino acids-containing protein with putative 15 transmembrane α-helixes for ZmDUR3 was successfully cloned. Root-influx studies using (15)N-urea demonstrated ZmDUR3 catalyzes urea transport with a K m at ~9 µM when expressed in the Arabidopsis dur3-mutant. qPCR analysis revealed that ZmDUR3 mRNA in roots was significantly upregulated by nitrogen depletion and repressed by reprovision of nitrogen after nitrogen starvation, indicating that ZmDUR3 is a nitrogen-responsive gene and relevant to plant nitrogen nutrition. Moreover, detection of higher urea levels in senescent leaves and obvious occurrence of ZmDUR3 transcripts in phloem-cells of mature/aged leaves strongly implies a role for ZmDUR3 in urea vascular loading. Significantly, expression of ZmDUR3 complemented atdur3-mutant of Arabidopsis, improving plant growth on low urea and increasing urea acquisition. As it also targets to the plasma membrane, our data suggest that ZmDUR3 functions as an active urea permease playing physiological roles in effective urea uptake and nitrogen remobilization in maize.

Sensitive electrochemical immunoassay with signal enhancement based on nanogold-encapsulated poly(amidoamine) dendrimer-stimulated hydrogen evolution reaction.

A new electrochemical immunosensor with signal enhancement was designed for sensitive detection of disease-related protein (human carbohydrate antigen 19-9, CA 19-9 used in this case). The assay was carried out on a capture antibody-modified screen-printed carbon electrode with a sandwich-type mode by using detection antibody-functionalized nanogold-encapsulated poly(amidoamine) dendrimer (AuNP-PAAD). The AuNP-PAAD was first synthesized through the in situ reduction method and functionalized with the polyclonal rabbit anti-human CA 19-9 antibody. Upon target CA 19-9 introduction, a sandwiched immunocomplex could be formed between the capture antibody and detection antibody. Accompanying the AuNP-PAAD, the electrocatalytic activity of the carried gold nanoparticles toward the hydrogen evolution reaction (HER) allowed the rapid quantification of the target analyte on the electrode. The amplified electrochemical signal mainly derived from AuNP-catalyzed HER in an acidic medium. Under optimal conditions, the immuno-HER assay displayed a wide dynamic concentration range from 0.01 to 300 U mL(-1) toward target CA 19-9 with a detection limit (LOD) of 6.3 mU mL(-1). The reproducibility, precision, specificity and stability of our strategy were acceptable. Additionally, the system was further validated by assaying 13 human serum specimens, giving well matched results obtained from the commercialized enzyme-linked immunosorbent assay (ELISA) method.

Hybridization-induced Ag(I) dissociation from an immobilization-free and label-free hairpin DNA: toward a novel electronic monitoring platform.

A novel silver ion (Ag(+))-assisted hairpin DNA through C-Ag(+)-C coordination chemistry was designed for immobilization-free and label-free electrochemical monitoring of human immunodeficiency virus (HIV) DNA on a negatively charged indium-tin oxide electrode, based on hybridization-induced dissociation of silver ions from the hairpin DNA.

High-throughput analytical methodology of monoalkyl phthalate esters and the composite risk assessment with their parent phthalate esters in aquatic organisms and seawater.

A sensitive, robust, and highly efficient analytical methodology involving solid phase extraction coupled to ultra-high performance liquid chromatography tandem mass spectrometry was successfully established to detect 13 monoalkyl phthalate esters (MPAEs) in aquatic organisms and seawater. After the organisms were preprocessed using enzymatic deconjugation with ß-glucuronidase, extraction, purification, and qualitative and quantitative optimization procedures were performed. Under optimal conditions, the limits of detection varied from 0.07 to 0.88 µg/kg (wet weight) and 0.04-1.96 ng/L in organisms and seawater, respectively. Collectively, MPAEs achieved acceptable recovery values (91.0-102.7%) with relative standard deviations less than 10.4% and matrix effects ranging from 0.93 to 1.07 in the above matrix. Furthermore, MPAEs and phthalate esters were detected by the developed methodology and gas chromatography-triple quadrupole tandem mass spectrometer in practical samples, respectively. Mono-n-butyl phthalate and mono-iso-butyl phthalate were the most predominant congeners, accounting for 24.8-35.2% in aquatic organisms and seawater. Comprehensive health and ecological risks were higher after the MPAEs were incorporated than when phthalate esters were considered separately, and greater than their risk threshold. Therefore, the risks caused by substances and their metabolites in multiple media, with analogous structure-activity relationships, should be considered to ensure the safety of aquatic organisms and consumers.

