Epinephrine (EP) is a crucial neurotransmitter in the central nervous system. However, an abnormal level of EP in biological fluids can lead to various diseases. Therefore, it is essential to rapidly and accurately detect EP content. Herein, electrically stimulated patterned Au@Ag nanoarrays with laccase-mimicking activity were designed for the dual-mode detection of EP concentration. The patterned Au@Ag nanoarrays exhibit excellent electrochemical properties and electrically stimulated laccase-mimicking activity. They provide sensitive electrochemical responses for detecting EP content. Simultaneously, the Au@Ag nanoarrays can catalyze the oxidation of EP, enabling its detection through a colorimetric process. This dual-mode approach achieves the detection of EP content over a wide linear range of 0.5-200 mu M, with a low detection limit of 0.152 mu M. Furthermore, the utility of these nanoarrays for sensing EP in human serum was evaluated. This work provides a convenient method using patterned nanozyme array for the visible, rapid and accurate detection of EP content. It provides the important implication for the development of portable and reliable on-site analytical instruments.

Ensuring an appropriate nitrite level in food is essential to keep the body healthy. However, it still remains a huge challenge to offer a portable and low-cost on-site food nitrite analysis without any expensive equipment. Herein, a portable integrated electrochemical sensing system (IESS) is developed to achieve rapid on-site nitrite detection in food, which is composed of a low-cost disposable microfluidic electrochemical patch for few-shot nitrite detection, and a reusable smartphone-assisted electronic device based on self-designed circuit board for signal processing and wireless transmission. The electrochemical patch based on MXene-Ti3C2Tx/multiwalled carbon nanotubes-cyanocobalamin (MXene/MWCNTs-VB12)-modified working electrode achieves high sensitivity of 10.533 mu A mm-1 and low nitrite detection limit of 4.22 mu m owing to strong electron transfer ability of hybrid MXene/MWCNTs conductive matrix and high nitrite selectivity of VB12 bionic enzyme-based ion-selective layer. Moreover, the portable IESS can rapidly collect pending testing samples through a microfluidic electrochemical patch within 1.0 s to conduct immediate nitrite analysis, and then wirelessly transmit data from a signal-processing electronic device to a smartphone via Bluetooth module. Consequently, this proposed portable IESS demonstrates rapid on-site nitrite analysis and wireless data transmission within one palm-sized electronic device, which would pave a new avenue in food safety and personal bespoke therapy. A portable integrated electrochemical sensing system (IESS) is developed to realize its rapid on-site few-shot nitrite analysis and wireless data transmission capability within one palm-sized electronic device. The utilization of hybrid MXene/MWCNTs conductive matrix and VB12 bionic enzyme-based ion-selective layer as electrode materials achieves excellent nitrite analysis performances.image

Abnormal levels of glutathione (GSH) and ferric ions (Fe3+) can break the redox balance in the human body and lead to neurodegenerative diseases. However, it is still challenging to detect Fe3+ and GSH simultaneously in the coexisting system. Herein, a colorimetric/fluorescent sensing platform based on copper sulfide @ carbon dots nanocomposites (CuS@CDs NCs) is constructed for simultaneously detecting GSH and Fe3+ in the coexisting system. CuS@CDs NCs show photothermal effect, leading to the improvement of peroxidase-like activity of CuS@CDs NCs for colorimetric analysis of GSH. Moreover, Fe3+ can be detected through the fluorescence quenching of CuS@CDs NCs based on the inner filter effect (IFE). The results show the detection limits toward GSH and Fe3+ as low as 0.0527 mu M and 0.0163 mu M, respectively. In order to realize the detection of GSH and Fe3+ in the coexisting system, hydrogen peroxide is added into the system to reduce the mutual interference between GSH and Fe3+. The sensing strategy reaches wider linear GSH detection range of 0-500 mu M in the coexisting system. The serum samples are successfully analyzed, suggesting the feasibility of sensing strategy. This sensing platform provides a new pathway for multicomponent biodetection in the coexisting system.

