Enhanced Label-Free Photoelectrochemical Strategy for Pollutant Detection: Using Surface Oxygen Vacancies-Enriched BiVO4 Photoanode.

Label-free photoelectrochemical sensors have the advantages of high sensitivity and a simple electrode structure. However, its performance is greatly limited due to the photoactive materials' weak photoactivity and poor stability. Herein, a robust homogeneous photoelectrochemical (PEC) aptasensor has been constructed for atrazine (ATZ) based on photoetching (PE) surface oxygen vacancies (Ov)-enriched Bismuth vanadate (BiVO4) (PE-BVO). The surface of the Ov improves the carrier separation ability of BiVO4, thus providing a superior signal substrate for the sensor. A thiol molecular layer self-assembled on PE-BVO acts as a blocker, while 2D graphene acts as a signal-on probe after release from the aptamer-graphene complex. The fabricated sensor has a wide linear detection range of 0.5 pM to 10.0 nM and a low detection limit of 0.34 pM (S/N = 3) for ATZ. In addition, it can efficiently work in a wide pH range (3-13) and high ionic strength (∼6 M Na+), which provides promising opportunities for detecting environmental pollutants under complex conditions.

Biological impact and therapeutic potential of a novel camptothecin derivative (FLQY2) in pancreatic cancer through inactivation of the PDK1/AKT/mTOR pathway.

BACKGROUND: Camptothecin (CPT), a pentacyclic alkaloid with antitumor properties, is derived from the Camptotheca acuminata. Topotecan and irinotecan (CPT derivatives) were first approved by the Food and Drug Administration for cancer treatment over 25 years ago and remain key anticancer drugs today. However, their use is often limited by clinical toxicity. Despite extensive development efforts, many of these derivatives have not succeeded clinically, particularly in their effectiveness against pancreatic cancer which remains modest. AIM OF THE STUDY: This study aimed to evaluate the therapeutic activity of FLQY2, a CPT derivative synthesized in our laboratory, against pancreatic cancer, comparing its efficacy and mechanism of action with those of established clinical drugs. METHODS: The cytotoxic effects of FLQY2 on cancer cells were assessed using an MTT assay. Patient-derived organoid (PDO) models were employed to compare the sensitivity of FLQY2 to existing clinical drugs across various cancers. The impact of FLQY2 on apoptosis and cell cycle arrest in Mia Paca-2 pancreatic cancer cells was examined through flow cytometry. Transcriptomic and proteomic analyses were conducted to explore the underlying mechanisms of FLQY2's antitumor activity. Western blotting was used to determine the levels of proteins regulated by FLQY2. Additionally, the antitumor efficacy of FLQY2 in vivo was evaluated in a pancreatic cancer xenograft model. RESULTS: FLQY2 demonstrated (1) potent cytotoxicity; (2) superior tumor-suppressive activity in PDO models compared to current clinical drugs such as gemcitabine, 5-fluorouracil, cisplatin, paclitaxel, ivosidenib, infinitinib, and lenvatinib; (3) significantly greater tumor inhibition than paclitaxel liposomes in a pancreatic cancer xenograft model; (4) robust antitumor effects, closely associated with the inhibition of the TOP I and PDK1/AKT/mTOR signaling pathways. In vitro studies revealed that FLQY2 inhibited cell proliferation, colony formation, induced apoptosis, and caused cell cycle arrest at nanomolar concentrations. Furthermore, the combination of FLQY2 and gemcitabine exhibited significant inhibitory and synergistic effects. CONCLUSION: The study confirmed the involvement of topoisomerase I and the PDK1/AKT/mTOR pathways in mediating the antitumor activity of FLQY2 in treating Mia Paca-2 pancreatic cancer. Therefore, FLQY2 has potential as a novel therapeutic option for patients with pancreatic cancer.

Copper Peroxide Nanodots Encapsulated in a Metal-Organic Framework for Self-Supplying Hydrogen Peroxide and Signal Amplification of the Dual-Mode Immunoassay.