Combining genome-wide association study and transcriptome analysis to identify molecular markers and genetic basis of population-asynchronous ovarian development in Coilia nasus.

Coilia nasus, a migratory fish species found in the middle and lower reaches of the Yangtze River and along offshore areas of China, possesses considerable aquacultural and economic potential. However, the species faces challenges due to significant variation in the gonadal development rate among females, resulting in inconsistent ovarian maturation times at the population level, an extended reproductive period, and limitations on fish growth rate due to ovarian prematurity. In the present study, we combined genome-wide association study (GWAS) and comparative transcriptome analysis to investigate the potential single nucleotide polymorphisms (SNPs) and candidate genes associated with population-asynchronous ovarian development in C. nasus. Genotyping of the female population based on whole-genome resequencing yielded 2 120 695 high-quality SNPs, 39 of which were suggestively associated with ovarian development. Of note, a significant SNP peak on LG21 containing 30 suggestively associated SNPs was identified, with cpne5a determined as the causal gene of the peak. Therefore, single-marker and haplotype association analyses were performed on cpne5a, revealing four genetic markers ( P<0.05) and seven haplotypes (r 2>0.9) significantly associated with the phenotype. Comparative transcriptome analysis of precociously and normally maturing individuals screened out 29 and 426 overlapping differentially expressed genes in the brain and ovary, respectively, between individuals of different body sizes. Integrating the GWAS and transcriptome analysis results, this study identified genes and pathways related to hypothalamic-pituitary-gonadal axis hormone secretion, extracellular matrix, angiogenesis, and gap junctions involved in population-asynchronous ovarian development. The insights gained from this study provide a basis for a deeper understanding of the molecular mechanisms underlying ovarian development in fish and may facilitate the genetic breeding of C. nasus strains exhibiting population-synchronous ovarian development in the future.

Transcriptome sequencing and metabolite analysis reveal the single and combined effects of microplastics and di-(2-ethylhexyl) phthalate on Peneaus vannamei.

Due to the rising usage of plastics, plastic debris are present throughout marine ecosystems and detrimentally affects marine biota. Additionally, plastics likely result in elusive toxicity effects due to addition of plasticizers. The aim of the present study was to reveal the potential effects and mechanism of microplastics (MPs), di-(2-ethylhexyl) phthalate (DEHP) and copollution of MPs and DEHP (MPs-DEHP) on Peneaus vannamei (P. vannamei) juveniles regarding oxidative stress, transcriptomics and metabolomics. MPs, DEHP and MPs-DEHP significantly induced the activities of superoxide dismutase (SOD) and catalase (CAT); MPs and DEHP have an antagonistic effect for malondialdehyde (MDA); suggesting that disorders of the antioxidant defence systems. 13, 133 and 58 differentially expressed genes and 21, 82 and 39 differentially expressed metabolites were responsible for the distinction of MPs, DEHP and MPs-DEHP groups, respectively. The combination of transcriptomic and metabolomic analyses showed that MPs, DEHP and MPs-DEHP exposure disturbed amino acid and lipid metabolism, and further induced inflammatory responses and dysfunction of purine metabolism. Furthermore, the presence of MPs might alleviate the biotoxicity of DEHP in P. vannamei. These findings provide new insights into the single and combined toxicological effects of MPs and additives for marine biota.

Highly selective molecularly imprinted-electrochemiluminescence sensor based on perovskite/Ru(bpy)32+ for simazine detection in aquatic products.

A novel molecularly imprinted electrochemiluminescence (MIECL) sensor based on the luminescence of molecularly imprinted polymer-perovskite (MIP-CsPbBr3) layer and Ru(bpy)32+ was fabricated for simazine detection. MIP-CsPbBr3 layers were immobilized onto the surface of glassy carbon electrode as the capture and signal amplification probe, and Ru(bpy)32+ and co-reactant tripropylamine exhibited stronger electrochemiluminescence (ECL) emission. Under optimal conditions, the ECL signal of the MIECL sensor was linearly quenched, with the logarithm of simazine concentration ranging from 0.1 µg/L to 500.0 µg/L, correlation coefficient of 0.9947, and limit of detection of 0.06 µg/L. The practicality of the developed MIECL sensor method for simazine determination in aquatic samples was validated. Excellent recoveries of 86.5 %-103.9 % with relative standard deviation below 1.6 % were obtained for fish and shrimp samples at three different spiked concentrations. The MIECL sensor exhibited excellent selectivity, sensitivity, reproducibility, accuracy, and precision for simazine determination in actual aquatic samples.

