Conducting polymer functionalized Cu-metal organic framework-based electrochemical immunosensor for rapid and sensitive quantitation of Escherichia coli O157:H7.

Escherichia coli (E. coli) O157:H7 is an important food-borne pathogen that can cause hemorrhagic diarrhea and enteritis in humans and animals. Realizing the rapid quantitation of E.

Implementation of π-π interaction in AuNPs@GDY to boost the bioelectrocatalysis in enzymatic biofuel cells.

The main challenges (sluggish electron transfer, low energy density) hinder the future application of enzymatic biofuel cells (EBFCs), which urgent to take effective measures to solve these issues. In this work, a composite of Au nanoparticles decorated graphdiyne (AuNPs@GDY) is fabricated and employed as the carrier of enzyme (G6PDH), and a mechanism based on π-π interaction of electron transfer is proposed to understand bioelectrocatalysis processes. The results show that the AuNPs@GDY composite exhibits the highest current density among the three materials (GDY, AuNPs, and AuNPs@GDY), which is 3.

Electromagnetic Field Drives the Bioelectrocatalysis of γ-FeO-Coated CN32 to Boost Extracellular Electron Transfer.

The microbial hybrid system modified by magnetic nanomaterials can enhance the interfacial electron transfer and energy conversion under the stimulation of a magnetic field. However, the bioelectrocatalytic performance of a hybrid system still needs to be improved, and the mechanism of magnetic field-induced bioelectrocatalytic enhancements is still unclear. In this work, γ-FeO magnetic nanoparticles were coated on a CN32 cell surface and followed by placing in an electromagnetic field.

Graphdiyne marries PEDOT:PSS to form high-stable heterostructure from 2-unstable components toward ultra-low detection limit of uric acid detection in sweat.

PSS has been used as a biomimetic uric acid (UA) sensor but suffers from unfortunate low detection limit (LOD), narrow detection range and poor stability. Herein, we get graphdiyne (GDY) marry PEDOT:PSS to create a very stable GDY@PEDOT:PSS heterostructure for a biomimetic UA sensor, which accomplishes the lowest LOD (6 nM), the widest detection range (0.03 μM-7 mM) and the longest stability (98.

Tuning metal atom doped interface of electrospinning nanowires to toward fast bioelectrocatalysis.

Metal doping plays a key role in overcoming inefficient extracellular electron transfer between electrode interface and electricity-producing microorganisms. However, it is unknown whether different metals play distinctive roles in the doping process. Herein, three different metal ions (Fe, Ni and Cu) are added to the spinning precursor to obtain the corresponding electrospinning metal doped carbon nanofibers.

Integrated Sandwich-Paper 3D Cell Sensing Device to Wirelessly Monitor HO Released from Living Cells.

Point-of-care testing (POCT) has attracted great interest because of its prominent advantages of rapidness, precision, portability, and real-time monitoring, thus becoming a powerful biomedical device in early clinical diagnosis and convenient medical treatments. However, its complicated manufacturing process and high expense severely impede mass production and broad applications. Herein, an innovative but inexpensive integrated sandwich-paper three-dimensional (3D) cell sensing device is fabricated to wirelessly detect HO released from living cells.

Graphdiyne chelated AuNPs for ultrasensitive electrochemical detection of tyrosine.

Tyrosine (Tyr) is a kind of amino acid that can regulate emotions and stimulate the nervous system, and it is of great importance to realize its ultrasensitive detection. A unique material of graphdiyne chelated AuNPs (GDY@AuNPs) is designed and developed to realize high-performance electrochemical sensing of Tyr. GDY promotes the absorption of Tyr π-π interaction, and its CC strongly chelates with AuNPs for greatly improved sensitivity.

Doping molybdenum oxides with different non-metal atoms to promote bioelectrocatalysis in microbial fuel cells.

The sluggish extracellular electron transfer has been known as one of the bottlenecks to limit the power density of microbial fuel cells (MFCs). Herein, molybdenum oxides (MoO) are doped with various types of non-metal atoms (N, P, and S) by electrostatic adsorption, followed by high-temperature carbonization. The as-prepared material is further used as MFC anode.

Electrospinning Mo-Doped Carbon Nanofibers as an Anode to Simultaneously Boost Bioelectrocatalysis and Extracellular Electron Transfer in Microbial Fuel Cells.

The sluggish electron transfer at the interface of microorganisms and an electrode is a bottleneck of increasing the output power density of microbial fuel cells (MFCs). Mo-doped carbon nanofibers (Mo-CNFs) prepared with electrostatic spinning and high-temperature carbonization are used as an anode in MFCs here. Results clearly indicate that MoC nanoparticles uniformly anchored on carbon nanowire, and Mo-doped anodes could accelerate the electron transfer rate.

Screen printed electrodes on interfacial Pt-CuO/carbon nanofiber functional ink for real-time qualification of cell released hydrogen peroxide.

