A novel electrochemical exfoliation mode was established to prepare graphene sheets efficiently with potential applications in transparent conductive films. The graphite electrode was coated with paraffin to keep the electrochemical exfoliation in confined space in the presence of concentrated sodium hydroxide as the electrolyte, yielding ∼100% low-defect (the D band to G band intensity ratio, I/I = 0.26) graphene sheets. Furthermore, ozone was first detected with ozone test strips, and the effect of ozone on the exfoliation of graphite foil and the microstructure of the as-prepared graphene sheets was investigated. Findings indicate that upon applying a low voltage (3 V) on the graphite foil partially coated with paraffin wax that the coating can prevent the insufficiently intercalated graphite sheets from prematurely peeling off from the graphite electrode thereby affording few-layer (<5 layers) holey graphene sheets in a yield of as much as 60%. Besides, the ozone generated during the electrochemical exfoliation process plays a crucial role in the exfoliation of graphite, and the amount of defect in the as-prepared graphene sheets is dependent on electrolytic potential and electrode distance. Moreover, the graphene-based transparent conductive films prepared by simple modified vacuum filtration exhibit an excellent transparency and a low sheet resistance after being treated with NHNO and annealing (∼1.21 kΩ/□ at ∼72.4% transmittance).

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The solubility of form A metformin hydrochloride (MET·HCl) in water, methanol, ethanol, water + methanol, water + ethanol, water + acetone, and water + isopropanol at the temperatures ranging from 283.15 to 323.15 K was determined by gravimetric method. The experimental results show that the solubility increases with the increase of temperature and the initial water content of the binary solvents. The order of solubility in the four aqueous solvent mixtures is water + methanol > water + ethanol > water + isopropanol > water + acetone, which is mainly contributed by the hydrogen bond interactions. The modified Apelblat model, CNIBS/R–K model, and Apelblat–Jouyban–Acree model were used to correlate the solubility data. The results show that the Apelblat model can correlate the solubility of four binary solvents best, and all average relative deviations are less than 6%.

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Catalpol, a natural active ingredient extracted from the traditional Chinese medicine, was verified exhibiting beneficial effects on neural differentiation compared with commonly used chemical inducers by our previous studies. The aim of this study was to evaluate the effects of catalpol-loaded scaffold on guiding neuronal differentiation of human adipose tissue-derived stem cells (hASCs). Fabrication technique of catalpol loading into the electrospun poly(lactic-co-glycolic acid)/multi-walled carbon nanotubes/silk fibroin nanofibrous scaffolds was successfully established. The topographical and mechanical properties of the nanofibers scaffolds were characterized by scanning electron microscopy and tensile instrument, respectively. In vitro catalpol release was studied in phosphate-buffered solution at 37 °C. Immunnocytochemistry, RT-PCR, and western blot assays were performed to estimate hASCs neuronal differentiation, and it was shown that catalpol has significantly upregulated the expressions of βIII-tubulin and Nissl. Our experiments demonstrated that catalpol, as a traditional Chinese medicine extract, could be encapsulated into composite nanofibers and induce differentiation of hASCs into neural-like cells, which might offer new avenues in nerve regeneration.