Label-free miRNA fluorescent biosensors based on duplex-specific nucleases and silver nanoclusters.

MicroRNAs (miRNAs) are considered reliable biomarkers for a variety of diseases. However, their low abundance in organisms and high sequence similarity of homologous miRNAs make their accurate detection challenging. Here, we constructed a novel fluorescent biosensor for the detection of miRNA-155, a potential biomarker of neuroinflammation, based on duplex-specific nuclease (DSN) assisted amplification and DNA-templated silver nanoclusters (DNA-AgNCs) as fluorescence signal probes.

Enhanced sensing of dinotefuran in foods based on BC/ZnCo MOF@PBA nano-enzyme induced MIECL sensor.

Natural enzymes can increase the signal of electrochemiluminescence. However, they are expensive and environmentally demanding. Here, the hollow prussian blue analogues decorated and biomass-derived carbon doped ZnCo metal-organic framework nano-enzyme was designed via self-assembly method.

Molten Salt-Assisted Synthesis of Ferric Oxide/M-N-C Nanosheet Electrocatalysts for Efficient Oxygen Reduction Reaction.

Efficient, stable, and low-cost oxygen reduction catalysts are the key to the large-scale application of metal-air batteries. Herein, high-dispersive FeO nanoparticles (NPs) with abundant oxygen vacancies uniformly are anchored on lignin-derived metal-nitrogen-carbon (M-N-C) hierarchical porous nanosheets as efficient oxygen reduction reaction (ORR) catalysts (FeO/M-N-C, M═Cu, Mn, W, Mo) based on a general and economical KCl molten salt-assisted method. The combination of Fe with the highly electronegative O induces charge redistribution through the Fe-O-M structure, thereby reducing the adsorption energy of oxygen-containing substances.

A modified Prussian blue biosensor with improved stability based on the use of self-assembled monolayers and polydopamine for quantitative L-glutamate detection.

A miniature L-glutamate (L-Glu) biosensor is described based on Prussian blue (PB) modification with improved stability by using self-assembled monolayers (SAMs) technology and polydopamine (PDA). A gold microelectrode (AuME) was immersed in NH(CH)SH-ethanol solution, forming well-defined SAMs via thiol-gold bonding chemistry which increased the number of deposited Prussian blue nanoparticles (PBNPs) and confined them tightly on the AuME surface. Then, dopamine solution was dropped onto the PBNPs surface and self-polymerized into PDA to protect the PB structure from destruction.

Self-Assembled Tetraphenylethene-Based Nanoaggregates with Tunable Electrochemiluminescence for the Ultrasensitive Detection of .

As an effective ECL emitter, tetraphenylethene (TPE)-based molecules have recently been reported with aggregation-induced electrochemiluminescence (AIECL) property, while it is still a big challenge to control its aggregation states and obtain uniform aggregates with intense ECL emission. In this study, we develop three TPE derivatives carrying a pyridinium group, an alkyl chain, and a quaternary ammonium group via the Menschutkin reaction. The resulting molecules exhibit significantly red-shifted FL and enhanced ECL emissions due to the tunable reduction of the energy gap between the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs).

Nanozyme-induced deep learning-assisted smartphone integrated colorimetric and fluorometric dual-mode for detection of tetracycline analogs.

In this work, a colorimetric and fluorescent dual-mode probe controlled by NH-MIL-88 B (Fe, Ni) nanozymes was developed to visually detect tetracycline antibiotics (TCs) residues quantitatively, as well as accurately distinguish the four most widely used tetracycline analogs (tetracycline (TC), chrycline (CTC), oxytetracycline (OTC), and doxycycline (DC)). Colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) may be oxidized to blue oxidized TMB by the Fe Fenton reaction, which was catalyzed by the NH-MIL-88 B (Fe, Ni) nanozyme with POD-like activity. The colorimetric detection system allows TCs to interact with NH-MIL-88 B (Fe, Ni).

Portable, intelligent MIECL sensing platform for ciprofloxacin detection using a fast convolutional neural networks-assisted Tb@LuO nanoemitter.

