Peixin Li,Yanfang Sun,Lei Nie,Amin Shavandi,Khaydar E. Yunusov,Yinjian Hua,Guohua Jiang
Androgenetic alopecia (AGA) is a transracial and cross-gender disease worldwide with a higher prevalence among young individuals. Traditional oral or subcutaneous injections are often used to treat AGA, however, they may cause severe side-effects and therefore effective treatments for AGA are currently lacking. In this work, to treat AGA, we developed a composite paste system based on minoxidil (MXD)-loaded nanoparticles and valproic acid (VPA) with the assistance of roller-microneedles (roller-MNs). The matrix of composite paste systems is carboxymethyl cellulose (CMC), hyaluronic acid (HA) and polyvinylpyrrolidone (PVP). The roller-MNs can create microchannels in the skin to enhance drug transdermal efficiency. With the combined effects of the stimulation hair follicle (HF) regrowth by upregulating Wnt/beta-catenin of VPA and the mechanical microchannels induced by roller-MNs, the as-prepared composite paste systems successfully boost perifollicular vascularization, and activate hair follicle stem cells, thereby inducing notably faster hair regeneration at a lower administration frequency on AGA mouse model compared with minoxidil. This approach offers several benefits, including the avoidance of efficacy loss due to the liver's first-pass effect associated with oral drug, reduction in the risk of infection from subcutaneous injection, and significant decrease in the side effects of lower-dose MXD.
Xi Chen,Yu Zhang,Yue Qiao,Enmao Zhang,Wenqi Zhao,Xigao Jian,Cheng Liu
Carbon fiber-reinforced high-performance thermoplastic polymer (CFRHPTP) composites are highly susceptible to interlaminar damage when are subjected to external damage, which affects their mechanical properties and structural integrity. In this study, a core–shell electrospun fiber with partially exposed carbon nanotubes (CNTs) on the shell layer was prepared by coaxial electrostatic spinning of polyimide/polyvinylpyrrolidone (PI/PVP) core–shell fiber veils containing CNTs, and then was gradually etched until the CNTs embedded in the shell layer of the fibers were as gradually exposed. The introduction of core–shell veils with micro–nanostructures into the interlayers of carbon fiber-reinforced poly(phthalazinone ether sulfone ketone) (CF/PPESK) composites enhanced their interlayer and in-plane properties. The initial and propagation values of the composite’s mode I interlaminar fracture toughness were increased to 1182 J/m 2 and 1266 J/m 2 (46 % and 39 % increases, respectively), and the mode II interlaminar fracture toughness was improved to 2091 J/m 2 (113 % increase) after the introduction of electrospun veils into the interlayers. In addition, the tensile strength, flexural strength, and interlaminar shear strength of the CF/PPESK composites were enhanced by 17 %, 20 %, and 18 %, respectively. Molecular dynamics simulations elucidated the positive effect of PVP for an enhanced interface between the spun fiber and resin. Simultaneous increases in toughness and strength of the CF/PPESK composites were achieved. This study provides new ideas and methods for synergistic reinforcement and toughening of CFRHPTP composites through interlayer design of high-performance composites.
A novel method for the determination of aflatoxins B1, B2, G1, and G2 (AFB1, AFB2, AFG1, AFG2) in animal feed samples based on magnetic solid-phase cleanup and novel pre-column derivatization has been developed. In this work, synthesized polyvinylpyrrolidone-coated Fe3O4 magnetic nanoparticles were applied as adsorbents for rapid cleanup for extracts of animal feed samples. The purified extract was then derivatized with trifluoroacetic acid coupling ultraviolet irradiation which enabled the weakly fluorescent AFB1 and AFG1 transformed into their highly fluorescent hemiacetals derivatives. Afterward aflatoxins were separated and quantified by reverse phase liquid chromatography with fluorescence detection. The results indicated that four AFs presented excellent linear response with correlation coefficients > 0.996 and recoveries ranged from 86.7 to 108.9% with relative standard deviations (RSDs) from 3.6 to 6.4%. The limits of detection (LODs) were 0.0392, 0.2429, 0.0842, 0.4556 ng mL-1 for AFB1, AFB2, AFG1 and AFG2, respectively.
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