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More and more studies have confirmed the importance of polarization effects in hydrogen bonding interactions in protein folding simulations. In this paper, a recently developed charge update scheme termed polarized structure-specific backbone charge (PSBC) model was applied to the folding of 10-residue chignolin. A comparison between simulations performed using PSBC and a nonpolarizable (AMBER99SB) force field demonstrably showed the importance of the electrostatic polarization effect in the folding of the short β-hairpin peptide by a series of analyses such as DSSP, free-energy landscape, hydrogen bond occupancy, and melting curve. The PSBC model was further validated by folding two other chignolin variants. [ABSTRACT FROM AUTHOR]

Depression severely impairs the health of people all over the world. Cognitive dysfunction due to depression has resulted in a severe economic burden to family and society induced by the reduction of social functioning of patients. Norepinephrine-dopamine reuptake inhibitors (NDRIs) targeted with the human norepinephrine transporter (hNET) and distributed with the human dopamine transporter (hDAT) simultaneously treat depression and improve cognitive function, and they effectively prevent sexual dysfunction and other side effects. Because many patients continue to poorly respond to NDRIs, it is urgent to discover novel NDRI antidepressants that do not interfere with cognitive function. The aim of this work was to selectively identify novel NDRI candidates acting against hNET and hDAT from large compound libraries by a comprehensive strategy integrating support vector machine (SVM) models, ADMET, molecular docking, in vitro binding assays, molecular dynamics simulation, and binding energy calculation. First, 6522 compounds that do not inhibit the human serotonin transporter (hSERT) were obtained by SVM models of hNET, hDAT, and non-target hSERT with similarity analyses from compound libraries. ADMET and molecular docking were then used to identify compounds that could potently bind to the hNET and hDAT with satisfactory ADMET, and 4 compounds were successfully identified. According to their docking scores and ADMET information, 3719810 was advanced for profiling by in vitro assays as a novel NDRI lead compound due to its strongest druggability and balancing activities. Encouragingly, 3719810 performed comparative activities on two targets, with Ki values of 7.32 μM for hNET and 5.23 μM for hDAT. To obtain candidates with additional activities and balance the activities of 2 targets, 5 analogs were optimized, and 2 novel scaffold compounds were successively designed. By assessment of molecular docking, molecular dynamics simulations, and binding energy calculations, 5 compounds were validated as NDRI candidates with high activities, and 4 of them performed acceptable balancing activities acting on hNET and hDAT. This work supplied promising novel NDRIs for treatment of depression with cognitive dysfunction or other related neurodegenerative disorders, and also provided a strategy for highly efficient and cost-effective identification of inhibitors for dual targets with homologous non-targets. [ABSTRACT FROM AUTHOR]

The unstable electrode–electrolyte interphase, poor rate capability, and severe lattice oxygen release of Li-rich layer oxides (LRNCM) severely limit their commercial application. Herein, an ultrathin Li2SiO3 protective layer with super toughness and functionality is uniformly constructed on the surface of LRNCM by atom layer deposition (ALD), which can not only suppress the side reactions of the electrode–electrolyte but also effectively alleviate the fragmentation of secondary particles (caused by the lattice stress), eventually leading to a huge improvement in structural and electrochemical stability, especially under harsh test conditions (high voltage or high temperature). Benefiting from these functionalized effects, the LRNCM electrode coated with 10 ALD cycles exhibits higher electrochemical stability at 60 °C, where its capacity retention rate still remains at 86.1% at 1 C after 100 cycles (vs. only 26% for bare LRNCM), and its rate capacity can also reach 188.7 mA h g−1 at 5 C. Hence, this work provides a significant pathway in overcoming capacity decay and electrode/electrolyte interface deterioration of LRNCM cathodes under extreme environments to broaden their application scenarios. [ABSTRACT FROM AUTHOR]

