In vivo effects of low dose prenatal bisphenol A exposure on adiposity in male and female ICR offspring.

BACKGROUND: Bisphenol A (BPA) is known to exhibit endocrine disrupting activities and is associated with adiposity. We examined the obesogenic effect of prenatal BPA exposure in the present study. METHODS: Pregnant ICR mice were exposed to vehicle or BPA via the drinking water at a dose of 0.5 µg/kg·d throughout the gestation. Obesity-related indexes were investigated in the 12-wk-old offspring. Primary mouse embryonic fibroblasts (MEFs) collected from treated embryos were used to test effects of BPA on adipocyte differentiation. RESULTS: Offspring presented a significantly higher rate of weight gain than the control, with impaired insulin sensitivity and increased adipocyte size. Differentiation of MEFs from BPA-treated mice showed a higher propensity for the adipocyte commitment as well as up-regulation of genes enriched in lipid biosynthesis. TGF-ß signaling pathway was found to modulate obesogenic effect of BPA in MEF model, but estrogen signaling pathway had no effect. CONCLUSIONS: The present study provides strong evidence of the association between prenatal exposure to low dose of BPA and a significant increase in body weight in the offspring mice with a critical role played by TGF-ß signaling pathway. The potential interactions modulating the binding of BPA and TGF-ß that activate its obesogenic effects need to be examined.

Tandem Förster resonance energy transfer induced visual ratiometric fluorescence sensing of tetracyclines based on zeolitic imidazolate framework-8 incorporated with carbon dots and safranine T.

Developing new methods for efficiently detecting tetracycline antibiotics in water has gained much importance. In this work, zeolitic imidazolate framework-8 (ZIF-8) was used as a host to encapsulate carbon dots (CDs) and safranine T (ST) during its self-assembly process to synthesize CDs/ST@ZIF-8, which was then applied as the dual-emissive probe for detecting tetracycline antibiotics. Benefiting from the confinement effects of ZIF-8 and its fluorescence enhancement effects toward tetracycline (TC), a unique tandem Förster resonance energy transfer (FRET) system from CDs to TC and then to ST could be established, with a low limit of detection of 46 nM and excellent selectivity. More importantly, as compared to the CDs/ST system without tandem FRET, the sensitivity of the CDs/ST@ZIF-8 toward TC increased ∼69-fold, and naked eye recognition could also be achieved. Furthermore, by analyzing the R, G, and B values of photos containing different concentrations of tetracycline with the help of a mobile phone and correlating them with the concentration of tetracycline, we can perform the on-site detection of tetracycline, which is convenient, fast, and accurate. This study shows that new insight can be gained for the rational design and application of ratiometric fluorescence sensors based on tandem Förster resonance energy transfer in metal-organic framework materials.

Corrigendum to "Cobalt metal-organic framework modified carbon cloth/paper hybrid electrochemical button-sensor for nonenzymatic glucose diagnostics" [Sens. Actuators B Chem. 329 (2021) 129205].

[This corrects the article DOI: 10.1016/j.snb.2020.129205.].

Self-Assembled Multivalent Ag-SR Coordination Polymers with Phosphatase-Like Activity.

We show herein the phosphatase-like catalytic activity of coordination polymers obtained after adding Ag+ -ions to thiols bearing hydrophobic alkyl chains terminated with a 1,4,7-triazacyclononane (TACN) group. The subsequent addition of Zn2+ -ions to the self-assembled polymers resulted in the formation of multivalent metal coordination polymers capable of catalysing the transphosphorylation of an RNA-model compound (2-hydroxypropyl-4-nitrophenyl phosphate, HPNPP) with high reactivity. Analysis of a series of metal ions showed that the highest catalytic activity was obtained when Ag+ -ions were used as the first metal ions to construct the backbone of the coordination polymer through interaction with the -SH group followed by Zn2+ -ions as the second metal ions complexed by the TACN-macrocycle. Furthermore, it was demonstrated that the catalytic activity could be modulated by changing the length of the hydrophobic alkyl chain.

Chromatin-enriched RNAs mark active and repressive cis-regulation: An analysis of nuclear RNA-seq.

