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Tannery solid waste (TSW) contains 70–90% collagen by weight. The rapid extraction of collagen while preserving its original and unique triple-helical conformation has proved challenging. In this paper, an ionic liquid-synergistic dissolution and regeneration (IL-SDR) method was developed based on a TBAH/DMSO/H2O ternary (TDH) solvent for the rapid recovery of collagen from TSW under mild conditions. A solubility of 10.25% TSW and a collagen recovery yield of 51.2% were achieved in 30 minutes at room temperature. The original triplet helical conformation and the molecular weight of the collagen product were retained, confirmed via FT-IR, circular dichroism, and matrix-assisted laser desorption/ionization time-of-flight analysis. SEM was used to verify that dense and uniform pores could be formed within collagen by adjusting the DMSO content, and cytotoxicity and moisture retention tests demonstrated that the collagen produced via the IL-SDR process is comparable to natural collagen used in cosmetic and skincare applications. Moreover, the TDH solvent demonstrated excellent reproducibility across five cycles, achieving consistent solubility varying from 9.71% to 11.04%. EPR and 1H NMR showed that the OH– in TBAH induced the generation of DMSO˙ free radicals in the TDH solvent, and these radicals were indispensable for the dissolution of TSW. The DMSO content was positively correlated with the concentration of free radicals. A synergistic dissolution mechanism was proposed: DMSO˙ free radicals preferentially cleaved the terminal peptide chains, causing the collagen molecules to be exposed to DMSO. Subsequently, DMSO disrupted the original hydrogen bond network within the collagen molecules. Then, TBAH and DMSO formed hydrogen bonds with the collagen molecules, stabilizing the dissolved collagen and preventing the reformation of the hydrogen bond network between collagen molecules. This work provides an avenue for low-temperature and rapid dissolution of TSW, and reveals an in-depth, atypical dissolution mechanism for collagen-based materials during the IL-SDR process. [ABSTRACT FROM AUTHOR]

The constrained enzymatic activity and aggregation challenges encountered by small-sized nanozymes pose obstacles to their practical utility, necessitating a strategy to mitigate aggregation and boost enzymatic catalytic efficiency. In this work, a negatively charged Eu MOF was utilized as the encapsulation matrix, encapsulating the small-sized nanozymes FeNCDs into the Eu MOF to synthesize an FeNCDs@Eu MOF. The dispersibility of the encapsulated FeNCDs was increased, and owing to the negative charge of the FeNCDs@Eu MOF, electrostatic pre-concentration of the positively charged target molecule tetracycline (TC) was facilitated, thereby amplifying the enzymatic catalytic efficiency of the FeNCDs. The response of the FeNCDs to TC increased by nearly 6 times upon encapsulation. The TC detection limit (LOD) of the FeNCDs@Eu MOF-based sensor is as low as 11.63 nM. The incorporation of fluorescence detection expanded the linear range of the sensor, rendering it more suitable for practical sample detection. [ABSTRACT FROM AUTHOR]

Electrochemiluminescence nanoprobes with a core–shell–shell structure have been designed and applied for hyaluronidase detection. The nanoprobes can precipitate efficiently through target-regulation wettability for collection, and enrich near to the hydrophobic electrode surface through hydrophobic interaction to enhance the performance of the biosensor. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered MoS2 has good dispersion and adsorption properties, but being a narrow bandgap semiconductor limits its application in photoelectric sensing. In this study, a homogeneous photoelectrochemical sensor based on three-dimensional (3D) ZnO/Au/2D MoS2 is proposed for the ultrasensitive detection of tetracycline (TET). MoS2 is uniformly embedded on the 3D ZnO/Au surface by ordered self-assembly. The physical method of π–π interaction of MoS2 replaces the conventional use of chemically modifying aptamers on the electrode material surface. Under optimal conditions, this method has been successfully applied to the detection of TET in milk, honey, pig kidney and pork samples with reliable results. We believe that this study presents a method for the preparation of sensing carriers and target detection with great potential for application. [ABSTRACT FROM AUTHOR]