The necessary step of directly adding hydrogen peroxide (H2O2) into the detection system in traditional immunoassays hampers their applications as a portable device for point-of-care analysis due to the unstable liquid form of H2O2. Herein, a strategy of self-supplying H2O2 and signal amplification triggering by copper peroxide nanodots encapsulated (CPNs) in metal-organic frameworks (ZIF-8) was proposed in an immunoassay for dual-signal detection of bisphenol A (a typical emerging organic pollutant), which was further fabricated as a lab-in-a-tube device integrated with a smartphone sensing platform. Herein, CPNs@ZIF-8 was modified on the antibody against bisphenol A; after the competitive binding of analytes, coating antigens, and antibodies, the released H2O2 and Cu2+ from encapsulated CPNs under the acidic condition will trigger a Fenton-like reaction to generate ·OH for oxidization of TMB; meanwhile, Cu2+ could quench the fluorescence of GSH-Au NCs, resulting in dual-mode signals for measurements. Most importantly, self-supplying H2O2 with high stability was undertaken by CPNs, and the remarkably increased signal molecule (CPN) loading was ascribed to the excellent capacity of metal-organic frameworks (ZIF-8). In addition, good recoveries were obtained from a colorimetric/fluorescent dual-mode strategy. The constructed device demonstrated great potential as a universal platform for rapid detection of various environmental contaminants using corresponding antibodies relying on its performance of satisfactory stability, sensitivity, and accuracy.

Simultaneous determination of 31 endocrine disrupting chemicals in fish plasma by solid-phase extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry.

Solid phase extraction combined with ultra-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 31 endocrine-disrupting chemicals in fish plasma. The strong anion exchange/primary-secondary amine cartridge and the mixed cation exchange cartridge were used in tandem instead of using a single mixed cation exchange cartridge for sample purification. Suitable eluents were selected for each of the two cartridges: 4.5% ammonia/acetonitrile solution for cartridges in tandem and acetone:n-hexane (V:V = 3:7) for the strong anion exchange/primary-secondary amine cartridge alone. With this optimized Solid phase extraction method, the recoveries of 31 endocrine disrupting chemicals were between 43.0% and 131.3%, the method detection limits were 0.45 to 1.35 ng/ml, and the limits of quantitation were 1.50-4.50 ng/ml. The innovative pretreatment method that connects two cartridges in tandem is well positioned to mitigate the matrix effects of fish plasma, thereby improving the accuracy of multiclass endocrine-disrupting chemicals determination. The significance of this method is to facilitate the application of the fish plasma model for the environmental risk assessment of endocrine-disrupting chemicals.

Electrochemical Biosensor Based on Tetrahedral DNA Nanostructures and G-Quadruplex-Hemin Conformation for the Ultrasensitive Detection of MicroRNA-21 in Serum.

MicroRNAs (miRNAs) play important roles as significant biomarkers in disease diagnostics. Here, an electrochemical biosensor was developed for the quick, sensitive, and specific detection of miRNAs from human-serum samples using three-dimensional (3D) DNA tetrahedron-structured probes (TSPs) and duplex-specific nuclease (DSN). The designed TSPs were composed of a recognition sequence that corresponded to a target miRNA and a G-quadruplex sequence that was combined with hemin to mimic the biocatalytic functions for H2O2 reduction and l-cysteine oxidation. After hybridization with miRNA, the TSPs were immobilized on the Au electrode to shape the DNA-RNA double strands, which could be discriminated by DSN for hydrolysis of the DNA in the heteroduplexes to generate significant change in the reduction currents. Under optimal conditions, the biosensor showed a wide linear response ranging from 0.1 fM to 0.1 pM, with a low detection limit of 0.04 fM. Meanwhile, the method showed acceptable accuracy and precision for the determination of miRNAs in serum after a series of assessments.

Simultaneous determination of 29 pharmaceuticals in fish muscle and plasma by ultrasonic extraction followed by SPE-UHPLC-MS/MS.