Long noncoding RNAs (lncRNAs) localize in the cell nucleus and influence gene expression through a variety of molecular mechanisms. Chromatin-enriched RNAs (cheRNAs) are a unique class of lncRNAs that are tightly bound to chromatin and putatively function to locally cis-activate gene transcription. CheRNAs can be identified by biochemical fractionation of nuclear RNA followed by RNA sequencing, but until now, a rigorous analytic pipeline for nuclear RNA-seq has been lacking. In this study, we survey four computational strategies for nuclear RNA-seq data analysis and develop a new pipeline, Tuxedo-ch, which outperforms other approaches. Tuxedo-ch assembles a more complete transcriptome and identifies cheRNA with higher accuracy than other approaches. We used Tuxedo-ch to analyze benchmark datasets of K562 cells and further characterize the genomic features of intergenic cheRNA (icheRNA) and their similarity to enhancer RNAs (eRNAs). We quantify the transcriptional correlation of icheRNA and adjacent genes and show that icheRNA is more positively associated with neighboring gene expression than eRNA or cap analysis of gene expression (CAGE) signals. We also explore two novel genomic associations of cheRNA, which indicate that cheRNAs may function to promote or repress gene expression in a context-dependent manner. IcheRNA loci with significant levels of H3K9me3 modifications are associated with active enhancers, consistent with the hypothesis that enhancers are derived from ancient mobile elements. In contrast, antisense cheRNA (as-cheRNA) may play a role in local gene repression, possibly through local RNA:DNA:DNA triple-helix formation.

Cobalt metal-organic framework modified carbon cloth/paper hybrid electrochemical button-sensor for nonenzymatic glucose diagnostics.

In the growing pandemic, family healthcare is widely concerned with the increase of medical self-diagnosis away from the hospital. A cobalt metal-organic framework modified carbon cloth/paper (Co-MOF/CC/Paper) hybrid button-sensor was developed as a portable, robust, and user-friendly electrochemical analytical chip for nonenzymatic quantitative detection of glucose. Highly integrated electrochemical analytical chip was successfully fabricated with a flexible Co-MOF/CC sensing interface, effectively increasing the specific area and catalytic sites than the traditional plane electrode. Based on the button-sensor, rapid quantitative detection of glucose was achieved in multiple complex bio-matrixes, such as serum, urine, and saliva, with desired selectivity, stability, and durability. With the advantages of low cost, high environment tolerance, ease of production, our nanozyme-based electrochemical analytical chip achieved reliable nonenzymatic electrocatalysis, has great potential for the application of rapid on-site analysis in personalized diagnostic and disease prevention.

MoS2 quantum dots as a specific fluorescence sensor for selection of rutin and for temperature sensing.

A selective and sensitive method for detecting rutin using MoS2 quantum dots (QDs) as a fluorescent probe is reported in the paper, a one-step hydrothermal synthesis method was used to prepare MoS2 QDs. The synthesized MoS2 QDs had good stability and water solubility, and the fluorescence of MoS2 QDs was quenched by rutin due to the inner filter effect. There was a good linear relationship between the intensity of MoS2 QDs and rutin concentration ranging from 5.0 × 10-7 to 3.2 × 10-5 mol/L with a detection limit of 3.5 × 10-7 mol/L. MoS2 QDs showed temperature-dependent fluorescence that had an excellent linear relationship between 20 and 80°C. Therefore MoS2 QDs can be used as specific fluorescence sensors for selection of rutin and for temperature sensing.

Differential potential ratiometric sensing platform for enantiorecognition of chiral drugs.