Nickel-doped iridium echinus-like nanosheets (NiIr-ENS) have a superior acidic oxygen evolution reaction (OER) activity with a TOF of 1.72 s−1 at an overpotential of 300 mV, 8.6-fold higher than that of IrO2. [ABSTRACT FROM AUTHOR]

A novel photoelectrochemical (PEC) sensor was constructed for the highly sensitive detection of reduced glutathione (GSH) based on the multiple catalytic properties of phosphotungstic acid (PTA). In this work, the catalytic properties of PTA were applied to PEC sensing for the first time and interpreted in detail. First, PTA as an electron acceptor can inhibit the complexation of photogenerated electron–hole pairs in p-Cu2O, thus significantly increasing the photogenerated current of p-type semiconductor material Cu2O. Secondly, when GSH is oxidized to oxidized glutathione (GSSG) by photogenerated holes on the photocathode, PTA is able to reduce GSSG to GSH by transferring protons, forming a redox cycle regeneration process of GSH. Finally, the relatively large amount of PTA in the background solution was able to pre-oxidize interfering substances such as L -cysteine and ascorbic acid, which improved the selectivity of the method. Under the optimal experimental conditions, the linear range of the PEC sensor response to GSH was 0.050–100 nmol L−1, with a detection limit as low as 0.017 nmol L−1 (S/N = 3), which can be applied to the detection of GSH content in cell lysate samples. [ABSTRACT FROM AUTHOR]

Optogenetics using light-sensitive proteins such as calcium transport channel rhodopsin (CatCh) opens up new possibilities for non-invasive remote manipulation of neural function. However, current optogenetic approaches for neurological disorder therapies rely on visible light excitation and are rarely applied to neurogenesis and nerve regeneration. Herein, we propose a new strategy for tissue engineering which combines optogenetic technology and biomimetic nerve scaffolds. Upconversion nanoparticles (UCNPs) were synthesized and integrated with oriented fibrillar PCL membranes with a collagen coating to establish neuro-matrix interfaces. Benefiting from the excellent bioactivity, oriented fibrillation and NIR-photoresponsivity, the CatCh-transfected PC12 cells on these interfaces exhibited enhanced cell elongation and neurite extension, as well as upregulated neurogenesis upon NIR excitation. Furthermore, a UCNP-integrated scaffold as an optogenetic actuator allowed NIR to penetrate dermal tissues to mediate neural activation, with an efficiency comparable to that of a 470 nm blue light. Compared with current visible light-excited optogenetics, our composite scaffold-mediated NIR stimulation addresses the problem of tissue penetration and will enable less-invasive neurofunctional manipulation, with the potential for remote therapy. [ABSTRACT FROM AUTHOR]

In this study, we report an efficient bifunctional electrocatalyst of rhodium telluride (RhTe2) for alkaline water splitting. With the construction of Rh–Te bonds, the catalytic performance as well as stability are boosted. [ABSTRACT FROM AUTHOR]

CoFe2O4 quantum dots (QDs) showed a battery performance 1.79 times higher than that displayed by the benchmark Pt/C–IrO2. Furthermore, a power density of 87 mW cm−2 was achieved for all-solid-state zinc air batteries (ZABs) of CoFe2O4 QDs, implying good prospects of using these QDs in practical applications. [ABSTRACT FROM AUTHOR]

In this work, we report fluorine-doped tungsten sulfide as an exceptional electrocatalyst for H2O2 generation (95% at 0.6 V vs. RHE). The fluorine dopants boost the catalytic efficiency by reducing the binding strength between the catalytic center and OOH* species. [ABSTRACT FROM AUTHOR]