A confirmatory method for the simultaneous detection of 29 pharmaceuticals in fish muscle and plasma was developed by using solid-phase extraction combined with ultra-high performance liquid chromatography and tandem mass spectrometry. Fish samples were extracted with methanol and enriched using Oasis HLB solid-phase extraction columns in one step. Twenty-nine target pharmaceuticals were quantified by the internal standard method and the calibration curves showed good linearity in a wide range with determination coefficients of greater than 0.913. The detection limits of the pharmaceuticals ranged from 0.01 to 2.00 µg/kg (µg/L). The applicability of the method was checked by precision and recovery experiments. The average recoveries of the 29 pharmaceuticals were between 61 and 111%, and all the relative standard deviations were below 25%. Our reported method has been demonstrated to be sensitive, convenient, rapid, and reliable for the simultaneous determination of 29 pharmaceuticals in fish muscle and plasma. Real sample determination showed that 25 and 9 of the 29 compounds were detected in fish muscle and plasma, respectively.

Effect of subcellular distribution on nC60 uptake and transfer efficiency from Scenedesmus obliquus to Daphnia magna.

The potential uptake and trophic transfer ability of nanoparticles (NPs) in aquatic organisms have not been well understood yet. There has been an increasing awareness of the subcellular fate of NPs in organisms, but how the subcellular distribution of NPs subsequently affects the trophic transfer to predator remains to be answered. In the present study, the food chain from Scenedesmus obliquus to Daphnia magna was established to simulate the trophic transfer of fullerene aqueous suspension (nC60). The nC60 contaminated algae were separated into three fractions: cell wall (CW), cell organelle (CO), and cell membrane (CM) fractions, and we investigated the nC60 uptake amounts and trophic transfer efficiency to the predator through dietary exposure to algae or algal subcellular fractions. The nC60 distribution in CW fraction of S. obliquus was the highest, following by CO and CM fractions. nC60 uptake amounts in D. magna were found to be mainly relative to the NPs' distribution in CW fraction and daphnia uptake ability from CW fraction, whereas the nC60 trophic transfer efficiency (TE) were mainly in accordance with the transfer ability of NPs from the CO fraction. CW fed group possessed the highest uptake amount, followed by CO and CM fed groups, but the presence of humic acid (HA) significantly decreased the nC60 uptake from CW fed group. The CO fed groups acquired high TE values for nC60, while CM fed groups had low TE values. Moreover, even though CW fed group had a high TE value; it decreased significantly with the presence of HA. This study contributes to the understanding of fullerene NPs' dietary exposure to aquatic organisms, suggesting that NPs in different food forms are not necessarily equally trophically available to the predator.

Solid-phase extraction coupled with ultra high performance liquid chromatography and electrospray tandem mass spectrometry for the highly sensitive determination of five iodinated X-ray contrast media in environmental water samples.

A highly sensitive method based on solid-phase extraction and ultra high performance liquid chromatography with electrospray tandem mass spectrometry has been developed for simultaneous determination of five iodinated X-ray contrast media in environmental water samples. Various solid-phase extraction cartridges have been evaluated and a combination of LiChrolute EN and ENVI-Carb solid phase extraction cartridges was selected for sample enrichment. The method was comprehensively validated on ground water, tap water, surface water, drinking water, and waste water by the conventional procedures: linearity, method detection limits, accuracy and precision, matrix effects. Good linearity (R(2) > 0.999), low detection limits (0.4-8.1 ng/L), satisfactory recoveries (55.1-109.5%) and precision (0.8-10.0% for intra-day precisions and 0.6-16.5% for inter-day precisions) were obtained for all the target compounds. Iopamidol, iohexol, and diatrizoate in some matrices were affected by matrix effects, which were slightly eased by using the isotope-labeled internal standard. The developed method was successfully applied for real samples collected in Shanghai, China, with detected concentrations up to 2200 ± 200 and 9000 ± 1000 ng/L for iohexol and iopamidol, respectively.

Combined effects of pH and dissolved organic matter on the availability of pharmaceuticals and personal care products in aqueous environment.