A versatile, robust and efficient differential potential ratiometric sensing platform was developed for enantioselective recognition of dual chiral targets based on a composite membrane of molecularly imprinted polymers (MIPs) and reduced graphene oxide (rGO) modified glassy carbon electrode (GCE). The functional chitosan-based MIPs and rGO were compatibly immobilized on the GCE with high selectivity and efficient signal amplification. Moreover, via the systematic optimization of series conditions, a distinct potential difference (PD), reaching 135 mV, was obtained between the R-/S-prop based on the MIPs/rGO/GCE. In a controllable concentration range from 50 µM to 1000 µM, different ratios of R-/S-prop were linearly related to the peak potentials (Eps) in the racemic mixture. Using this low-cost reversible electrochemical platform, both Prop enantiomers were simultaneously identified with high repeatability and time-based stability. This novel semi-quantitative electrochemical sensing platform was established to rapidly quantify the ratio of S-/R-prop by Ep for the chiral drug recognition with great potential for practical applications in fields of pharmacological detection and clinical analysis.

Diverse applications of TMB-based sensing probes.

Extending the research on 3,3',5,5'-tetramethylbenzidine (TMB) and its derivatives in analytical chemistry is important, considering that TMB is widely used as an enzyme catalytic substrate. In this work, two TMB derivatives, TMBS and TMBB, were synthesized via a facile and one-step condensation reaction between the -NH2 group of TMB and the -CHO group of salicylaldehyde or benzaldehyde. Because at low pH the two Schiff base compounds can release TMB which can emit strong fluorescence, the probes could show dual-modal signal responses, fluorescence and UV-vis absorption, towards the pH. Practical applications of pH sensing in Chinese rice vinegar and lemon juice samples were successfully demonstrated. On the basis of these findings, a catalytic chromogenic reaction was developed to monitor the pH with the naked eye, too. Furthermore, considering the chemical equilibrium reaction between CO2 and H2O and that glucose oxidase (GOD) can catalyse the dehydrogenation and oxidation reaction of ß-d-glucose to produce gluconic acid, both of which can result in lowering the pH values of the two Schiff base systems, highly sensitive and selective dual-modal sensing systems for detecting CO2 and ß-d-glucose have also been successfully established. Therefore, the two synthesized TMB derivatives can demonstrate their robust application potential.

Sensitive detection of L-5-hydroxytryptophan based on molecularly imprinted polymers with graphene amplification.

A novel electrochemical sensor was presented for the determination of L-5-hydroxytryptophan (L-5-HTP) based on a graphene-chitosan molecularly imprinted film modified on the surface of glassy carbon electrode (GR-MIP/GCE). The morphology and composition of the imprinted film were observed in field emission scanning electron microscopy (FESEM), raman spectroscopy and fourier transform infrared (FTIR). The properties of the sensor were evaluated by electrochemical techniques. Under the optimal conditions, the peak currents of L-5-HIP were found to be linear in the concentration range of 0.05-7.0 µM, while the sensor also exhibited great features such as low detection limit of 6.0 nM (S/N = 3), superb selectivity against the structural analogues, good antidisturbance ability among coexisting components, excellent repeatability and stability. Moreover, the proposed method had been applied to the detection of L-5-HTP in human blood serum with a satisfactory recoveries ranging from 90.6% to 105.6%.

Graphene-quantum-dots-based ratiometric fluorescent probe for visual detection of copper ion.

A novel dual-photoluminescence probe for Cu(2+) has been developed, in which the graphene quantum dots with blue emission and CdTe QDs with yellow emission act as internal standard and probe, respectively. The photoluminescence probe exhibited selective sensing for Cu(2+) with a limit of detection (3SD/k) of 5.3 × 10(-8) M and showed its potential application in visual imaging. The results indicated that the constructed probe can be employed for sensing Cu(2+) by the naked eye, and also for monitoring intracellular Cu(2+).

Xanthine microsensor based on polypyrrole molecularly imprinted film modified carbon fiber microelectrodes.

A molecularly imprinted polymers (MIPs) microsensor was presented as a carbon fiber microelectrode (CFME) coating for specifically recognizing xanthine (Xan). The polymeric film was obtained based on the imprinted procedure of electropolymerization of pyrrole in the presence of the template molecule Xan by cyclic voltammetry, and template was removed by magnetic stirring. Under the optimum conditions, a satisfactory molecularly binding selectivity of Xan was obtained from the MIPs microsensor with an imprinting factor (IF) of 6.63 and a linear response to concentration in certain ranges. The ranges are from 4.0 × 10⁻6 to 6.0 × 10⁻5 M and from 8.0 × 10⁻5 to 2.0 × 10⁻³ M with a detection limit of 2.5 × 10⁻7 M. Meanwhile, good stability (relative standard deviation [RSD] = 3.2%, n = 10) and reproducibility (RSD = 2.0%, n = 10) were observed, and recoveries ranging from 96.9 to 102.5% were calculated when applied to Xan determination in real blood serum samples.