The physical properties and potential applications of two-dimensional (2D) materials can be effectively modulated and enriched by constructing van der Waals heterostructures (VDWHs) with two or more 2D monolayer materials. In this work, by using first-principles calculations based on density functional theory (DFT), we have systematically investigated the structural, electronic and optical properties of four α-Se-based VDWHs, that is, α-Se/Ca(OH)2, α-Se/GaSe, α-Se/h-BN and α-Se/MoS2 VDWHs. The results show that both the band alignment and band gap of these four VDWHs can be effectively modulated by interlayer coupling, biaxial strain and an external electric field. Compared with interlayer coupling and biaxial strain, the external electric field can modulate the electronic properties of these VDWHs more significantly, which makes them exhibit more rich electronic properties. Interestingly, the optical property calculations revealed that both α-Se and the four α-Se-based VDWHs have intrinsic hyperbolic properties. In addition, compared with the individual components, the optical absorption of these four VDWHs in the visible and ultraviolet light regions is significantly enhanced. These results enrich the properties of selenene and selenene-based VDWHs and extend their potential applications in electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Aqueous Zn–Ag batteries are promising candidates for the energy supply of stretchable and wearable electronics due to their stable voltage output and high energy density. However, due to the weak particle-to-particle connection and the easily falling-off nature of nano-/micro-size Ag powder, the manufacturing of stretchable high-performance Zn–Ag batteries remains challenging. Herein, we report a novel one-pot self-assembled Ag nanowire (AgNW) aerogel cathode with ultra-high electric conductivity (>7 × 105 S m−1, much higher than that of most current collectors), and thereby construct an intrinsically 500% super-stretchable Zn–Ag battery. The multi-directional growth and self-assembly of AgNWs are enabled in one facile polyol reaction, as such AgNW aerogel is produced conveniently without traditional pre-synthesis of AgNW monomers and subsequent high-temperature sintering. The as-fabricated Zn–Ag battery delivers a high energy density of 3.15 mW h cm−2 and a power density of 6.84 mW cm−2 with stable voltage and capacity output as well as excellent mechanical durability under heavy deformation, benefiting from the abundant electron-transport paths of AgNWs. With all these findings, this work will facilitate the application of stretchable energy storage/conversion systems, and the proposed ultra-high electrically conductive AgNW aerogel can also be a potential electrode or carrier with excellent performance and stability for stretchable and wearable electronics. [ABSTRACT FROM AUTHOR]

Positive allosteric modulators (PAMs) of human metabotropic glutamate receptor 2 (hmGlu2) are well-known in the treatment of psychiatric disorders for their higher selectivity and lower tolerance risk. A variety of PAMs have been reported over the last decade and two compounds were in Phase II clinical trials for schizophrenia and anxiety. These trials were discontinued on account of the unsatisfactory therapeutic efficacy, but PAMs were explored as novel treatments for addiction and epilepsy. Thus, it is still important to explore novel hmGlu2 PAMs in the near future. Nowadays, the challenges in optimizing drug potency and improving scaffold diversity for PAMs are the noncomprehensive character analyses of multiple scaffolds; the exploration of the binding modes of PAMs in the allosteric binding site have been proposed to reduce this difficulty. However, there has been no comprehensive research about the binding profiles of PAMs in the hmGlu2 receptor. To address this issue, this work explores the binding characters of eight PAMs representing five chemical series by multiple computational methods. As a result, the shared binding modes of the eight studied PAMs interacting with 15 residues in the allosteric binding site were defined. In addition, the reduced hydrophobicity with low electronegativity of R1, increased hydrophobicity with low negative electron density of R2 and the electronegativity of the linker were identified as indicators that regulate the affinity of PAMs. This finding agrees well with the physicochemical properties of reported multiple series PAMs. This comprehensive work sheds additional light on the binding mechanism and physicochemical regularity underlining PAMs affinity and could be further utilized as a structural and energetic blueprint for discovering and assessing novel PAMs for hmGlu2. [ABSTRACT FROM AUTHOR]

Stable high flux is a big challenge for oil/water separation membranes due to the adhesivity and spreadability of oil droplets. Membranes with hydrophilic modification usually have high basic flux, but suffer from a serious flux decline. Membranes with synergic hydrophilic and low-surface-energy (LSE) modification show a remarkably relieved flux decline, but at the expense of low basic flux. The LSE domains on membrane surfaces promote oil fouling release but hinder water permeation. In order to relieve the adverse side effects of LSE domains, this study focuses on the distribution of hydrophilic and LSE domains on membrane surfaces. Membranes with a fluorine island structure are prepared, in which LSE domains are discrete in sub-microscaled distribution, while hydrophilic domains are consecutive in a wide area. The diameters of oil droplets are much larger than those of water molecules; therefore, water molecules quickly permeate at consecutive hydrophilic domains, and oil droplets are still released by discrete LSE domains. The stable flux of the membranes is improved from 280 to 770 Lm−2 h−1 bar−1 just by the manipulation of domain distribution. [ABSTRACT FROM AUTHOR]