The interaction between pharmaceuticals and personal care products (PPCPs) with dissolved organic matter (DOM) can alter their bioavailability and toxicity. Nevertheless, little is known about how pH and DOM work together to affect the availability of PPCPs. This study investigated the impact of pH and DOM on the availability of seven PPCPs, namely Carbamazepine, Estrone, Bisphenol A, Testosterone Propionate, Triclocarban, 4-tert-Octylphenol and 4-n-Nonylphenol, using negligible depletion solid-phase microextraction (nd-SPME). The uptake kinetics of PPCPs by the nd-SPME fibers increased proportionally with DOM concentrations, likely due to enhanced diffusive conductivity in the unstirred water layer. At neutral pH, the partitioning coefficients of PPCPs for Humic Acid (log KDOC 3.87-5.25) were marginally higher than those for Fulvic Acid (log KDOC 3.64-5.11). Also, the log KDOC values correlated linearly with the log DOW (pH 7.0) values of PPCPs, indicating a predominant role for hydrophobic interactions in the binding of DOM and PPCPs. Additionally, specific interactions like hydrogen bonding, π-π, and electrostatic interactions occur for certain compounds, influenced by the polarity and spatial conformation of the compounds. For these ionizable PPCPs, the log DDOC values exhibit a strong dependence on pH due to the dual influence of pH on both DOM and PPCPs. The log DDOC values rose from pH 1.0 to 3.0, peaked at pH 5.0 to 9.0, and then (sharply) declined from 11.0 to 13.0. The reasons are that in strong acidic circumstances, the coiled and compressed shape of DOM inhibits the hydrophobic interaction, whereas in strong alkaline conditions, significant electrostatic repulsion reduces the sorption. This study reveals that the effects of DOM on the bioavailability of PPCPs are dependent on both pH and the specific compound involved.

Aptamer molecular gate functionalized mesoporous SiO2@MB controlled-release system for pollutant detection using Ti(â ¢) self-doped TiO2 NTs as active photoanode coupled with electrostatic modulation.

Atrazine (ATZ) is a widely used herbicide that can cause serious harm to organisms and ecosystems. An immobilization-free photoelectrochemical (PEC) aptasensor has been herein developed for ATZ based on aptamer molecular gate functionalized mesoporous SiO2@MB controlled release system. Compared with traditional immobilization-based sensors, immobilization-free sensors (IFSs) avoid the modification of the recognition element on the electrode surface. Mesoporous SiO2 with large surface area and good biocompatibility can be used as nanocontainers to stably encapsulate the signal shuttle molecule methylene blue (MB). The bifunctional aptamer (APT) is used not only as the recognition element for ATZ but also as the signal switch to block or release MB. In the presence of ATZ, the specific recognition between ATZ and APT will cause the detachment of APT from the surface of SiO2, thus the molecular gate will open and release MB. Due to pH modulation, the positively charged MB can reach the surface of the negatively charged Ti(III) self-doped TiO2 NTs (Ti(III)-TiO2 NTs) electrode to act as an electron donor, which increases the photocurrent. The immobilization-free aptasensor has shown ultrasensitive detection of ATZ with a wide linear range from 1.0 pM to 100.0 nM and a low detection limit of 0.1 pM. In addition, the sensor has excellent selectivity, stability and anti-interference ability, and has been used in real water sample analysis successfully. This strategy has provided a new idea for the design of advanced immobilization-free PEC sensors for environmental pollutant detection.

The distributions, removals and estrogenic effects of selected endocrine disrupting chemicals in two drinking water factories in China.

The distributions and effects of 31 selected endocrine disrupting chemicals (EDCs) in two drinking water factories were analyzed in this study. The distributions of EDCs were analyzed by solid phase extraction (SPE) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS). The concentrations of these EDCs were from lower than the LOD (limit of detection) to 23.13 ng L (- 1) in the samples; most of them were lower than 1 ng L (- 1). The highest concentration (23.13 ± 1.45 ng L (- 1)) was detected in the raw water. Twenty-six chemicals were found in the raw water and only five in the finished water of drinking water factory A, while 25 chemicals were detected in the raw water and two in the finished water of drinking water factory B. The results indicate that most of the EDCs can be removed by the water treatment process. In the advanced treatment process, the ozonation processes have the highest removal efficiency. Separate analyses in May and September show similar results. Apart from the chemical analysis, yeast strain transformed when the estrogen receptor α (ERα) gene was employed to test the estrogenic effects of the water samples. Due to the low concentrations of these EDCs, no significant estrogenic effects were found from the samples.