Aggregation emission of AuNCs induced by chitosan self-assembled multilayers and sensitive sensing for water content in ethanol.

AuNCs with chemical groups such as -NH2 and -COOH were synthesized using glutathione as the stabilizer and reducing agent. The aggregation emission of AuNCs in solution-induced self-assembled multilayers (SAMs) were first studied. Scanning electron microscopy and quartz crystal microbalance were used to characterize the morphology and aggregation process of AuNCs. Further AuNC SAMs were used for the solid-liquid interface sensing of water content in ethanol, and the sensitivity is obviously improved as compared with that in the pure solution phase. This aggregation emission induced by SAMs would have a good application prospect in analysis.

A urea electrochemical sensor based on molecularly imprinted chitosan film doping with CdS quantum dots.

An improved imprinted film-based electrochemical sensor for urea recognition was developed using CdS quantum dots (QDs) doped chitosan as the functional matrix. The microstructure and composition of the imprinted films depicted by scanning electron microscopy (SEM), attenuated total reflection infrared (ATR-IR), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS) indicated the fabricated feasibility of the nanoparticle doped films via in situ electrodeposition. Differential pulse voltammetric responses under the optimal fabrication conditions showed that the sensitivity of CdS QDs-MIP (molecularly imprinted polymer) electrochemical sensor was enhanced from the favorable electron transfer and magnified surface area of CdS QDs with a short adsorption equilibrium time (7 min), wide linear range (5.0 × 10(-12) to 4.0 × 10(-10) M and 5.0 × 10(-10) to 7.0 × 10(-8) M), and low detection limit (1.0 × 10(-12) M). Meanwhile, the fabricated sensor showed excellent specific recognition to template molecule among the structural similarities and coexistence substances. Furthermore, the proposed sensor was applied to determine the urea in human blood serum samples based on its good reproducibility and stability, and the acceptable recovery implied its feasibility for practical application.

Dual-emission quantum dots nanocomposites bearing an internal standard and visual detection for Hg2+.

A novel dual-fluorescence quantum dots (QD) nanocomposite with tuning emission wavelength and fluorescence intensity was synthesized, in which CdS and CdTe were the internal standard and probe, respectively. This nanocomposite exhibited good photobleaching and pH stability, and exhibited selective sensing for Hg(2+) with a detection limit (3SD/k) of 5.6 nM. Based on the blue background emitted by the internal standard CdS, a novel visual fluorescence detection method has been established, and can be used for the qualitative and semi-quantitative colorimetric analysis of Hg(2+).

Water-soluble long afterglow carbon dots/silica composites for dual-channel detection of alkaline phosphatase and multi-level information anti-counterfeiting.

Water-soluble carbon dots/silica (CDs/SiO2) composites with an ultra-long lifetime of 846.9 ms and an ultra-high afterglow quantum yield of 12.1% were successfully obtained by incorporating CDs into a SiO2 network. Within the aqueous solution, the SiO2 layer isolates CDs from the surrounding oxygen. Meanwhile, hydrogen bonds and covalent bonds are formed between the CDs and SiO2, and these bonds restrict the movement and vibration of the CDs. Accordingly, the non-radiative inactivation rate of the triplet excitons of the CDs is reduced, thereby enhancing the room-temperature phosphorescence of the CDs and triggering thermally activated delayed fluorescence. The multiple properties of the material effectively protect the CDs from the external environment, making CDs/SiO2 emit a long afterglow in the solid and liquid phases. The prepared CDs/SiO2 composites have exceptional stability against strong oxidants, acids, bases, and polar solvents. The composites were successfully used in the dual-optical mode detection of alkaline phosphatase, as an anti-counterfeiting ink, and in multi-level information anti-counterfeiting and encryption.