Environmental pollution caused by ciprofloxacin is a major problem of global public health. A machine learning-assisted portable smartphone-based visualized molecularly imprinted electrochemiluminescence (MIECL) sensor was developed for the highly selective and sensitive detection of ciprofloxacin (CFX) in food. To boost the efficiency of electrochemiluminescence (ECL), oxygen vacancies (OVs) enrichment was introduced into the flower-like Tb@LuO nanoemitter.

Sulfur vacancy defects mediated CdZnTeS@BC heterojunction: Artificial intelligence-assisted self-enhanced electrochemiluminescence molecularly imprinted sensing of CTC.

Environmental pollution caused by tetracycline antibiotics is a major concern of global public health. Here, a novel and portable molecularly imprinted electrochemiluminescence (MIECL) sensor based on smartphones for highly sensitive detection of chlortetracycline (CTC) has been successfully established. The high-performance ECL emitter of biomass carbon (BC) encapsulated CdZnTeS (CdZnTeS@BC) was successfully synthesized by hydrothermal.

Dual-channel MIRECL portable devices with impedance effect coupled smartphone and machine learning system for tyramine identification and quantification.

We designed a novel, portable, and visual dual-potential molecularly imprinted ratiometric electrochemiluminescence (MIRECL) sensor for tyramine (TYM) detection based on smartphone and deep learning-assisted optical devices. Molecularly imprinted polymer-CeSnO (MIP-CeSnO) layers were fabricated by in-situ electropolymerization method as the capture and signal amplification probe. Oxygen vacancies in CeSnO not only enhance the electrochemical redox capability but also accelerate the energy transfer, thereby enhancing the luminescence of cathode ECL.

Bimetallic MOF synergy molecularly imprinted ratiometric electrochemical sensor based on MXene decorated with polythionine for ultra-sensitive sensing of catechol.

Dual-signal ratiometric molecularly imprinted polymer (MIP) electrochemical sensors with bimetallic active sites and high-efficiency catalytic activity were fabricated for the sensing of catechol (CC) with high selectivity and sensitivity. The amino-functionalization bimetallic organic framework materials (Fe@Ti-MOF-NH), coupled with two-dimensional layered titanium carbide (MXene) co-modified glassy carbon electrode provides an expanded surface while amplifying the output signal through the electropolymerization immobilization of polythionine (pTHi) and MIP. The oxidation of CC and pTHi were presented as the response signal and the internal reference signal.

Deep learning-assisted smartphone-based portable and visual ratiometric fluorescence device integrated intelligent gel label for agro-food freshness detection.

Here, a smartphone-assisted dual-color ratiometric fluorescence smart gel label-based visual sensing platform was constructed for real-time evaluation of the freshness of agro-food based on the biogenic amines responses. Green-emission fluorescence carbon dots (CDs) coupled with blue-emission fluorescence bimetallic metal-organic framework (Fe/Zr-MOF) obtained dual-color CDs@Fe/Zr-MOF fluorescence nanoprobe acts as the response units. With the increase of SP and HIS content, the green fluorescence of CDs was enhanced, while the blue fluorescence of Fe/Zr-MOF was quenched.

Machine Learning System To Monitor Hg and Sulfide Using a Polychromatic Fluorescence-Colorimetric Paper Sensor.

An optical monitoring device combining a smartphone with a polychromatic ratiometric fluorescence-colorimetric paper sensor was developed to detect Hg and S in water and seafood. This monitoring included the detection of food deterioration and was made possible by processing the sensing data with a machine learning algorithm. The polychromatic fluorescence sensor was composed of blue fluorescent carbon quantum dots (CDs) (BU-CDs) and green and red fluorescent CdZnTe quantum dots (QDs) (named GN-QDs and RD-QDs, respectively).

Machine learning-assisted Te-CdS@MnO nano-enzyme induced self-enhanced molecularly imprinted ratiometric electrochemiluminescence sensor with smartphone for portable and visual monitoring of 2,4-D.