Effects of nanoplastics and microplastics on the availability of pharmaceuticals and personal care products in aqueous environment.

Nanoplastics (NPs) and microplastics (MPs) could act as potential carriers for pharmaceuticals and personal care products (PPCPs) and alter the bioavailability in the aquatic environment. The effects of NPs and MPs of polystyrene (PS) and polyethylene (PE) on the availability of five PPCPs including carbamazepine, bisphenol A, estrone, triclocarban and 4-tert-octylphenol were investigated by negligible depletion solid- phase microextraction (nd-SPME). The freely dissolved concentrations of PPCPs decreased with the increasing concentrations of NPs/MPs. The overall order of the sorption coefficients (logKNP / logKMP) of PPCPs was as follows: 100 nm PS > 50 nm PS > 1 µm PS > 100 µm PS > 100 µm PE. Sorption of PPCPs by NPs was generally 1-2 orders of magnitude stronger than to MPs. The log KNP / log KMP values (3.16-5.21) increased with the log KOW (2.45-5.28) of PPCPs, however, linear correlation was only observed between log KMP and log KOW. The particle size, specific surface area, aggregation state as well as hydrophobicity played an important role in the sorption. Coexistence of fulic acid (FA) with NPs inhibited the sorption due to the fouling of FA on NPs. This study suggests that sorption of PPCPs to MPs/NPs could reduce bioavailability of PPCPs in the aquatic environment.

Effects of carbamazepine on the central nervous system of zebrafish at human therapeutic plasma levels.

The fish plasma model (FPM) facilitated the environmental risk assessment of human drugs by using existing data on human therapeutic plasma concentrations (HTPCs) and predicted fish plasma concentrations (FPCs). However, studies on carbamazepine (CMZ) with both the mode of action (MOA) based biological effects at molecular level (such as neurotransmitter and gene level) and measured FPCs are lacking. Bioconcentration of CMZ in adult zebrafish demonstrated that the FPM underestimated the bioconcentration factors (BCFs) in plasma at environmental CMZ exposure concentrations (1-100 µg/L). CMZ significantly increased Glu and GABA, decreased ACh and AChE as well as inhibited the transcription levels of gabra1, grin1b, grin2b, gad1b, and abat when the actual FPCs were in the ranges of 1/1000 HTPC to HTPC. It is the first read-across study of CMZ integrating MOA-based biological effects at molecular level and FPCs. This study facilitates model performance against a range of different drug classes.

Encapsulating gold nanoclusters into metal-organic frameworks to boost luminescence for sensitive detection of copper ions and organophosphorus pesticides.

Gold nanoclusters (Au NCs) with luminescence property are emerging as promising candidates in fluorescent methods for monitoring contaminants, but low luminescence efficiency hampers their extensive applications. Herein, GSH-Au NCs@ZIF-8 was designed by encapsulating GSH-Au NCs with AIE effect into metal-organic frameworks, achieving high luminescence efficiency and good stability through the confinement effect of ZIF-8. Accordingly, a fluorescent sensing platform was constructed for the sensitive detection of copper ions (Cu2+) and organophosphorus pesticides (OPs). Firstly, the as-prepared GSH-Au NCs@ZIF-8 could strongly accumulate Cu2+ due to the adsorption property of MOFs, accompanied by a significant fluorescence quenching effect with a low detection limit of 0.016 µM for Cu2+. Besides, thiocholine (Tch), the hydrolysis product of acetylthiocholine (ATch) by acetylcholinesterase (AchE), could coordinate with Cu2+ by sulfhydryl groups (-SH), leading to a significant fluorescence recovery, which was further used for the quantification of OPs owing to its inhibition to AChE activity. Furthermore, a hydrogel sensor was explored to accomplish equipment-free, visual, and quantitative monitoring of Cu2+ and OPs by a smartphone sensing platform. Overall, this work provides an effective and universal strategy for enhancing the luminescence efficiency and stability of Au NCs, which would greatly promote their applications in contaminants monitoring.