The first example of intramolecular ring-opening and reconstruction of cyclobutanone oxime esters via selective C–C bond cleavage leading to the synthesis of 3,4-dihydronaphthalene-2-carbonitriles in the presence of a cheap copper catalyst has been reported. The protocol is distinguished by mild and safe reaction conditions that exclude ligands, oxidants, bases, toxic cyanide salts and tolerates a wide scope of cyclobutanones without compromising their efficiency and scalability. The alternative visible-light-driven photoredox process for this coupling reaction was also uncovered. [ABSTRACT FROM AUTHOR]

Chitosan/poly(ethylene oxide)/permutit (CS/PEO/PT) composite nanofibers were prepared via electrospinning and their potential application in the removal of hexavalent chromium (Cr(vi)) from aqueous solutions was studied in detail. SEM results showed that the nanofibers were homogeneous and bead-free. XRD and DSC results demonstrated that there were strong interactions among CS, PEO and PT. The solubility test showed that the CS/PEO/PT composite membrane had excellent durability in water. The CS/PEO/PT-1% nanofibers exhibited the best adsorption performance for Cr(vi) ions in acidic solution (pH = 3) and at a low Cr(vi) concentration of 50 mg L−1. The maximum adsorption capacity reached 208 mg g−1. The adsorption kinetics and equilibrium data were well described by pseudo-second-order kinetic and Langmuir isotherm models, respectively. According to the results of FTIR and XPS analyses, protonation, ion exchange, electrostatic interactions and redox reactions were involved in the adsorption process. All the results indicated that the electrospun CS/PEO/PT nanofibers could be used as promising absorbents for the removal of Cr(vi). [ABSTRACT FROM AUTHOR]

Amitifadine, the only drug ever clinically tested in Phase 3 for treating depression, is a triple reuptake inhibitor (TRI) that simultaneously interacts with human monoamine transporters (MATs) including hSERT, hNET and hDAT. This novel multi-target strategy improves drug efficacy and reduces the toxic side effects of drugs. However, the binding modes accounting for amitifadine's polypharmacological mode of action are still elusive, and extensive exploration of the amitifadine–target interactions between amitifadine and MATs is urgently needed. In this study, a total of 0.63 μs molecular dynamics (MD) simulations with an explicit solvent as well as endpoint binding free energy (BFE) calculation were carried out. MD simulation results identified a shared binding mode involving eleven key residues at the S1 site of MATs for the binding of amitifadine, and the results of the BFE calculations were in good agreement with experimental reports. Moreover, by analyzing the per-residue energy contribution variation at the S1 site of three MATs and additional cross-mutagenesis simulations, the variation in the inhibition ratio of amitifadine between hSERT and two other MATs was discovered to mainly come from non-conserved residues (Y95, I172 and T439 in hNET and Y95, I172, A169 and T439 in hDAT). As the rational inhibition ratio of multi-target drugs among various therapeutic targets was found to be the key to their safety and tolerance, the findings of this study may further facilitate the rational design of more potent but less toxic multi-target antidepressant drugs. [ABSTRACT FROM AUTHOR]

In order to efficiently separate oil/water emulsions and enhance antifouling properties, a core–shell fiber-constructed pH-responsive nanofibrous hydrogel membrane (NHM) was successfully fabricated by a uniaxial electrospinning method. A simple thermal treatment stabilized the core–shell structure and enhanced the tensile stress of the NHMs. When immersed in water, the nanofibrous membrane exhibited a change to a transparent hydrogel membrane. The as-prepared NHMs possess superhydrophilic and underwater superoleophobic properties and can effectively separate various oil/water emulsions in acid, neutral or alkali environments, driven solely by gravity. Interestingly, the pH-responsive properties of the NHMs caused changes in the micromorphology of the nanofibers and the pore sizes of the membranes, which had great influences on the permeating flux (varying from 17 L m−2 h−1 to 1019 L m−2 h−1); moreover, there were no effects on separation performance. Due to their high flux, high separation efficiency (＞99%) and excellent recyclability (TOC ＜ 32 ppm after each cycle), these NHMs possess great potential for oily wastewater treatment and resource recycling. [ABSTRACT FROM AUTHOR]