Here, a novel and portable machine learning-assisted smartphone-based visual molecularly imprinted ratiometric electrochemiluminescence (MIRECL) sensing platform was constructed for highly selective sensitive detection of 2,4-Dichlorophenoxyacetic acid (2,4-D) for the first time. Te doped CdS-coated MnO (Te-CdS@MnO) with catalase-like activity served as cathode-emitter, while luminol as anode luminophore accompanied HO as co-reactant, and Te-CdS@MnO decorated molecularly imprinted polymers (MIPs) as recognition unit, respectively. Molecular models were constructed and MIP band and binding energies were calculated to elucidate the luminescence mechanism and select the best functional monomers.

Electrochemical Oxidative C(sp)-H Amination of Aldehyde Hydrazones with Azoles.

A general and highly efficient method for the electrochemical C(sp)-H amination of aldehyde hydrazones with azoles has been developed. This reaction proceeds under exogenous metal-, catalyst-, and oxidant-free conditions to provide aminated hydrazone derivatives in good to excellent yields. This strategy applies to both aromatic and aliphatic aldehyde hydrazones and tolerates a broad range of functional groups.

Hollow nitrogen-doped carbon nanospheres as cathode catalysts to enhance oxygen reduction reaction in microbial fuel cells treating wastewater.

Hollow nanospheres play a pivotal role in the electro-catalytic oxygen reduction reaction (ORR), which is a crucial step in microbial fuel cell (MFC) device. Herein, the hollow nitrogen-doped carbon nanospheres (HNCNS) were synthesized with the sacrifice of silica coated carbon nanospheres (CNS@SiO) as template. HNCNS remarkably enhanced the ORR activity compared to the solid carbon and solid silica spheres.

Electrocatalytic, Kinetic, and Mechanism Insights into the Oxygen-Reduction Catalyzed Based on the Biomass-Derived FeO @N-Doped Porous Carbon Composites.

A valid strategy for amplifying the oxygen reduction reaction (ORR) efficiency of non-noble electrocatalyst in both alkaline and acid electrolytes by decorated with a layer of biomass derivative nitrogen-doped carbon (NPC) is proposed. Herein, a top-down strategy for the generally fabricating NPC matrix decorated with trace of metal oxides nanoparticles (FeO NPs) by a dual-template assisted high-temperature pyrolysis process is reported. A high-activity FeO /FeNC (namely Hemin/NPC-900) ORR electrocatalyst is prepared via simply carbonizing the admixture of Mg (OH) (CO ) and NaCl as dual-templates, melamine and acorn shells as nitrogen and carbon source, hemin as a natural iron and nitrogen source, respectively.

Enhancement of Mass Transport for Oxygen Reduction Reaction Using Petal-Like Porous Fe-NC Nanosheet.

Nitrogen-coordinated single-atom catalysts (SACs) have emerged as a new frontier for accelerating oxygen reduction reaction (ORR) owing to the optimal atom efficiency and fascinating properties. However, augmenting the full exposure of active sites is a crucial challenge in terms of simultaneously pursuing high metal loading of SACs. Here, petal-like porous carbon nanosheets with densely accessible Fe-N moieties (FeNC-D) are constructed by combining the space-confinement of silica and the coordination of diethylenetriaminepentaacetic acid.

Pt-poly(L-lactic acid) microelectrode-based microsensor for in situ glucose detection in sweat.

A miniaturized biosensor was developed for in situ noninvasive detection of glucose in sweat. The biosensor was composed of a pair of interdigital Pt-poly(L-lactic acid) (Pt-PLA) microelectrode arrays operating as the working and auxiliary electrode. The size of the sensor was 3.

Enhancing oxygen reduction reaction in air-cathode microbial fuel cells treating wastewater with cobalt and nitrogen co-doped ordered mesoporous carbon as cathode catalysts.