Ionic liquid-based single-drop liquid-phase microextraction combined with high-performance liquid chromatography for the determination of sulfonamides in environmental water.

A simple, rapid and environment-friendly technique of single-drop liquid-phase microextraction has been developed for the determination of sulfonamides in environmental water. Several important parameters including stirring rate, extraction solvent, extraction pH, salinity and extraction time were optimized to maximize the extract efficiency. Extraction solvent 1-octyl-3-methylimidazolium hexafluorophosphate [C(8) MIM][PF(6) ] ionic liquid showed better extraction efficiency than 1-butyl-3-methylimidazolium hexafluorophosphate [C(4) MIM][PF(6) ] and 1-octanol. The optimum experimental conditions were: pH, 4.5; sodium chloride content, 36% w/v; extraction time, 20 min. This method provided low detection limits (0.5-1 ng/mL), good repeatability (the RSD ranging from 4.2 to 9.9%, n=5) and wide linear range (1-1500 ng/mL), with determination coefficients (r(2) ) higher than 0.9989 for all the target compounds. Real sample analysis showed relative recoveries between 63.5 and 115.8% for all the target compounds.

Self-powered aptasensor for picomole level pollutants based on a novel enzyme-free photofuel cell.

Atrazine (ATZ) is a highly toxic chlorine-containing aromatic structural triazine endocrine disruptor. Due to its chemical stability and electrochemical inertness, it is of great challenge and significance to establish a simple, portable, and in situ electrochemical sensor for ATZ. In the present work, a self-powered aptasensor (SPA) based on a novel enzyme-free photofuel cell (PFC) is successfully developed for ATZ for the first time. The designed SPA is constructed by the Ti-Fe-O nanotubes/nickel hydroxide (Ti-Fe-O NTs/Ni(OH)2) photoanode and Au/aptamer (Au/Apt) cathode, responsible for the spontaneous generation of electrons and specific recognition of ATZ, respectively. It is worth noting that Ti-Fe-O NTs on the photoanode can exhibit good visible-light absorption property, and modified Ni(OH)2 further enhances the photo-generated carrier separation and improves the output power generation of the SPA. The recognition is set at the cathode to ensure the detection of ATZ and the anti-interference ability. Under the separation mode, the constructed SPA has a high output power (390 µW cm-2), much better than most previous reports. It can further show specific recognition of ATZ with prominent sensitivity and a limit of detection (LOD) as low as 5.4 pM. Moreover, it has been applied to the real water sample analysis with satisfactory results. A promising self-powered sensing platform based on an enzyme-free PFC has therefore been provided for picomole level pollutants with high sensitivity and outstanding selectivity.

Oxidized nanoscale zero-valent iron changed the bioaccumulation and distribution of chromium in zebrafish.

Influences of colloidal stabilities of nanoparticles (NPs) on the bioaccumulation of co-existing pollutants remains largely unknown. In this study, two oxidation products of nanoscale zero-valent iron (nZVI) with totally varied colloidal stabilities, termed highly oxidized nZVI (HO-nZVI) and lowly oxidized nZVI (LO-nZVI), were exposed to zebrafish with chromium (Cr); this approach was used to investigate the impacts of colloidal stability of oxidized nZVI on the bioaccumulation of Cr in zebrafish. A significant increase in the Cr and NP content in the viscera of fish in the presence of the oxidized nZVI after 20 days of exposure was confirmed, which indicated that Cr was consumed by fish through the uptake of the NPs. Furthermore, a significantly higher level of the HO-nZVI accumulated in the viscera in contrast to LO-nZVI, which suggested that the colloidal stability of NP is a crucial factor when evaluating the accessibility of NPs to zebrafish. Thus, HO-nZVI induced a significantly stronger enhancement of Cr content in fish than LO-nZVI. Our results suggest that oxidized nZVI will act as the carrier of co-existing heavy metals and change the transportation and distribution of heavy metals in zebrafish; moreover, the colloidal stability of NP will have a significant influence on the bioaccumulation of coexisting Cr.

Bioaccessibility evaluation of pharmaceuticals in market fish with in vitro simulated digestion.