Organic and organometallic molecules, which change their luminescence properties through a mechanical stimulus, such as emission wavelength and quantum yield, are called as mechanochromic or piezochromic materials. These functional molecules may be used as smart materials in the field of luminescent switches, mechanosensors, security papers, data storage, biological and healthcare applications. These materials are classified into two types, fluorescent and phosphorescent molecules. In this review, the recent progress in the phosphorescent mechanochromic materials, including pure organic molecules and metal complexes is highlighted. Their luminescence behaviors under mechanical force stimuli are shown and some critical concepts of molecular design for mechanoresponsive phosphorescent materials are also presented. [ABSTRACT FROM AUTHOR]

Nonplanar D–A phenothiazine derivative (PBA), in which phenothiazine and formylphenyl groups act as donor and acceptor, respectively, was designed and synthesized. The PBA emitted weak fluorescence in a solution, and its crystals exhibited weak blue-green emission with a luminescence efficiency of 7.5% under UV light irradiation owing to the lowest singlet (S1) of n–π* and the presence of intersystem crossing from S1 to T1. A grinding crystal provided a powder with strong yellow-green photoluminescence, whose luminescence efficiency increased by a factor of more than 6 after a mechanical force produced an enhanced TADF and an S1 of π–π*. [ABSTRACT FROM AUTHOR]

Antidepressants selectively inhibiting serotonin reuptake (SSRIs) represent a highly effective drug class, and novel therapeutic strategies were proposed to improve SSRIs' drug efficacy. The knowledge of the inhibitory mechanism of FDA approved SSRIs could provide great insights and act as important starting points to discover privileged drug scaffolds with improved efficacy. However, the structure of human serotonin transporter (hSERT) is yet to be determined and the inhibitory mechanism underlying SSRIs still needs to be further explored. In this study, the inhibitory mechanism of 4 approved SSRIs treating major depression (fluoxetine, sertraline, paroxetine and escitalopram) was identified by integrating multiple computational methods. Firstly, a recently published template with high sequence identity was adopted for the first time to generate hSERT's homology model. Then, docking poses of 4 SSRIs were used as the initial conformation for molecular dynamics (MD) simulation followed by MM/GBSA binding free energy calculation and per-residue free energy decomposition. Finally, the binding mode shared by the 4 studied SSRIs was identified by hierarchically clustering per-residue free energies. The identified binding mode was composed of collective interactions between 3 chemical groups in SSRIs and 11 hot spot residues in hSERT. 6 out of these 11 were validated by previous mutagenesis studies or pharmacophore models, and the remaining 5 (Ala169, Ala173, Thr439, Gly442 and Leu443) found in this work were not yet been identified as common determinants of all the 4 studied SSRIs in binding hSERT. Moreover, changes in SSRIs' binding induced by mutation on hot spot residues were further explored, and 3 mechanisms underlining their drug sensitivity were summarized. In summary, the identified binding mode provided important insights into the inhibitory mechanism of approved SSRIs treating major depression, which could be further utilized as a framework for assessing and discovering novel lead scaffolds. [ABSTRACT FROM AUTHOR]

Two new benzothizole modified carbazole derivatives (CBT and TCBT) were synthesized. It was found that TCBT with a tert-butyl moiety could gel cyclohexane, cyclopentanol and octane/cyclohexane (v/v = 2/1) under ultrasound stimulus, but CBT without a tert-butyl group failed to form an organogel in the selected solvents, revealing that tert-butyl played an important role in gel formation. X-ray diffraction patterns of xerogels indicated that TCBT molecules self-assembled into a lamellar structure in the gel state. In particular, xerogel-based films of TCBT emitted strong blue light and could be used as fluorescent sensory materials to detect acid vapors of TFA, HCl, HNO3, formic acid and acetic acid with high performance on account of the good adsorption and diffusion of analytes in 3D networks consisting lots of nanofibers as well as the efficient exciton migration in nanofibers. It suggested that the organogelation of π-gelators was a facile way to generate efficient chemosensors. [ABSTRACT FROM AUTHOR]

