Two-dimensional boron nitride quantum dots (2D BNQDs) with excellent chemical stability, high photoluminescence efficiency, and low toxicity are a new class of advanced materials for biosensing and bioimaging applications. To overcome the current challenge about the lack of facile, scalable, and reproducible synthesis approach of BNQDs, we introduce a green and facile approach based on mechanochemical exfoliation of bulk h-BN particles in ethanol. Few-layered hydroxylated-functionalized QDs with a thickness of 1-2 nm and a lateral dimension of 2-6 nm have been prepared. The synthesized nanocrystals exhibit a strong fluorescence emission at 407 and 425 nm with a quantum efficiency of ∼6.2%. Spectroscopic analyses determine that interactions between oxygen groups of the solvent with boron sites occur, which along with the mechanical forces, lead to efficient exfoliation of the hexagonal structure and surface functionalization with -OH groups. We also demonstrate that the orbital interaction between BNQDs and the gold surface results in a profound electrochemical catalytic activity toward oxidation of vitamin C. It is shown that the BNQD-modified screen-printed gold electrode exhibits a decreased onset oxidation potential for about 0.37 V/AgCl. In addition to high catalytic activity, electrochemical studies also reveal that this electrode allows selective and sensitive detection of vitamin C with a good response over a wide range from 0.80 μM to 5.0 mM with a detection limit of 0.45 μM (S/N = 3) and a sensitivity of 1.3 μA μM cm. Finally, the potential application of the hybrid sensor for detecting vitamin C in commercial drinks is demonstrated.

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Polymer‐based composites are used for wound healing applications. This work aims to prepare an inorganic‐polymer nanocomposite based on bentonite, poly(vinyl alcohol), and bacterial cellulose by electrospinning for wound healing. The nanocomposite is synthesized using a solution intercalation technique, with 1–2 wt% nanobentonite concentration variation. The effects of commercial and laboratory‐synthesized nanobentonite as well as the extract of the green walnut shell (EGWS) are examined and characterized by different techniques. The addition of nanobentonite increases the average size of fibers and tensile strength up to 200 nm and more than 15 MPa, respectively, due to the presence of hydrogen bonding formed between the nanobentonite sheets and polymer matrix. By the addition of synthetic nanoclay and EGWS, moderate elongation and strength are achieved. The hydrophilicity shows a decreasing trend up to 2 wt% of commercial nanobentonite; however, the laboratory‐synthesized nanobentonite is not significantly effective. Effects of extracts on the viability of cultured human adipose tissue–derived mesenchymal stem cells (ADSCs) are quantitated, where the samples containing 1–2 wt% of commercial nanobentonite have less toxicity than others. Antibacterial activity is tested against both Escherichia coli and Staphylococcus aureus bacteria according to the agar diffusion test for 72 h, in which EGWS‐based mats exhibit strong antimicrobial activity.

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For the rapid detection of hyperglycemia in human blood, we adopted a facile and two-step electrochemical procedure to prepare nickel/reduced graphene oxide (rGO) hybrid electrodes in the framework of a three-dimensional (3D) nanostructure. High-density and vertically-aligned nickel submicrorods with an average diameter of 155 ± 15 nm and a length of 7 ± 1 μm (an aspect ratio of about 40–50) were prepared by template-mediated electrochemical deposition techniques. Networks of rGO nanosheets between the rod-shaped arrays were formed by the cathodic electrophoretic deposition method. The synergistic effect of nickel morphology (planar and high-density rod-shaped arrays) and graphene oxide nanosheets on the electrochemical glucose oxidation in both simulated and real samples (human blood serum) were studied. It is shown that the higher surface area of Ni submicrorods significantly enhances the sensitivity of glucose detection by 6-fold (659.5 μA mM−1 cm−2) as compared with planar Ni (113 μA mM−1 cm−2) while the limit of detection (LOD at S/N = 3) is reduced by ∼62% (from 0.13 mM to 0.05 mM). In the presence of reduced graphene oxide nanosheets, enhanced surface contacts between the metal submicrorods and the carbon nanostructure facilitate electron transfer through surface OH− motifs, further improving the sensitivity to 7121 μA mM−1 cm−2. A better LOD (0.5 μM) is also attained. The application of the electrode for glucose detection in human blood serum, i.e., fast detection (<3 s) with relatively high precision (94% confidence), is demonstrated.

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This study aims to produce smart nanocomposite fibers using the electrospinning method for potential sensing applications. For this purpose, polyvinylpyrrolidone (PVP) and polydiacetylene (PDA) solutions at two different ratios are prepared and electrospun at the voltage of 15 kV, distance to the collector of 15 cm, and the flow rate of 1 mL/h. To enhance the mechanical properties and sensitivity of the fibers, graphene oxide (GO) is then added to the polymer solution at different percentages of 0.5 to 2 wt%, and electrospinning is performed under the optimized conditions. Based on SEM analysis, with increasing the percentage of GO, the average fiber diameter decreases from 180 nm (without graphene) to 150 nm (1.5 wt% GO) due to the higher conductivity of the polymer solution after incorporation of GO. FTIR spectra reveal the possible hydrogen bonding between the components. In order to investigate the colorimetric behavior of the electrospun nanofibers, they are subjected to various temperatures and pHs, and a color change from bluish‐purple to reddish‐pink is observed due to conformational changes in PDA macromolecules. Finally, DSC results confirm the higher thermal stability of the nanocomposite fibers containing GO. Therefore, the fabricated thermochromic nanofibers are potentially appropriate candidates as sensors.