Alkaline phosphatase (ALP) plays a vital role in clinical diagnoses and biomedical research. It is important to develop some convenient but sensitive methods for ALP activity detection. In this study, a multicolor biosensor for ALP activity has been developed based on the peroxidase activity of copper nanoclusters (CuNCs) and etching of gold nanorods (AuNRs). The presence of CuNCs can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue TMB+. In acid solution, TMB+ can cause the etching of AuNRs accompanied by a significant color change of the system. The presence of sodium pyrophosphate (PPi) can inhibit the peroxidase activity of CuNCs, which can be recovered after the addition of ALP. Different ALP added results in the recovery of the catalytic activity of CuNCs to different degrees and generates different amounts of TMB+. This consequently affected the morphology of the AuNRs in the system and results in the output of a vivid color change, which can be recognized with the naked eyes easily without any complicated instruments. The biosensor has a linear relationship with ALP activity in the range of 10.0–80.0 U L−1, and the detection limit is 4.6 U L−1. The proposed method has been applied to detect ALP activity in human serum samples with satisfactory results. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is an active physiological molecule, and its intracellular level has great significance to life functions. In this study, an effective and sensitive method was developed for H2S sensing with dark field microscopy (DFM). The proposed method employed AuNPs as the signal source, DFM as the readout system, and an intelligence algorithm as the image processing and output systems, respectively. The AuNP surface was modified with azido and alkynyl in advance, and then added into a tube cap. As the H2S evaporated from the solution and selectively reduced azido to amino, the click chemistry reaction was inhibited, which resulted in the AuNPs being well dispersed in the solution; otherwise, AuNP aggregation occurred. The scattering colour of single AuNPs could be easily distinguished from that of AuNP aggregations with DFM, and the number or ratio of single AuNPs could also be easily obtained by the custom algorithm. The results showed that the H2S content could be linearly analyzed in a range from 2–80 μM. Furthermore, the proposed sensing strategy has been applied for H2S detection in cell lysate. Compared with the traditional colorimetric method, the results showed no significant difference, indicating the good prospects of the algorithm and proposed H2S sensing method. [ABSTRACT FROM AUTHOR]

Electrical signals are a key factor to promote nerve cell neurogenesis. However, the traditionally used exogenous electrical stimulus mode requires additional equipment and complicated wiring, which is very inconvenient. To date, it has been challenging to provide electrical signals to nerve cells in a non-invasive and wireless controllable way, accompanied by the construction of a biomimetic cell microenvironment for supporting nerve cell survival and functional expression. Herein, a new concept of a light-powered oriented bioactive scaffold for remote and wireless electrical stimulation has been developed. By combining electrospinning and electrospraying, the highly oriented polycaprolactone (PCL) microfibrous scaffold with co-sprayed bioactive collagen and photoelectric poly-3-hexylthiophene nanoparticles (P3HT NPs) was obtained, named as PCL–P3HT–Col, which exhibits a considerable photoelectric effect and vital characteristics of the native nerve extracellular matrix. The results show that a photocurrent ranging from 20–80 pA was obtained by changing the light density of a 530 nm green light source. Further, the specific photoelectric conversion effect trigged by the P3HT NPs promotes the oriented elongation and up-regulation of neuronal characteristic factors in rat pheochromocytoma cells (PC12 cells), which is controlled by L-type voltage-gated calcium channel (L-VGCC) activity. This study provides new insights to engineer self-powered scaffolds towards the non-invasive and wireless-controlled stimulation mode of a variety of cells and tissues. [ABSTRACT FROM AUTHOR]

Efficient electrocatalysts for the hydrogen evolution reaction (HER) in both acidic and alkaline media are prominently important to advance the widespread application of industrial water splitting technology. In this work, we have synthesized ultrasmall rhodium–rhodium phosphide hetero-nanoparticles (3.4 nm, Rh–Rh2P@C) by partial phosphorization of Rh@C at 300 °C together with Na2HPO2. The constructed Rh–Rh2P@C requires only 24 mV and 37 mV overpotentials to reach 10 mA m−2 in 0.5 M H2SO4 and 1 M KOH electrolytes, which are lower than those of Rh@C and Rh2P@C due to the formation of heterointerfaces inducing modulation of local electronic structures and more active sites; as a result, a more moderate hydrogen adsorption–desorption strength is achieved for Rh–Rh2P@C as proved by theoretical calculation. Moreover, the calculated mass activity of Rh–Rh2P@C is 4 orders of magnitude higher than that of the benchmark Pt/C electrocatalyst. Besides, exceptional stability is recorded for Rh–Rh2P@C in both acidic and alkaline electrolytes due to the strong electronic interaction between Rh and Rh2P. This study offers a new strategy to manufacture efficient electrocatalysts for various applications. [ABSTRACT FROM AUTHOR]