The consumption of pharmaceuticals-contaminated aquatic products could pose risks to human health, and risk assessments considering bioaccessibility can provide better dietary recommendations. In this study, the bioaccessibility of 6 pharmaceuticals (sulfadiazine (SD), sulfapyridine (SPD), roxithromycin (ROX), tylosin (TYL), diclofenac (DIC) and carbamazepine (CMZP)) in several fish species collected from Shanghai markets was evaluated using in vitro simulated digestion. The total mixed pharmaceuticals concentration in freshwater fish were lower than those in marine fish, and statistics showed that the total concentrations of SD, SPD and CMZP in freshwater fish were significantly lower than those of marine fish (p < 0.05). The bioaccessible concentration of each pharmaceutical accounted for 26.3% (TYL) to 101.5% (CMZP) of the total concentration in market fish (n = 70). The bioaccessibility of 6 pharmaceuticals in species of fish was 18.8% (cutlassfish) to 99.6% (bream), which may be related to the physical-chemical properties of the pharmaceutical and the characteristics of the matrix (e.g. lipid content). According to health risk assessments, the consumption of market fish in Shanghai posed no remarkable risk to human health (hazard quotient < 0.099). Ignoring the bioaccessibility of pharmaceuticals in aquatic products might overestimate the human health risks by dietary exposure.

A Lab-in-a-Syringe Device Integrated with a Smartphone Platform: Colorimetric and Fluorescent Dual-Mode Signals for On-Site Detection of Organophosphorus Pesticides.

Herein, a portable lab-in-a-syringe device integrated with a smartphone sensing platform was designed for rapid, visual quantitative determination of organophosphorus pesticides (OPs) via colorimetric and fluorescent signals. The device was chiefly made up of a conjugate pad labeled with cetyltrimethylammonium bromide-coated gold nanoparticles (CTAB-Au NPs) and a sensing pad modified by ratiometric probes (red-emission quantum dots@SiO2 nanoparticles@green-emission quantum dots, rQDs@SiO2@gQDs probe), which was assembled through a disposable syringe and reusable plastic filter. In the detection system, thiocholine (Tch), the hydrolysis product of thioacetylcholine (ATch) by acetylcholinesterase (AchE), could trigger the aggregation of CTAB-Au NPs, resulting in a significant color change from red to purple. Then, CTAB-Au NPs flowed vertically upward and bound to the rQDs@SiO2@gQDs probe on the sensing pad, reducing the fluorescence resonance energy transfer effect between CTAB-Au NPs and gQDs. Meanwhile, rQDs embedded in SiO2 NPs remained stable as internal reference fluorescence, achieving a color transition from red to green. Thus, based on the inhibition of AChE activity by OPs, a colorimetric and fluorescent dual-mode platform was constructed for on-site detection of OPs. Using glyphosate as a model, with the support of a color recognizer application (APP) on a smartphone, the ratio of red and green channel values could be utilized for accurate OP quantitative analysis ranging from 0 to 10 µM with a detection limit of 2.81 nM (recoveries, 90.8-122.4%; CV, 1.2-3.4%). Overall, the portable lab-in-a-syringe device based on a smartphone sensing platform integrated sample monitoring and result analysis in the field, implying great potential for on-site detection of OPs.

Toxicity prediction of antibiotics on luminescent bacteria, Photobacterium phosphoreum, based on their quantitative structure-activity relationship models.

Acute toxicity (EC50₋30 min) and chronic toxicity (EC50₋24 h) of 21 antibiotics on Photobacterium phosphoreum was observed and Quantitative structure-activity relationship (QSAR) models were developed, respectively. By comparing these two QSAR models, the following model was established, log(1/EC50₋24 h) = 1.8283 + 1.1503log(1/EC 50₋30 min) + 0.2872Elomo - 0.0901DM + 0.0003PMIZ + 0.0088PSA - 0.0382SD, r² = 0.8513, where Elomo is lowest occupied molecular energy, DM is dipole moment, PMIZ is principal moment of inertia Z, PSA is polar surface area, and SD is sum of degrees. It provides a good way for us to obtain EC50₋24 h from EC50₋30 min, because the later is far easier to observe than the former.