A novel ratiometric fluorescent probe for water content in ethanol and temperature sensing.

In this paper, two tetrahydo[5]helicene-based dyes (THH1 and THH2) were studied on their twist intramolecular charge transfer. And the water-soluble blue carbon dots (N-CDs) were synthesized. Considering that their different optical propeties, the ratiometric fluorescence probes N-CDs/THH1 and N-CDs/THH2 were constructed by mixing N-CDs and dyes simply. It was found that N-CDs/THH1 and N-CDs/THH2 could quickly and sensitively detect water content in ethanol, with linear range of 0.500-25.0 vol% and 0.500-30.0 vol%, respectively. What's more, through the actual sample test, it showed that the detection had good accuracy and precision. At the same time, it was found that two ratiometric probes could also be applied to the thermometry with good reversibility based on optical temperature sensors.

Synthesis, properties, and light-induced shape memory effect of multiblock polyesterurethanes containing biodegradable segments and pendant cinnamamide groups.

Novel multiblock polyesterurethanes containing crystalline hard and amorphous soft segments and pendant cinnamamide moieties were designed and synthesized via a two-step polyaddition reaction using N,N-bis(2-hydroxyethyl) cinnamamide (BHECA), biodegradable poly(l,l-lactide) (PLLA), and poly(ε-caprolactone) (PCL) diols as raw materials and hexamethylene diisocyanate (HDI) as coupling agent and characterized by (1)H NMR, FTIR, UV, DSC, tensile and photomechanical tests, and so on. The copolymers behaved as typical thermoplastic elastomers and showed satisfactory thermal and mechanical properties. They also exhibited light-induced shape memory effect (LSME) at room temperature on exposure to light stimuli. The pendant cinnamamide groups work as photoresponsive molecular switches and provide the polymer with LSME via reversible [2 + 2] cycloaddition cross-linking. The strain fixity (R(f)) increases with the content of BHECA and the strain recovery (R(r)) increases with the content of PLLA. The R(f) reaches 50% at a BHECA content of 20 wt % and the R(r) reaches >95% at PLLA content of 50 wt %.

A sensitive and regenerable biosensor for organophosphate pesticide based on self-assembled multilayer film with CdTe as fluorescence probe.

A fluorescence biosensor for organophosphorus pesticides was developed. A pH indicator, CdTe quantum dots, were used as an optical transducer of the inhibition of enzyme by analyte. Through the intervening agency of chitosan, the recognition elements (acetylcholinesterase and CdTe) were immobilized onto the surface of quartz by electrostatic attraction to form a self-assembled multilayer film. In the absence of pesticide, acetylcholine was biocatalytically hydrolysed to yield acetic acid and choline. The released acid resulted in pH decrease, which was sensed by the immobilized pH indicator (CdTe). In the presence of pesticide, the action of acetylcholine was reduced; the fluorescence intensity of the film changed and was related to the concentration of pesticide. This multilayer film could be used as the biosensor for monocrotophos, with a detection limit of 3.20 × 10(-8) mol/L; the sensitivity was 100 times higher than that of CdTe in aqueous solution. The sensor was easily regenerated, and had good stability and selectivity for organophosphorus pesticides.

Dual fluorescence self-assembled multilayers bearing a fluorescent internal standard for interfacial sensing.

A novel dual fluorescence film Quartz/PSS/AO/PSS/CS/CdTe sensor was constructed based on layer-layer electrostatic attraction using CdTe as a fluorescence probe. Acridine orange is shielded effectively by sodium poly(4-styrenesulfonate) and chitosan, thus its fluorescence intensity does not change in the presence of the analyte, thereby acting as a fluorescent internal standard providing a reference signal. The ratio of dual fluorescence intensities of the film sensor is not affected by the fluctuation of the external environment factors such as excitation intensity, detector voltage of photo multiplier tube and sensor position in the cell holder. Assays based on this dual fluorescence self-assembled multilayers sensor afforded an extremely high sensitivity for DNA with greatly accuracy.