As environmental pollution and energy shortages have become global concerns, the construction of highly efficient catalysts using facile and green methods remains a long-term goal. In the present study, we proposed a facile catalyst preparation method in which Ag/TiO2 composites were coated on the surface of the porous pure inorganic crystalline vanadium phosphates (VPO) by a one-step strategy. More importantly, the in situ reduction of Ag nanoparticles was achieved at room temperature without severe conditions or hydrogen atmosphere in which the porous VPO was employed as the reductant. The prepared Ag/VPO@TiO2 composites act as a class of efficient bifunctional catalysts for visible light photodegradation of MB molecules and catalytic reduction of p-nitrophenol (4-NP). Among these samples, the 6.82%Ag/VPO@TiO2 composite exhibited a superior photocatalytic activity in the degradation of MB and an ultrafast reduction rate for 4-NP of about 0.1 mM/40 s. The photocatalytic mechanistic studies revealed that the encapsulated VPO with a narrow band gap not only efficiently enhances the photosensitivity of the TiO2 but also largely facilitates the photogenerated charge separation. The subsequent deposition of Ag NPs is able to further promote electron transfer ability, which leads to the higher photocatalytic activity. Moreover, the contact of Ag NPs with the surface of semiconductor TiO2 can result in an electron-enhanced area in their interface that could effectively facilitate the uptake of electrons by the 4-NP molecules and then improve the reduction activity. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) have been used to quench the electrochemiluminescence (ECL) of a Ru(bpy)32+–tripropylamine (TPA) system for the first time. In addition, this phenomenon has been coupled with duplex specific nuclease-assisted target recycling amplification to develop a highly sensitive ECL biosensor for microRNA. [ABSTRACT FROM AUTHOR]

Efficient nitrogen reduction reaction (NRR) catalysis relies on the active sites of the electrocatalyst being capable of adsorption of hydrogen ions and nitrogen molecules. As has been well reported, nitrogen-doped carbons are efficient electrocatalysts for the hydrogen evolution reaction (HER) due to their ability to adsorb hydrogen ions, to combine them and to release H2. The introduction of other heteroatoms to disturb the successive HER active sites in nitrogen-doped carbon, and to offer binding sites for N2, is beneficial for efficiently catalyzing the NRR. Here, we rationally synthesize boron, nitrogen and fluorine ternary-doped carbon (BNFC) from the carbonization of cigarette butts saturated with the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (C8H15N2BF4). Nitrogen atoms in BNFC are capable of adsorption of hydrogen ions, and the adjacent B or F heteroatoms offer Lewis acid sites for chemisorption of N2; in the case of this synergistic catalysis, a boosted electrocatalytic activity toward the NRR with an NH3 yield rate of 41 μgNH3 h−1 mgcat.−1 and a faradaic efficiency as high as 14% at −0.4 V vs. reversible hydrogen electrode (RHE) are recorded for BNFC in 0.05 M H2SO4 electrolyte. Moreover, a comparably high NH3 yield rate (39 μgNH3 h−1 mgcat.−1) and faradaic efficiency (16%) at −0.4 V vs. RHE are also recorded in 0.1 M NaOH electrolyte due to the capability of water dissociation and adsorption of generated hydrogen ions by the nitrogen atoms in BNFC. In addition, due to the modulated electronic structure of the carbon atoms by means of heteroatom doping, BNFC also exhibits a Pt-like oxygen reduction reaction (ORR) activity with a half-wave potential of 836 mV vs. RHE and superior oxygen evolution reaction (OER) demanding a low overpotential of 313 mV to achieve 10 mA cm−2. As a consequence, the assembled rechargeable zinc–air batteries (ZABs) perform at a 1.8-fold higher power density than commercial Pt/C–IrO2 and sustain this for 2300 cycles with minimal degradation in performance. The battery performance of all-solid-sate ZABs also outperforms that of commercial Pt/C–IrO2 systems and can power the OER–NRR coupled device to electrochemically generate NH3. [ABSTRACT FROM AUTHOR]