Development and application of tricolor ratiometric fluorescence sensor based on molecularly imprinted nanoparticles for visual detection of dibutyl phthalate in seawater and fish samples.

A tricolor ratiometric fluorescence sensor was fabricated by mixing blue- and red-emission molecularly imprinted quantum dots (MIP-QDs) with green-emission quantum dots at the optimal ratio. The MIP-QDs were synthesized by coating CdSe/ZnS QDs in polymer by inverse microemulsion method. Compared with single-emission or dual-emission sensors, the tricolor ratiometric fluorescence sensor provided a wider range of color variations for visual DBP detection. The ratio fluorescence value I530/(I450 + I630) of the tricolor ratiometric fluorescence sensor linearly changed within the concentration of 2.0-20.0 × 103 µg/L DBP. The correlation coefficient was 0.9910, and the limits of detection were 1.0 µg/kg and 0.65 µg/L in fish and seawater, respectively. Meanwhile, the fluorescence color gradually changed from purple to plum to pink to salmon to yellowish green and finally to green. The recoveries of DBP in fish and seawater were 84.3 %-91.4 % and 88.3 %-110.3 %, respectively. Moreover, no obvious differences were observed between the detection results of the tricolor ratiometric fluorescence sensor and gas chromatography-tandem mass spectrometry. The tricolor ratiometric fluorescence sensor constructed herein provides an ideal choice for rapid and intuitive DBP detection in environmental and aquatic products.

Organophosphate esters in the mariculture ecosystem: Environmental occurrence and risk assessments.

Most investigations on organophosphate esters (OPEs) are conducted predominantly in a separate biological or abiotic medium, and few joint analyses have been performed in the mariculture ecosystem based on yearly sampling. Herein, we investigated the occurrence, load estimation, phase distribution, source diagnostics, and risks of 20 OPEs in seawater, sediment, and aquaculture organisms from a typical mariculture area in China. The total of these OPEs (∑OPEs) ranged within 3.97-1068 ng/L, 0.39-65.5 ng/g (dw), and 4.09-16.3 ng/g (ww) in seawater, sediment and organisms, respectively. Chlorinated OPEs were the predominant congeners detected in seawater, whereas alkyl-OPEs were the leading contributors in sediment and biological samples. Seasonal variations of ∑OPEs in seawater were more distinct than those in sedimentary environments. Load estimation indicated that approximately 70% of the OPEs in the study area existed in the water bodies. Source identification performed using the U.S. EPA positive matrix factorization indicated that polyurethane foam/plastics and hydraulic oil made the greatest contributions in seawater, whereas chemical production was the predominant source in sediment. Indices of ecological and health risks of OPEs were lower than their risk threshold, indicating that the OPEs detected in this study posed a low risk to the aquatic environment and human health.

Ultrasensitive electrochemiluminescence sensor based on perovskite quantum dots coated with molecularly imprinted polymer for prometryn determination.

A highly effective molecularly imprinted electrochemiluminescence sensor was constructed for prometryn determination in environmental and biological samples by using perovskite quantum dots coated with a molecularly imprinted silica layer (MIP/CsPbBr3-QDs) as the recognition and response element. MIP/CsPbBr3-QDs were immobilized on a glassy carbon electrode (GCE) through electropolymerization, and the electrochemiluminescence (ECL) response of MIP/CsPbBr3-QDs could be motivated under the condition of H2O2 as co-reactant. ECL signal was selectively quenched with prometryn by hindering electron transfer and directly proportional to the logarithm of prometryn concentration (0.10-500.0 µg/L) with a correlation coefficient of 0.9960. Limits of detection in fish and seawater samples were 0.010 µg/kg and 0.050 µg/L, respectively. Excellent recoveries of 88.0%-106.0% were acquired for fish and seawater samples with a relative standard deviation below 4.2%. The constructed MIECL sensor based on MIP/CsPbBr3-QDs showed good stability, accuracy, and precision for sensitive detection of prometryn in aquaculture products and environmental samples.

