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A sensitive mercury-free lead (Pb 2þ ) sensor has been proposed based on an ordered mesoporous carbon and Nafion composite film (OMC/Nafion) coated glassy carbon electrode. The analysis of Pb 2þ using anodic stripping voltammetry (ASV) includes two steps. Pb 2þ ions are firstly reduced and deposited on the electrode surface in a Pb 2þ solution (10 mL) during a preconcentration step biased at À 1.0 V, followed by a measurement step by differential pulse voltammetry (DPV) within the potential range of À 0.8 to À 0.3 V (scan rate: 20 mV/s, frequency: 20 Hz, amplitude: 50 mV, pulse width: 50 ms). Linear calibration curve was found to be from 20 nM to 2 mM for Pb 2þ with a sensitivity of 17.4 AE 1.38 mA/mM after a 5-min of preconcentration. The detection limit was estimated to be around 4.60 AE 0.12 nM at the signal to noise ratio of 3. Reproducibility (RSD%) was found to be 3.0% for a single sensor with eight measurements and 4.3% for five sensors prepared with identical procedures. The practical application of the proposed lead sensor was verified by determination of trace level of Pb 2þ in tap water sample.

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The harsh urine microenvironment (UME), as an inherent hurdle, endangers and renders urethral repair unreachable. Innovatively, the unfavorable UME is utilized as the design source to construct a UME‐responsive 3D‐printed hydrogel patch for realizing scarless memory repair, wherein laser‐excited reactive oxygen species (ROS) production and mechanical strength elevation using chemically crosslinked silicon quantum dots are accessible. Intriguingly, the proposed composite scaffolds can respond to Ca2+ in urine, cause structure reconfiguration, and repress swelling to further enhance scaffold stiffness. Systematic experiments validate that ROS birth and unexpected stiffness elevation in such UME‐responsive scaffolds can realize scarless memory repair of the urethra in vivo. Comprehensive mechanism explorations uncover that the activations of cell proliferation and collagen‐related genes (e.g., MMP‐1 and COL3A1) and the dampening of fibrosis‐related (e.g., TGF‐β/Smad) and mechanosensitive genes (e.g., YAP/TAZ) are responsible for the scarless memory repair of such UME‐responsive scaffolds via enhancing collagen deposition, recalling mechanical memory, decreasing fibrosis and inflammation, and accelerating angiogenesis. The design rationales (e.g., UME‐initiated structure reconfiguration and antiswelling) can serve as an instructive and general approach for urethra repair.

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Surface renewable ordered mesoporous carbon paste electrodes (OMCPE) were prepared by mechanical mixing ordered mesoporous carbon (OMC) and mineral oil. Electrochemical behavior of the composite electrode was evaluated and compared with the conventional graphite paste (GPE) and carbon nanotubes paste (CNTPE) electrodes. The OMCPE provided improved electron transfer kinetics and catalytic capabilities in connection with oxidation and/or reduction of different redox systems, such as ferricyanide and some biological species, e. g. ascorbic acid (AA), uric acid (UA), b-nicotinamide adenine dinucleotide (NADH), dopamine (DA), epinephrine (EP), acetaminophenol (AP) and hydrogen peroxide. The substantial decrease in the over voltage of the hydrogen peroxide oxidation along with the facile incorporation of glucose oxidase (GOD) into the composite matrix allowed us successfully to fabricate a sensitive and selective glucose biosensor. A linear response up to 15 mM glucose was obtained for the OMCPE modified with 10% GOD (w/w) with a detection limit of 0.072 mM. In addition, we also successfully applied the OMCPE to the anodic stripping voltammetric analysis of heavy metal ions with improved sensitivities in comparison with CNTPE and GPE. The excellent experimental results implicate that the new developed paste electrode holds great promise in the design of electrochemical devices, such as sensors and biosensors.

Electrospun composite fluorescent sensors for selective discrimination of nitro explosives and trace water were developed.