A nanoscale hybrid material (V2O5–Al13) for highly efficient alcohol oxidation is synthesized through electrostatic self-assembly between oppositely charged Keggin Al13 polyoxocations and exfoliated V2O5 nanosheets. The analyses by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy and structural consideration based on charge balance indicate that the Keggin Al13 ions could be sparsely distributed in the nanosheet galleries. The as-prepared catalyst successfully achieved high catalytic activity toward alcohols (96.8% sel.) with the oxygen molecule as an ideal oxidant under mild conditions. Also, the nanohybrid showed an outstanding adsorption capability for benzyl alcohol (773 mg g−1). In comparison to individual exfoliated V2O5 nanosheets and bulk V2O5, the V2O5–Al13 nanohybrid catalyst exhibited superior catalytic activity and selectivity under the same experimental conditions. The results highlight the outstanding functionality of the V2O5–Al13 nanohybrid as an efficient oxidation catalyst. A detailed study of its structure–activity relationship showed that the high performance of the V2O5–Al13 nanohybrid is attributed to the adsorption–catalysis synergistic effect between V2O5 and Al13. [ABSTRACT FROM AUTHOR]

Boron and nitrogen dual-doped carbon nanospheres (BNC-NSs) show exceptional electrocatalytic activity toward the nitrogen reduction reaction, with an NH3 yield rate of 15.7 μgNH3 h−1 mgcat.−1 and faradaic efficiency of 8.1% at −400 mV vs. RHE in 0.05 M H2SO4 electrolyte. Meanwhile, stable electrocatalyst activity was also achieved for the BNC-NS electrocatalyst. [ABSTRACT FROM AUTHOR]

Boron and nitrogen dual-doped carbon nanospheres (BNC-NSs) show exceptional electrocatalytic activity toward the nitrogen reduction reaction, with an NH3 yield rate of 15.7 μgNH3 h−1 mgcat.−1 and faradaic efficiency of 8.1% at −400 mV vs. RHE in 0.05 M H2SO4 electrolyte. Meanwhile, stable electrocatalyst activity was also achieved for the BNC-NS electrocatalyst. [ABSTRACT FROM AUTHOR]

Ultrafine (5 nm) cobalt nitride nanoparticles supported on carbon nanotubes (CoN/CNT) are reported as air electrodes for rechargeable zinc–air batteries (ZABs). CoN/CNT exhibits 2.4 fold higher battery performance than commercial Pt/C-IrO2. [ABSTRACT FROM AUTHOR]

Highly efficient catalytic oxidation toward cyclohexane with molecular oxygen (O2) is still one of the most important reactions in current catalytic chemistry. Demonstrated here is how to effectively enhance the catalytic aerobic oxidation of cyclohexane over a mixed-valence {V16} cluster-based metal–organic framework (NENU-MV-1) through rational size regulation. The average particle size of NENU-MV-1 was tuned notably from 25 μm to 500 nm by changing reaction temperature, concentration and molar ratio of metal source to ligand during solvothermal reactions. Remarkably, NENU-MV-1 with 500 nm particle size yields a higher conversion efficiency of cyclohexane (24.6%) and selectivity of the mixture of cyclohexane and cyclohexone (99%) than that of bulk crystalline NENU-MV-1. The kinetic study signified that catalysts with smaller particle size showed a faster catalytic rate, which is mainly attributed to the fact that catalysts with smaller particle size are able to expose more active sites and then more fully contact with substrate molecules. In addition, the mixed-valence {V16} cluster-based oxidation catalysts exhibited higher activity than the single-valence vanadium cluster-based oxidation catalysts and VIV and VV-based physical mixture. An in-depth investigation of the reason for the high reactivity of NENU-MV-1 indicated that there may be a synergistic catalytic effect of VIV–VV centers. [ABSTRACT FROM AUTHOR]

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon (W/W2C@NPC) fabricated by the carbonization of in situ polymerized polyaniline (PANI) and phosphotungstic acid require low overpotentials of 55 mV and 82 mV vs. RHE to achieve a cathodic current density of 10 mA cm−2 in acidic and alkaline electrolytes, respectively. [ABSTRACT FROM AUTHOR]