Sensitive detection and effective inactivation of bacteria are essential in preventing foodborne bacterial infection that poses a significant threat to human health. Herein, a near-infrared (NIR)-driven multifunctional photoelectrochemical (PEC) biosensor was constructed for detection and inactivation of S. aureus. Based on the covalent bonding between amine and carboxyl groups, carboxyl-functionalized SA31 aptamer was immobilized on the PDA/MnO2 photoelectrode. In the presence of S. aureus, SA31 aptamer can specifically capture S. aureus, causing the decrease of photocurrent signal owing to steric hindrance effect. Leveraging photocurrent-off signal, there existed a satisfied linear relationship between the photocurrent variation and the logarithm of S. aureus concentration, achieving a wide linear range from 10 to 107 CFU/mL with a low detection limit of 2.0 CFU/mL. Notably, PDA/MnO2 with peroxidase-like activity facilitated the catalytic oxidation of S. aureus with assistance of hydrogen peroxide (H2O2) to cause the inactivation of S. aureus. Desorption of inactivated S. aureus from the photoelectrode led to a recovery of photocurrent signal, enabling a "signal on" switch. Simultaneously, the excellent photothermal performance of the PDA/MnO2 converted light energy into heat energy under the irradiation of NIR light (808 nm, 1.5 W/cm2), triggering the synergistic antibacterial effect against S. aureus (97.36%). This work provides a novel strategy for fabricating the detection and inactivation of bacteria in practical applications.

BACKGROUND:Adrenaline and glucose are essential biomarkers in human body for maintaining metabolic balance. Abnormal levels of adrenaline and glucose are associated with various diseases. Therefore, it is important to design portable, on-site devices for rapid adrenaline and glucose analysis to safeguard health. Traditional paper-based analytical devices (μPADs) for multiplexed detection typically required multiple recognized probes, increasing the cost and complexity. Moreover, non-uniform color distribution, caused by lateral chromatographic elution effect, reduced results accuracy. Hence, it is necessary to construct visualized μPADs with controlled flow capability using single sensing probe for simultaneous adrenaline and glucose analysis in point-of-care testing (POCT). RESULTS:The portable multiplexed 3D-folded μPADs have been developed for the visualized, accurate and simultaneous detection of adrenaline and glucose, employing Ag-doped copper sulfide nanoparticles (Cu1-xAgxS NPs) as multifunctional sensing probe. The μPADs integrated the sampling entrance layer, buffer layer and test layer into a single device through wax printing, allowing the analyte solution to flow vertically from buffer zones to detection zones, thereby minimizing lateral chromatographic elution effect. Cu1-xAgxS NPs, exhibiting laccase-like and peroxidase-like multi-enzyme activities, were modified on various detection zones of μPADs for multiplex colorimetric analysis of adrenaline and glucose. Based on Cu1-xAgxS-induced colorimetric reactions, the orange-red and blue colors were generated in adrenaline and glucose detection zones, respectively. Subsequently, color signals were converted into RGB values via smartphone application (APP) for rapid and intelligent results analysis. The Cu1-xAgxS-incorporated μPADs exhibited colorimetric uniformity and accuracy with limit of detection (LOD) of 10.2 nM and 11.5 μM, respectively. SIGNIFICANCE:The adjustable laccase-like and peroxidase-like activities of Cu1-xAgxS NPs induced by Ag doping provide a new perspective for multiple biomarkers analysis. Benefiting from the excellent multienzyme activity of Cu1-xAgxS NPs, μPADs can perform on-site, visual and multiplex analysis using a single probe, demonstrating their potential for POCT in personal healthcare. The 3D folded Cu1-xAgxS-incorporated μPADs with integrated horizontal and vertical flows exhibit uniform color signals for obtaining accurate detection results.

The rapid emergence of drug-resistant bacteria has attracted great attention to exploring advanced antibacterial methods. However, single-modal antibacterial therapy cannot easily eliminate drug-resistant bacteria completely due to its low efficacy. Therefore, it is essential to achieve multi-modal antibacterial therapy effectively. Herein, a dual-modal ROS generator was designed based on photosensitive PDA-MnO2@Ce6/liposome (PMCL) nanozymes for synergistic chemo-photodynamic therapy. PMCL nanozymes adhere to bacteria through liposome-membrane fusion. Meanwhile, PMCL catalyzes endogenous hydrogen peroxide (H2O2) to generate hydroxyl radicals (˙OH) and singlet oxygen (1O2) under laser irradiation. Furthermore, the photothermal effect can accelerate the generation of ROS. Based on dual-enzyme activities (mimicking peroxidase and catalase) and photodynamic properties, PMCL achieves powerful antibacterial efficacy and mature bacterial biofilm eradication. With the synergistic chemo-photodynamic effects, bacterial populations decrease by >99.76% against Gram-positive S. aureus and Gram-negative E. coli. Notably, the synergistic antibacterial properties of PMCL nanozymes are further explored using a mouse wound model of S. aureus infection. This work fabricated an efficient dual-modal ROS generator to kill bacteria, further providing a new strategy for treating wound infection.