Contaminant occurrence, mobility and ecological risk assessment of phthalate esters in the sediment-water system of the Hangzhou Bay.

The pollution characteristics, spatiotemporal variation, sediment-water partitioning, and potential ecological risk assessment of phthalate esters (PAEs) in the sediment-seawater system of the Hangzhou Bay (HZB) in summer and autumn were researched. The sum of the concentrations of the 10 PAEs in seawater ranges from 7305 ng/L to 22,861 ng/L in summer and from 8100 ng/L to 33,329 ng/L in autumn, with mean values of 15,567 ± 4390 and 17,884 ± 6850 ng/L, respectively. The Σ16PAEs in the sediments are between 118 and 5888 µg/kg and 145 and 4746 µg/kg in summer and autumn, respectively. The level of PAEs in seawater varies with the seasons, but it is relatively stable in the sediments. Di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) are the predominant PAE congeners in the HZB. The DnBP and DiBP concentrations in seawater are greater than the DEHP concentration, which is the opposite in the sediments. The sediment-seawater equilibrium distribution study indicates that the PAEs with medium molecular weights, such as DiBP, butyl benzyl phthalate, and DnBP, are near dynamic equilibrium in the sediment-seawater system; PAEs with high molecular weights (e.g., di-n-octyl phthalate and DEHP) tend to transfer from water to the sediments; and PAEs with low molecular weights (e.g., dimethyl phthalate, diethyl phthalate, and diamyl phthalate) tend to spread to seawater. The risk assessment results in seawater indicate that DEHP and DiBP might pose high potential risks to sensitive organisms, and DnBP might exhibit medium ecological risks. In the sediment, DiBP might display a high potential risk to fish, and the potential risk of DEHP is high in several sites.

A comprehensive study of the effects of phthalates on marine mussels: Bioconcentration, enzymatic activities and metabolomics.

In this study, marine mussels (Mytilus coruscus) were exposed to three typical PAEs (dimethyl phthalate [DMP], dibutyl phthalate [DBP] and di(2-ethylhexyl) phthalate [DEHP]) at a range of doses for different times to investigate the ecotoxicological effects. The accumulation of the three PAE congeners in M. coruscus exhibited the following trend: DEHP > DBP > DMP. The antioxidant response of mussel gonadal tissue was enhanced with increasing concentrations of PAEs. For the DBP and DEHP treatment groups, glutathione (GSH) worked in concert with antioxidant enzymes to protect cells against reactive oxygen species (ROS), while GSH played a prominent antioxidant role in the DMP-treated group. The metabolomics results revealed that PAE exposure disrupted the metabolic balance of mussels. Overall, PAEs affect the amino acid metabolism, lipid metabolism, energy metabolism, osmoregulation and nerve activities of mussels. Our results provide further insight into the toxicological effects of PAEs on marine organisms.

Aquaculture-derived distribution, partitioning, migration, and transformation of atrazine and its metabolites in seawater, sediment, and organisms from a typical semi-closed mariculture bay.

Atrazine (ATR) is one of the most commonly used herbicides that could directly impair the growth and health of organisms in mariculture areas and adversely affect human health through the food chain. This study investigated the contaminant occurrence, migration, and transformation of ATR and three of its chlorinated metabolites, namely deethylatrazine (DEA), deisopropylatrazine (DIA), and didealkylatrazine (DDA), in surface seawater, sediment, and aquatic organisms from the Xiangshan Harbor. ATR was detected in all samples, while DIA and DDA were only respectively detected in aquatic and seawater samples. The distribution of ATR and its metabolites presented different patterns depending on the geographic location and showed a higher level in the aquaculture area than that in the non-aquaculture area. The bioaccumulation of ATR in aquaculture organisms showed that benthic organisms, such as Ditrema, and Sinonovacula constricta (Sin), had increased levels. The ecological risks indicated that ATR posed medium or high risks to algae in the water phase of the study area. The microcosm experiment showed that the main fate of ATR in the simulated microenvironment was sedimentation, which followed the first-order kinetic equation. The ATR in the sediment could be enriched 3-5 times in Sin, and its major metabolites were DEA and DIA.

Probing the contamination characteristics, mobility, and risk assessments of typical plastic additive-phthalate esters from a typical coastal aquaculture area, China.