Screen printed electrode (SPE) on carbon-based inks exhibits promising applications in biosensing, environment protection and food safety. We report here a unique carbon-based material comprising Pt-CuO nanocrystal interfacially anchored on functionalized carbon nanofiber (Pt-CuO@FCNF) and its functional ink to build SPE for ultrasensitive detection of cell released HO. Pt-CuO@FCNF is fabricated using a one-pot and mass production method through direct pyrolysis of Pt and CuO precursors together with FCNF.

Interfacial Regulation of ZIF-67 on Bacteria to Generate Bifunctional Sensing Material on Chip for Qualifying Cell-Released Reactive Oxygen Species.

Cell's activities are highly dependent on signal molecules, of which reactive oxygen species of the superoxide anion (O) and hydrogen peroxide (HO) are important ones that always work together to regulate biological processes such as apoptosis and oxidative stress. It is of significance to realize simultaneous qualification of O and HO but it still faces challenges particularly in live-cell assay with a complex environment. We report the design of a bifunctional sensing material by interfacially regulating ZIF-67 on bacteria to generate cobalt nanoparticles/nitrogen-doped porous carbon nanorods (Co/N-doped CNRs) and its sensing chip for qualifying cell-released O and HO.

Synthesis of NiO/Nitrogen-Doped Carbon Nanowire Composite with Multi-Layered Network Structure and Its Enhanced Electrochemical Performance for Supercapacitor Application.

Multi-layered NiO nanowires linked with a nitrogen-doped carbon backbone grown directly on flexible carbon cloth (NiO/NCBN/CC) was successfully fabricated with a facile synthetic strategy. The NiO/NCBN/CC was further used as a binding-free electrode for flexible energy storage devices, showing a boosted performance including a high capacitance of 1039.4 F g at 1 A g and an 83.

Single-Atom Iron Anchored on 2-D Graphene Carbon to Realize Bridge-Adsorption of O-O as Biomimetic Enzyme for Remarkably Sensitive Electrochemical Detection of HO.

Single-atom catalysis is mainly focused on its dispersed high-density catalytic sites, but delicate designs to realize a unique catalysis mechanism in terms of target reactions have been much less investigated. Herein an iron single atomic site catalyst anchored on 2-D N-doping graphene (Fe-SASC/G) was synthesized and further employed as a biomimetic sensor to electrochemically detect hydrogen peroxide, showing an extremely high sensitivity of 3214.28 μA mM cm, which is much higher than that (6.

Vanadium pentoxide flat-nanofiber networked thin layer-structure to initiate intercalated polymerization for rapidly producing superior conductive hydrogel and its biomimetic hydrogen peroxide sensing application.

Poly(3,4-ethylenedioxythiophene) (PEDOT)-based hydrogel has been studied extensively due to its low cost, good chemical/mechanical stability, printability and high biocompatibility, but still suffers from its relatively low conductivity and complex synthesis method. In this work, we use vanadium pentoxide (VO) flat-nanofiber networked thin layer-structure to boost EDOT-intercalation reaction for rapidly producing fiber-reinforced conductive gel (FCG), achieving superior conductivity of 10 S cm and extremely fast production time (10 s). The superior FCG formation mechanism is ascribed to the VO flat-nanofiber networked thin layer-structure allowing EDOT rapidly penetrating to inter-layers and replacing inside water molecules for polymerization to high-conductive FCG.

Highly stable branched cationic polymer-functionalized black phosphorus electrochemical sensor for fast and direct ultratrace detection of copper ion.

Copper ions (Cu) is an indispensable trace element in the process of metabolism and intake of excessive Cu may lead to fatal diseases such as Alzheimer's disease. It is highly demanding to develop a sensitive, selective and convenient method for Cu detection. In this work, thin-layer structured polyethyleneimine (PEI) decorated black phosphorus (BP) nanocomposite is one-step synthesized for an electrochemical sensor toward direct detection of Cu.

Screen-printed analytical strip constructed with bacteria-templated porous N-doped carbon nanorods/Au nanoparticles for sensitive electrochemical detection of dopamine molecules.

Dopamine (DA) as an important neurotransmitter plays an important role in physiological activities, and its abnormal level can cause diseases such as Parkinson's disease. However, the clinical analysis of DA mainly relies on time-consuming and expensive liquid chromatography and molecular spectrometer. We present here a design and fabrication of inexpensive strip sensor constructed from screen printed electrodes for sensitive and selective detection of DA.

Nitrogen doping to atomically match reaction sites in microbial fuel cells.

Direct electron transfer at microbial anodes offers high energy conversion efficiency but relies on low concentrations of redox centers on bacterium membranes resulting in low power density. Here a heat-treatment is used to delicately tune nitrogen-doping for atomic matching with Flavin (a diffusive mediator) reaction sites resulting in strong adsorption and conversion of diffusive mediators to anchored redox centers. This impregnates highly concentrated fixed redox centers in the microbes-loaded biofilm electrode.