Photodynamic therapy (PDT) efficiency is directly affected by the reactive oxygen species (ROS) generated by photosensitizers. However, ROSs' ultrashort life span and limited diffusion distance restrict the PDT efficiency. Therefore, it is important to control the delivery strategy of photosensitizers for PDT treatment. Herein, the core-satellite nanoreactors were fabricated with oxygen generation and ROS diffusion properties. The hollow CuS encapsulating horseradish peroxidase (HRP) was combined with the cationic photosensitizers (PEI-Ce6). The unique photosensitizers delivery strategy makes the nanoreactors achieve ROS diffusion-enhanced PDT effect. First, HRP in “core” (HRP@CuS) can decompose hydrogen peroxide (H2O2) to O2, increasing O2 levels on the surface of the nanoreactor. Second, the Ce6 molecules covalent-linked with PEI are uniformly dispersed on the surface of CuS as a “satellite”, avoiding Ce6 aggregation and causing more Ce6 molecules be activated to produce more 1O2. Due to the Ce6 was on the surface of the CuS nanocages, the generated ROS may ensure a larger diffusion range. Meanwhile, the inherently CuS nanocages exhibit photothermal and photoacoustic (PA) effect. The photothermal effect further enhances the ROS diffusion. Under the guidance of PA imaging, nanoreactors exhibit highly efficient hypoxic tumor ablation via photodynamic and photothermal effect. Overall, the core-satellite nanoreactors provide an effective strategy for tumor therapy, further promoting the research of photosensitizers delivery.

The development of cuprous oxide (Cu2O) photocathode for photoelectrochemical (PEC) water splitting confronts charge recombination and photocorrosion. Herein, a facile strategy for wrapping Cu2O photocathode with Cu ions intercalated graphene oxide (Cu-GO) was proposed to realize efficient PEC water splitting. The intercalating GO with Cu ions could reduce the bandgap and enhance the carrier mobility of Cu-GO. The as-formed Cu-GO could suppress surface charge recombination and accumulation of the Cu-GO/Cu2O photocathode by improving the interfacial charge transfer, which strengthens electron extraction and restrains photocorrosion. The Cu-GO/Cu2O photocathode achieved a high photocurrent density of - 7.03 mA cm(-2) (at 0 V vs. RHE) under AM 1.5 G illumination and excellent photostability for PEC water splitting. This work provides a simple way to design Cu2O-based photocathodes with reliable charge transfer layers for efficient PEC water splitting.

Staphylococcus aureus (S. aureus) infections pose a serious threat to human health worldwide. Therefore, selective and accurate detection of S. aureus is necessary for preventing infections. Herein, we design the colorimetric-electrochemical sensing platform based on specific oligonucleotide (SA31 aptamer)-tunable oxidase-like activity of mesoporous polydopamine/MnO2 (MPDA/MnO2) nanozymes for the S. aureus detection. The MPDA/MnO2 nanozymes possess excellent oxidase-like activity and electrochemical property. MPDA/MnO2 nanozymes can catalyze the oxidation of TMB to generate TMB+ (blue color) and TMB2+ (yellow color) products. The oxidase-like activity of MPDA/MnO2 can be inhibited when the SA31 is adsorbed on the surface of the nanozymes. In the presence of S. aureus, SA31 aptamer desorbs from MPDA/MnO2 surface based on the specific identification between S. aureus and aptamer, resulting in the recovery of their oxidase-like activity. Based on the different oxidative degree of TMB, the color of sensing solution changes from blue to yellow, the electrochemical signals also have changed simultaneously. The colorimetric-electrochemical sensing platform can accurately detect S. aureus, showing a low detection limit in 3 CFU/mL (S/N = 3). Furthermore, the dual-mode sensing platform can be utilized for the accurate and specific detection of S. aureus in real sample with the recovery of 95.15%- 115.28%. This work based on SA31 aptamer-tunable oxidase-like activity of MPDA/MnO2 nanozymes provides a dual-mode assay for specific and accurate detection of S. aureus.