The sluggish oxygen reduction reaction (ORR) on the cathode severely limits the energy conversion efficiency of microbial fuel cells (MFCs). In this study, cobalt and nitrogen co-doped ordered mesoporous carbon (Co-N-OMC) was prepared by heat-treating a mixture of cobalt nitrate, melamine and ordered mesoporous carbon (OMC). The addition of cobalt nitrate remarkably improved the ORR reactivity, compared to the nitrogen-doped OMC catalyst.

Anodic Electrochemiluminescence of CdTe Quantum Dots Using Tripropylamine as Coreactant: Size-dependent Effect.

The quantum size effect of CdTe quantum dots (QDs) has been one of the targets of extensive research concerning the optical spectroscopy of semiconductors, but little is known about their effects on electrochemiluminescence (ECL) behavior, especially in the anodic potential range. In this present study, water-soluble CdTe QDs with different sizes were synthesized with a microwave-assisted hydrothermal method. Upon electrochemical oxidation of the CdTe QD in the presence of tri-n-propylamine (TPrA) as a coreactant, two ECL signals, called ECL and ECL, were observed at potentials corresponding to the oxidation of TPrA (at +0.

Enhancing oxygen reduction reaction by using metal-free nitrogen-doped carbon black as cathode catalysts in microbial fuel cells treating wastewater.

Microbial fuel cells (MFCs) is promising to combat environmental pollution by converting organic waste to electricity. One critical problem for practical application of MFCs treating wastewater is sluggish oxygen reduction reaction (ORR) on cathode. This study focused on developing novel metal-free cost-effective cathodic catalysts to enhance power generation of MFCs.

Bifunctional and highly sensitive electrochemical non-enzymatic glucose and hydrogen peroxide biosensor based on NiCoO nanoflowers decorated 3D nitrogen doped holey graphene hydrogel.

In this work, a simple strategy for fabricating a 3D nitrogen doped holey graphene hydrogel decorated with NiCoO nanoflowers (NHGH/NiCoO) via a one-pot hydrothermal method with subsequent calcination is reported for the first time. The novel NHGH/NiCoO nanocomposites featured high electrical conductivity, large and accessible surface areas, abundant active sites, and excellent electrocatalytic performance. Considering the excellent catalytic activity of NiCoO, a sensitive and bifunctional electrochemical non-enzymatic biosensor was established for the determination of glucose and hydrogen peroxide (HO).

Enzyme-free glucose sensor based on layer-by-layer electrodeposition of multilayer films of multi-walled carbon nanotubes and Cu-based metal framework modified glassy carbon electrode.

A high-performance nonenzymatic glucose sensor was successfully prepared by a layer by layer strategy through electrodeposition assembling multilayer films of Cu-metal-organic frameworks/multi-walled carbon nanotubes (Cu-MOF/MWNTs) modified glassy carbon electrodes (GCE). Different multilayer films of Cu-MOF/MWNTs modified GCE (Cu-MOF/MWNTs/GCE) were prepared by repeating the electrodeposition of MWNTs onto the GCE in an MWNTs solution (MWNTs/GCE) and electrodeposition of the Cu-MOF layer onto the MWNTs film surface to form a Cu-MOF/MWNTs composite layer in the crystallization solution of Cu-MOF. Results confirmed that this method to fabricate multilayer composite films on the GCE was fast and convenient, and that multilayer composite films were stable and unified.

A glassy carbon electrode modified with a bismuth film and laser etched graphene for simultaneous voltammetric sensing of Cd(II) and Pb(II).

Polyimide (PI) sheets were laser etched to obtain graphene-based carbon nanomaterials (LEGCNs). These were analyzed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy which confirmed the presence of stacked multilayer graphene nanosheets. Their large specific surface and large number of edge-plane active sites facilitate the accumulation of metal ions.

High-Voltage Flexible Microsupercapacitors Based on Laser-Induced Graphene.

High-voltage energy-storage devices are quite commonly needed for robots and dielectric elastomers. This paper presents a flexible high-voltage microsupercapacitor (MSC) with a planar in-series architecture for the first time based on laser-induced graphene. The high-voltage devices are capable of supplying output voltages ranging from a few to thousands of volts.