Hydrogen bonds could help two compounds (C12Ph and SP) with weak emission to produce strong fluorescent complexes and give them the capability to form gels in organic solvents. The complexes exhibited very weak emission in the sol state but emitted strong blue fluorescence with more than a 100-fold increase in emissive intensity after the sols changed into gels. The results from UV-vis absorption, circular dichroism and FT-IR spectral observations suggest that gelation induces the formation of J-aggregates. The fluorescence spectra imply that J-aggregates are responsible for the enhanced emission during gelation. Moreover, a small amount of SP, for example 10% by mole, could help C12Ph to construct three-dimensional fibrous networks and prevent the solvent from flowing. More importantly, a two-component gel film could be used as a sensor to quantitatively detect and discriminate between aliphatic and aromatic organic amine vapors. Aromatic amine vapors might quench the fluorescence of gel film and fluorescence would recover after the quenched film was exposed to air, suggesting a reversible sensing behaviour. On the other hand, although the strong blue emission disappeared after the gel film was exposed to aliphatic amine vapour, blue fluorescence was not restored because the hydrogen-bonded complex was destroyed. [ABSTRACT FROM AUTHOR]

4-(Carbazol-9-yl)benzaldehyde could emit yellow RTP, which could last for 3 s because of efficient intersystem crossing. Moreover, multicolor luminescent switches could be realized by simply applying a mechanical force stimulus. [ABSTRACT FROM AUTHOR]

Intense scientific efforts have been focused on the exploration of the unusual physical and chemical properties of colloidal nanoparticles (NPs). Here, surfactant-free ablated bismuth colloidal species showing distinctive advantages of high reactivity and reducibility were generated by laser-ablating metal Bi in deionized water. They can further react with water molecules and display self-assembly behaviour to form Bi(OH)3 nanowires at ambient condition. Interestingly, under aging at 60 °C or light irradiation, Bi-based colloids will tend to react and self-assemble into phases of Bi2O3 and Bi2O4 nanocrystals. Furthermore, various bismuth-containing compounds, such as bismuth oxyhalides (BiOX, X = Cl, Br, I), Ag/Au/Pt-modified BiOCl, BiVO4, and Bi2WO6 semiconductors were also successfully produced through the reaction of ablated bismuth colloidal species with corresponding chemical reagents or with ablated V and W colloidal species. These synthetic strategies proved that LAL-induced colloidal species are capable of serving as unique chemical precursors. The relatively slow, dynamic species-by-species reaction greatly favours controllable growth and tunable nanostructure compared with the conventional rapid ion-by-ion reaction. Importantly, this growth route provides more underlying insights regarding the growth and assembly mechanisms of nanocrystals without influence from additional chemical ions or surfactants. [ABSTRACT FROM AUTHOR]

Quantum-sized SnO2 nanocrystals can be well dispersed on reduced graphene oxide (rGO) nanosheets through a convenient one-pot in situ reduction route without using any other chemical reagent or source. Highly reactive metastable tin oxide (SnOx) nanoparticles (NPs) were used as reducing agents and composite precursors derived by the laser ablation in liquid (LAL) technique. Moreover, the growth and phase transition of LAL-induced SnOx NPs and graphene oxide (GO) were examined by optical absorption, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy. Highly dispersed SnOx NPs can also prevent rGO from being restacked into a multilayer structure during GO reduction. Given the good electron transfer ability and unsaturated dangling bonds of rGO, as well as the ample electrocatalytic active sites of quantum-sized SnO2 NPs on unfolded rGO sheets, the fabricated SnO2–rGO nanocomposite exhibited excellent performance in the non-enzymatic electrochemical detection of glucose molecules. The use of LAL-induced reactive NPs for in situ GO reduction is also expected to be a universal and environmentally friendly approach for the formation of various rGO-based nanocomposites. [ABSTRACT FROM AUTHOR]

The sequence-specific detection of DNA hybridization has attracted considerable interest in numerous fields. Although traditional DNA biosensors have been widely explored due to their high sensitivity, it is still challenging to develop a low-cost, portable, disposable, fast, and easy-to-use DNA detection method for public use at home or in the field. To address these challenges, herein, we report a novel microfluidic photoelectrochemical (PEC) paper-based analytical platform, integrated with an internal chemiluminescent light source, a novel paper supercapacitor (PS) amplifier, and a terminal digital multi-meter (DMM) detector, for sensitive DNA detection using a graphene-modified porous Au-paper electrode as the working electrode to obtain enhanced PEC responses. The quantification mechanism of this strategy is based on the charging of this PS, which was constructed on a paper-based analytical platform through a simple “drawing and soaking” method, by the generated photocurrent. After a fixed period, the PS was automatically shorted under the control of a novel built-in fluidic delay-switch to output an instantaneously amplified current, which could be sensitively detected by the DMM. At optimal conditions, this paper-based analytical platform can detect DNA at concentrations at femtomolar level. This approach also shows excellent specificity toward single nucleotide mismatches. [ABSTRACT FROM AUTHOR]