Contamination characteristics, equilibrium partitioning and risk assessment of phthalate esters (PAEs) were investigated in seawater, sediment and biological samples collected from the Xiangshan Bay area during an annual investigation between January and November 2019. PAE concentrations detected in the mariculture environment in surface seawater, sediment, and biological samples were 172-3365 ng/L, 190-2430 µg/kg (dry weight [dw]), and 820-4926 µg/kg (dw), respectively. The dominant congeners in different media included di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP). The inner bay and the bay mouth were the gathering area of PAEs and heavily influenced by the mariculture activities, river inputs, and anthropogenic activities. The bioaccumulation of PAEs demonstrated benthic feeding fishes with relatively high trophic levels concentrated high levels of phthalates. The mobility of PAEs in sediment-seawater showed that the transfer tendency of low-molecular weight species was from the sediment to the water, which was in contrast with those of high-molecular weight PAEs. DEHP, DiBP and DnBP had various degrees of ecological risks in the aquatic environment, whereas only the DiBP posed potential risks in sediments. The current assessment of carcinogenic and noncarcinogenic risks posed by fish consumption were within acceptable limits for humans.

Comparative evaluation of high-density polyethylene and polystyrene microplastics pollutants: Uptake, elimination and effects in mussel.

The high-density polyethylene (HDPE) and the polystyrene (PS), which are typical microplastic contaminants, are frequently detected in the environment and have potential hazard to environmental health. In this study, the accumulation, elimination, tissue distribution and potential effects of the HDPE and the PS in the mussels (Mytilus galloprovincialis) were evaluated. The HDPE and the PS were found in various tissues (digestive gland > gill > gonad ≈ muscle) with no difference in distribution patterns. The accumulation of the HDPE and the PS rapidly increased in the first 48 h exposure, and the accumulation of HDPE was higher than that of PS. After 144 h of elimination, most of the HDPE and the PS were cleared by mussels. In addition, the activities of superoxide dismutase (SOD), catalase (CAT) and the content of oxidized glutathione considerably increased, indicating that the HDPE and the PS induced oxidative stress and prevented oxidative damage in elimination. The metabolomic analysis suggested that exposure to HDPE and PS induced alterations in the metabolic profiles of mussel. Differential metabolites were involved in energy metabolism, lipid metabolism, tricarboxylic acid cycle and neurotoxic response., and Meanwhile, the PS had a lower effect on mussel metabolism during elimination, but the effect of HDPE was increased. Overall, this study elucidated that the HDPE and the PS caused adverse effects on the mussels and provided insights toward understanding the hazard of different microplastics on aquatic organisms.

Platinum nanozyme-encapsulated poly(amidoamine) dendrimer for voltammetric immunoassay of pro-gastrin-releasing peptide.

An innovative electrochemical immunosensing platform was designed for the sensitive monitoring of lung cancer biomarker (pro-gastrin-releasing peptide; ProGRP) by using platinum nanoparticles encapsulated inside dendrimers (PtDEN) as enzymatic mimics for the signal amplification. PtDEN nanocomposites were prepared through a simple chemical reduction method with the assistance of NaBH4. Thereafter, PtDEN-labeled anti-ProGRP secondary antibody was launched for the detection of target analyte with a sandwich-type assay format on anti-ProGRP capture antibody-modified screen-printed carbon electrode. Accompanying formation of immunocomplex, the labeled PtDENs electrochemically oxidized 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to produce a well-defined voltammetric signal within the applied potentials. Thanks to the high-efficient catalytic efficiency of platinum nanoparticles and high-loading ability of dendrimer, improved analytical features were acquired with PtDENs relative to platinum nanoparticles alone. Using PtDENs labeling strategy, the properties and factors influencing the analytical performance of electrochemical immunosensor were studied in detail. The strong bioconjugation of antibodies with the PtDENs caused a good repeatability and intermediate precision down to 7.64%. Under optimum conditions, the electrochemical immunosensor exhibited a dynamic linear range of 0.001-10 ng mL-1 ProGRP with a detection limit of 0.86 pg mL-1. Good selectivity and relatively long-term stability (>6 months) were achieved for target ProGRP. Significantly, the acceptable accuracy was gotten for analysis of ProGRP in human serum specimens referring to commercially available human ProGRP enzyme-linked immunosorbent assay (ELISA) method.