A high-energy-state biomimetic enzyme of oxygen-deficient MnTiO nanodiscs for sensitive electrochemical sensing of the superoxide anion.

It is of great importance to determine the superoxide anion (O2˙-), a kind of active free radical that plays important roles in catalytic and biological processes. We present here a high-energy-state biomimetic enzyme with extraordinary activity for O2˙- by inducing surface oxygen defects in MnTiO3 nanodiscs. Oxygen defects enable surface rich active Mn sites with high oxidation ability, which significantly promote the adsorption and electro-oxidation of O2˙-.

Atomic matching catalysis to realize a highly selective and sensitive biomimetic uric acid sensor.

A main challenge for biomimetic non-enzyme biosensors is to achieve high selectivity. Herein, an innovative biomimetic non-enzyme sensor for electrochemical detection of uric acid (UA) with high selectivity and sensitivity is realized by growing Prussian blue (PB) nanoparticles on nitrogen-doped carbon nanotubes (N-doped CNTs). The enhancement mechanism of the biomimetic UA sensor is proposed to be atomically matched active sites between two reaction sites (oxygen atoms of 2, 8-trione, 6.

A multi-component CuO@FePO core-cage structure to jointly promote fast electron transfer toward the highly sensitive in situ detection of nitric oxide.

Electrochemical sensors actually involve an electrocatalytic process in efficient and selective energy conversion. In this work, we use different components to innovatively produce a core@cage material, in which the outer cage, iron phosphate, offers a high electrocatalytic ability to electrochemically oxidize NO, while the inner material, cuprous oxide, could absorb the intermediary HO- ions to kinetically promote NO oxidation for fast electron transfer, resulting in a strong synergistic effect. The unique core@cage structure also increases the active surface area and provides plenty of channels via the porous cage for significantly enhanced mass transport.

Flexible electronic skin with nanostructured interfaces via flipping over electroless deposited metal electrodes.

A novel and simple method was developed to quickly pattern and transfer electrodes with nanostructures for fabricating flexible electronic skin (E-skin). A nano/micro-structure embedded Cu electrode can be fabricated from a solution process-based electroless deposition (ELD) on a frosted plastic substrate and subsequently flipped over with an adhesive tape. The fine nano/microstructures on the Cu layer benefit the pressure-electric response of the pressure sensor, demonstrated a high sensitivity: 2.

Hierarchically Porous N-Doped Carbon Nanotubes/Reduced Graphene Oxide Composite for Promoting Flavin-Based Interfacial Electron Transfer in Microbial Fuel Cells.

Interfacial electron transfer between an electroactive biofilm and an electrode is a crucial step for microbial fuel cells (MFCs) and other bio-electrochemical systems. Here, a hierarchically porous nitrogen-doped carbon nanotubes (CNTs)/reduced graphene oxide (rGO) composite with polyaniline as the nitrogen source has been developed for the MFC anode. This composite possesses a nitrogen atom-doped surface for improved flavin redox reaction and a three-dimensional hierarchically porous structure for rich bacterial biofilm growth.

Efficient in situ growth of enzyme-inorganic hybrids on paper strips for the visual detection of glucose.

A visual colorimetric microfluidic paper-based analytical device (μPAD) was constructed following the direct synthesis of enzyme-inorganic hybrid nanomaterials on the paper matrix. An inorganic solution of MnSO and KHPO containing a diluted enzyme (glucose oxidase, GOx) was subsequently pipetted onto cellulose paper for the in situ growth of GOx@Mn(PO) hybrid functional materials. The characterization of the morphology and chemical composition validated the presence of hybrid materials roots in the paper fiber, while the Mn(PO) of the hybrid provided both a surface for enzyme anchoring and a higher peroxidase-like catalytic activity as compared to the Mn(PO) crystal that was synthesized without enzyme modulation.

Versatile microfluidic complement fixation test for disease biomarker detection.

The complement fixation test (CFT) is a serological test that can be used to detect the presence of specific antibodies or antigens to diagnose infections, particularly diseases caused by microbes that are not easily detected by standard culture methods. We report here, for the first time, a poly(dimethylsiloxane) (PDMS)/glass slide hybrid microfluidic device that was used to manipulate the solution compartment and communication within the microchannel to establish sampler and indicator systems of CFT. Two types of on-chip CFT, solution-based and solid phase agar-based assays, were successfully demonstrated for biomarker carcinoembryonic antigen (CEA) and recombinant avian influenza A (rH7N9) virus protein detection.

Combining complement fixation and luminol chemiluminescence for ultrasensitive detection of avian influenza A rH7N9.

The complement fixation test (CFT) is a serological test that can be used to detect the presence of either a specific antibody or antigen to diagnose infections. In a conventional CFT, the assay result is determined by observing the clarity of the reaction solution or the sediment of red cells by the naked eye. Although the assay conditions are thereafter simplified, the sensitivity of the assay would be sacrificed due to the limitation of bulk observation.