Carbon dots/Prussian blue nanoparticles (CDs/PBNPs) with fluorescence (FL) performance and peroxidase-like activity are synthesized by a simple two-step method. The FL of CDs/PBNPs can be effectively quenched by Fe3+. Fe3+ can accelerate the peroxidase-like activity of CDs/PBNPs. More excitingly, the peroxidase-like activity of CDs/PBNPs could be further enhanced due to the influence of the photothermal effect. Based on the FL property and enhanced peroxidase-like activity, a cascade strategy is proposed for detection of Fe3+ and free cholesterol. CD/PBNPs act as FL probe for detection of Fe3+. The enhanced peroxidase-like activity of CDs/PBNPs can also be used as colorimetric probe for the detection of free cholesterol. The detection ranges of Fe3+ and free cholesterol are 4–128 μM and 2–39 μM, and the corresponding limit of detections are 2.0 μM and 1.63 μM, respectively. The proposed strategy has been verified by the feasibility determination of Fe3+ and free cholesterol, suggesting its potential in the prediction of disease.

Since the COVID-19 pandemic outbreaks, the utilization of medical masks plays a critical role in reducing the infected risk. However, constructing multifunctional masks to achieve simultaneously self-sterilization, reusability, and respiratory monitoring capability remains still a huge challenge. Herein, a reusable Ag micro-mesh film-based mask is proposed, which enables the capabilities of electrothermal sterilization and self-powered real-time respiratory monitoring. Highly conductive Ag micro-mesh films prepared by continuous draw spinning method demonstrate excellent electrothermal performances for thermal sterilization and serve as working electrode to fabricate triboelectric nanogenerator (TENG) for real-time respiratory monitoring, respectively. Under a low driving voltage of 3.0 V, the surface temperature of Ag micro-mesh film enables a quick increase to over 60 °C within 30 s, which endows thermal sterilization against S. aureus with antibacterial efficiency of 95.58 % within 20 min to achieve the self-sterilization of medical masks. Furthermore, a self-powered alarm system based on the fabricated TENG as respiratory monitor is developed for real-time respiratory monitoring to render a timely treatment for patients in danger of tachypnea and apnea. Consequently, this work has paved a new and practical avenue to achieve reusable multifunctional masks with capabilities of electrothermal sterilization and real-time respiratory monitoring in clinical medicine.

Constructing efficient and stable photocathodes for photoelectrochemical carbon dioxide reduction reaction (PEC CO2RR) is a bold approach to solving the carbon problem. Adenine-functionalized graphene oxide coated Cu2O (A-GO/Cu2O) photocathode for PEC CO2RR is designed in this work. The A-GO charge transfer layer can improve photoelectrochemical activity and stability of the Cu2O photocathode by facilitating the electrons transfer. During PEC CO2RR, the A-GO/Cu2O photocathode shows a high Faradaic efficiency of 69.25% for menthol production. The Lewis-basic and pyrimidine N sites in A-GO can assist the Cu2O in the process of PEC CO2RR. Under 1.5AM, the photocurrent density of the A-GO/Cu2O photocathode is 2.74 mA cm-2 at -1.1 V (vs Ag/AgCl), which is 2.23 and 1.56 times higher than that of bare Cu2O and GO/Cu2O photocathodes, respectively. Coating biomimetic molecule functionalized GO as a charge transfer layer was a crucial strategy for building effective and stable Cu2O-based photocathodes for PEC CO2RR, as illustrated in this study.

It is greatly significant and difficult to realize the purpose of natural enzyme free and "one-step" for traditional colorimetric urine glucose detection. Here, ultra-small Ag2-xCuxS nanoparticles (NPs) with tandem enzyme-like activity, i.e. they simultaneously exhibit glucose oxidase (GOx)- and peroxidase-like activities, are developed for tandem glucose oxidation and colorimetric H2O2 detection. Cu doping content has a great influence on the enzyme-like activity. Ag1.8Cu0.2S NPs (i.e. Ag2-xCuxS NPs with 10 % Cu) exhibit the best catalytic performance. The tandem enzyme-like activity can be further enhanced to similar to 10 times under laser irradiation due to photothermal effect. Furthermore, accurate glucose detection has been realized in unprocessed human urine based on the photothermal-enhanced tandem enzyme-like activity of Ag1.8Cu0.2S NPs. This natural enzyme free and "one-step" colorimetric glucose detection strategy exhibits the potential application of the new generation of tandem enzyme-like nanomaterials.

利用从全国采集的土样中收集到的28个品系的昆虫病原线虫,分离并筛选出28株高毒力共生菌株,对高毒力菌株的毒素进行初步提取,利用水稻恶苗病菌进行抑菌活性测定,结果表明,共生菌NC34-3B的毒素对水稻恶苗病菌抑菌活性最高,抑菌圈半径为17.50 mm.