Here, we report a facile method to synthesize ruthenium phosphides with diameter 1 nm and an amorphous structure at room temperature. Only 31 mV vs. RHE overpotential is required to deliver 10 mA cm−2 and no degradation in hydrogen evolution reaction (HER) performance is recorded after 24 h of catalysis at 100 mA cm−2. [ABSTRACT FROM AUTHOR]

Transdermal delivery of diclofenac sodium (DS) has drawn much attention for the advantages of avoiding first-pass metabolism, reduced systemic toxicity and better patient compliance, but the successful translation of reported transdermal drug delivery systems (TDDSs) is still limited by poor skin permeability and uncontrollable drug release. Herein, we designed and fabricated a novel ultrasound responsive TDDS by embedding DS-loaded polyester microcapsules into a hydrogel patch based on four-armed poly(ethylene glycol). The rational design endows the microcapsule-embedded hydrogel patch with good biocompatibility, excellent skin-adhesion properties and well-controlled ultrasound responsive release behavior. More importantly, by employing ultrasound as a simultaneous trigger of drug release and efficient penetration enhancer, the encapsulated drug could be released and pass through the skin barrier rapidly under ultrasound, while without the action of ultrasound, a negligible amount of drug was released and penetrated into the subcutaneous tissues in ex vivo and in vivo transdermal drug release experiments, indicating that improved and controllable transdermal delivery of DS was achieved. Our work demonstrated that the microcapsule-embedded hydrogel patch may be a promising candidate as an ultrasound responsive and enhanced TDDS of DS for treating diseases such as arthritis and topical soft tissue injuries. [ABSTRACT FROM AUTHOR]

A novel photocatalytic acylarylation of unactivated alkenes using diaryliodonium salts as the arylation reagent is described. The reaction produces a variety of 2-benzyl indanones, 3,4-dihydronaphthalen-1(2H)-ones, and 2,3-dihydroquinolin-4(1H)-ones in promising yields with excellent diastereoselectivity under very mild conditions, which may be appealing for the synthesis of biologically active molecules. [ABSTRACT FROM AUTHOR]

Hierarchically porous metal–organic frameworks combining the merits of micropores with high surface areas and mesopores/macropores with large diffusion channels are highly desired in catalysis, especially for reactions involving large substrates. In this work, a simple and common solvent templating strategy for the construction of hierarchically micro- and mesoporous polyoxometalate-based metal–organic frameworks by a gel-like/freeze-drying method was achieved. Fast nucleation and interconnection of nanoparticles with micropores were realized in the gel-like stage. Subsequently, the synthesized mesopores were strengthened by the squeezing by ice crystals due to volumetric swelling during the process of freezing water into ice. The hierarchically porous material showed improved catalytic activities for the oxidation of alcohols compared to the catalyst without hierarchical pores, due to it having more easily accessible catalytic sites and the acceleration of mass transfer. [ABSTRACT FROM AUTHOR]

Proton conductivity is traditionally affected by proton concentration, mobility, hopping sites, etc. in metal–organic frameworks (MOFs). The influence of the profile of proton-conducting pathway has not been demonstrated due to lack of a suitable model. MIL-101 contains two types of tunnels with zigzag and linear profiles constructed by cages with different sizes. However, it is hard to construct an exclusive proton-conducting pathway with only one profile in MIL-101 because the introduced carriers usually locate without targeting a specific location. Keggin-type H3PW12O40 (HPW) has a unique nano size, which is between the window sizes of the cages in MIL-101, strong acidity, good stability, and abundant proton-hopping sites. Herein, two types of hydrogen bond networks were constructed by situating HPWs in the targeting pores of MIL-101. Linear pathways provide about 2.1-fold faster proton diffusion rates compared to zigzag pathways. Further modification of an HPW-impregnated MIL-101 with flexible polyamine resulted in a conductivity of 1.52 × 10−2 S cm−1. [ABSTRACT FROM AUTHOR]

Herein, an electrochemiluminescence (ECL) biosensor for ultrasensitive and specific detection of Kras mutant genes has been developed on the basis of the high discrimination capability of locked nucleic acid (LNA) and dual signal amplification techniques including DNA walkers and hyperbranched rolling circle amplification (HRCA). [ABSTRACT FROM AUTHOR]