In this work, microfluidic paper-based analytical device (μ-PAD) was applied in a photoelectrochemical (PEC) method and thus a truly low-cost, simple, portable, and disposable microfluidic PEC origami device (μ-PECOD) was demonstrated. The molecular imprinting technique was introduced into microfluidic paper-based analytical devices (μ-PADs) through electropolymerization of molecular imprinted polyaniline (MPANI) in a novel Au nanoparticle (AuNP)-modified paper working electrode (Au-PWE). This is fabricated through the growth of an AuNP layer on the surfaces of cellulose fibers in the PWE. Under visible light irradiation, MPANI can generate the photoelectric transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), delivering the excited electrons to the AuNPs, and then to the carbon working electrode. Simultaneously, it is believed that a positively charged hole of MPANI that took part in the oxidation process was consumed by ascorbic acid (AA) to promote the amplifying photocurrent response. On the basis of this novel MPANI-Au-PWE and the principle of origami, a microfluidic molecular imprinted polymer (MIP)-based photoelectrochemical analytical origami device (μ-MPECOD), comprised of an auxiliary tab and a sample tab, is developed for the detection of heptachlor in the linear range from 0.03 nmol L−1 to 10.0 nmol L−1 with a low detection limit of 8.0 pmol L−1. The selectivity, reproducibility, and stability of this μ-MPECOD are investigated. This μ-MPECOD would provide a new platform for high-throughput, sensitive, specific, and multiplex assay in public health, environmental monitoring, and the developing world. [ABSTRACT FROM AUTHOR]

A molecular imprinted polymer thin film for photoelectrochemical (PEC) sensing of chlorpyrifos molecules was first constructed by electropolymerizing the o-phenylenediamine (o-PD) monomer and chlorpyrifos template molecule on gold nanoparticles-modified titanium dioxide nanotubes. The resulting PEC sensors were characterized by scanning electron microscopy, ultraviolet (UV)-vis spectra and electrochemical impedance spectra. Clearly, the imprinted film showed high selectivity to chlorpyrifos in our case. Under visible light irradiation, poly(o-phenylenediamine) (PoPD) can generate the photoelectric transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), delivering the excited electrons to the AuNPs, and then to the conduction band (CB) of the titanium dioxide nanotubes (TiO2 NTs). Simultaneously, it is believed that a positively charged hole (h+) of PoPD that took part in the oxidation process was consumed to promote the amplification of photocurrent response. Under the optimal experimental conditions, the photocurrents were proportional to the concentrations of chlorpyrifos ranging from 0.05 to 10 μmol L−1 with the detection limit of 0.96 nmol L−1. The PEC sensor had an excellent specificity and could be successfully applied to the detection of reduced chlorpyrifos in green vegetables, indicating a promising application in PEC sensing. [ABSTRACT FROM AUTHOR]

An ultrasensitive photoelectrochemical (PEC) immunoassay was introduced into microfluidic paper-based analytical devices (μ-PADs) based on a multiple electron transfer system for the first time, which was constructed using narrow-band-gap semiconductor nanoparticles (NPs), wide-band-gap semiconductor NPs, and an electron-accepting medium. [ABSTRACT FROM AUTHOR]

A photoelectrochemical immunoassay was introduced for the first time into a microfluidic paper-based analytical device equipped with a paper supercapacitor for low-cost, simple, portable, and disposable point-of-care testing, based on a chemiluminescence light source and a digital multi-meter. [ABSTRACT FROM AUTHOR]

In this study, molecular dynamics simulations were used to systematically explore the reason why BH3-only protein BAD binds to anti-apoptotic protein BCL- x L but not to MCL-1 to give more theoretical hints for the design of BAD mimetic inhibitors for the dual-targeting of BCL- x L and MCL-1. Starting with the difference in residue-based binding energy contributions, a series of analyses were conducted to identify the hotspot residues in MCL-1 that significantly affect the interaction with BAD. Among them, the insertion of the T residue in the loop between α4 and α5 domains of MCL-1 is considered to be the main cause of BAD selective binding. The inserted T residue reduces the stability of the loop and weakens the hydrogen bond interactions that originally bound E19 of BAD in BCL- x L/BAD, and the freed E19 severely interferes with the salt bridge between D16 and Arg53 by electrostatic repulsion. This salt-bridge is believed to be critical for maintaining the binding between BCL- x L and BAD. By clarifying the reasons for differential binding, we can more specifically optimize the BAD sequence to target both BCL- x L and MCL-1.

A label-free photoelectrochemical (PEC) immunosensor is introduced into a microfluidic paper-based analytical device using tetra-carboxyl naphthalocyanine zinc (ZnNc-COOH) sensitized ZnO nanorods (NRs) as photoactive materials. Firstly, ZnO NRs are grown on a Au nanoparticles modified paper working electrode (Au-PWE) via a simple and low temperature hydrothermal method. With the aid of 4-aminothiophenol (PATP), ZnNc-COOH can be attached onto the ZnO NRs surface due to the formation of a strong bond (Zn-S) between the thiol end of the PATP molecule and the ZnO NRs, and the remaining amino group forms an acrylamide bond with ZnNc-COOH. To perform the immunoassay, carcinoembryonic antigen (CEA) antibodies are conjugated onto the ZnNc-COOH sensitized electrode by using the classic 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) coupling reactions between COOH groups on the surfaces of the ZnNc-COOH and NH 2 groups of the antibodies. The concentrations of CEA are measured through the decrease in photocurrent intensity resulting from the increase in steric hindrance due to the formation of the immunocomplex. Under the optimized experimental conditions, the paper-based PEC immunosensor exhibits excellent analytical performance for detection of CEA, ranging from 0.005-100 ng mL -1 with a low detection limit of 1.6 pg mL -1 . The PEC immunosensor shows high sensitivity, stability, and reproducibility. The proposed method provides a new strategy for a sensitive, low-cost, specific, and multiplex assay.

Quantum-sized SnO2 nanocrystals can be well dispersed on reduced graphene oxide (rGO) nanosheets through a convenient one-pot in situ reduction route without using any other chemical reagent or source. Highly reactive metastable tin oxide (SnO(x)) nanoparticles (NPs) were used as reducing agents and composite precursors derived by the laser ablation in liquid (LAL) technique. Moreover, the growth and phase transition of LAL-induced SnO(x) NPs and graphene oxide (GO) were examined by optical absorption, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy. Highly dispersed SnO(x) NPs can also prevent rGO from being restacked into a multilayer structure during GO reduction. Given the good electron transfer ability and unsaturated dangling bonds of rGO, as well as the ample electrocatalytic active sites of quantum-sized SnO2 NPs on unfolded rGO sheets, the fabricated SnO2-rGO nanocomposite exhibited excellent performance in the non-enzymatic electrochemical detection of glucose molecules. The use of LAL-induced reactive NPs for in situ GO reduction is also expected to be a universal and environmentally friendly approach for the formation of various rGO-based nanocomposites.

A three-dimensional microfluidic origami glucose-air immuno-biofuel cell has been successfully demonstrated for the first time to implement self-powered, sensitive, and low-cost sandwich immunoassay for cancer markers based on the signal amplifications of a porous Au-paper electrode and Au nanoparticles attached to carbon nanotubes.

A molecular imprinted polymer thin film for photoelectrochemical (PEC) sensing of chlorpyrifos molecules was first constructed by electropolymerizing the o-phenylenediamine (o-PD) monomer and chlorpyrifos template molecule on gold nanoparticles-modified titanium dioxide nanotubes. The resulting PEC sensors were characterized by scanning electron microscopy, ultraviolet (UV)-vis spectra and electrochemical impedance spectra. Clearly, the imprinted film showed high selectivity to chlorpyrifos in our case. Under visible light irradiation, poly(o-phenylenediamine) (PoPD) can generate the photoelectric transition from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), delivering the excited electrons to the AuNPs, and then to the conduction band (CB) of the titanium dioxide nanotubes (TiO(2) NTs). Simultaneously, it is believed that a positively charged hole (h(+)) of PoPD that took part in the oxidation process was consumed to promote the amplification of photocurrent response. Under the optimal experimental conditions, the photocurrents were proportional to the concentrations of chlorpyrifos ranging from 0.05 to 10 μmol L(-1) with the detection limit of 0.96 nmol L(-1). The PEC sensor had an excellent specificity and could be successfully applied to the detection of reduced chlorpyrifos in green vegetables, indicating a promising application in PEC sensing.