A Nanoporous Graphene/Nitrocellulose Membrane Beneficial to Wound Healing

In situ forming double-crosslinked hydrogels with highly dispersed short fibers for the treatment of irregular wounds

In situ forming injectable hydrogels hold great potential for the treatment of irregular wounds. However, their practical applications were hindered by long gelation time, poor mechanical performance, and a lack of a natural extracellular matrix structure. Herein, amino-modified electrospun poly(lactic-co-glycolic acid) (APLGA) short fibers with uniform distribution were introduced into gelatin methacrylate/oxidized dextran (GM/ODex) hydrogels. In comparison with the fiber aggregation structure in the PLGA fiber-incorporated hydrogels, the hydrogels with APLGA fibers possessed a uniform porous structure. The highly dispersed APLGA short fibers accelerated the sol-gel phase transition of the hydrogel due to the formation of dynamic Schiff-base bonds between the fibers and hydrogels. Furthermore, in combination with UV-assisted crosslinking, a rapid gelation time of 90 s was achieved for the double-crosslinked hydrogels. The addition of APLGA short fibers as fillers and the formation of the double-crosslinking network enhanced the mechanical performance of the hydrogels. Furthermore, the fiber-hydrogel composites exhibited favorable injectability, excellent biocompatibility, and improved cell infiltration. In vivo assessment indicated that the GM/ODex-APLGA hydrogels successfully filled the full-thickness defects and improved wound healing. This work demonstrates a promising solution for the treatment of irregular wounds.

Green- and Red-Emitting Fluorescent Silicon Nanoparticles: Synthesis, Mechanism, and Acid Phosphatase Sensing

Until now, the green and facile synthesis of multicolor fluorescent silicon nanoparticles (SiNPs) with favorable biocompatibility for cellular imaging and biosensors is still a challenge. Herein, a facile one-step room temperature method for preparing fluorescent SiNPs displayed different emission wavelengths was reported. Green and red fluorescent SiNPs (G-SiNPs and R-SiNPs) were synthesized by adjusting the concentration of the reducing agent 2,4-diaminophenol hydrochloride when the amount of N-[3-(trimethoxysilyl)-propyl]-ethylenediamine was consistent. Characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, the results revealed that the G-SiNPs and R-SiNPs were assembled by polymerization of different building blocks, and the emission characteristics of these SiNPs were attributed to the difference in their structural composition and particle size. Interestingly, these fluorescent SiNPs exhibited excellent water solubility, salt tolerance, pH stability, photobleaching resistance, and low cytotoxicity, which facilitated multicolor cell imaging, and further led to these SiNPs were highly attractive in a variety of applications, such as multi-channel sensing and biological imaging. Furthermore, the R-SiNPs have shown the potential to detect acid phosphatase, which is a biomarker of prostate cancer.

Graphene- and Nanoparticle-Embedded Antimicrobial and Biocompatible Cotton/Silk Fabrics for Protective Clothing

Protection against pathogens using personal protective equipment is essential yet challenging in healthcare settings. Concerns over emerging biothreats and outbreaks of infectious diseases underscore the need for antimicrobial and biocompatible protective clothing to protect patients and staff. Herein, we report the antimicrobial efficacy and cytotoxicity of cotton/silk fabrics containing embedded reduced graphene oxide (RGO) and Ag/Cu nanoparticles (NPs), prepared using a 3-glycidyloxypropyl trimethoxy silane coupling agent followed by chemical reduction and vacuum heat treatment. Embedding NPs on top of the RGO layer substantially increased the antimicrobial activity. All RGO-Ag NPs or RGO-Cu NPs embedded in cotton or silk fabrics reduced the viability of approximately 99% of the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. RGO-Ag NPs embedded into cotton or silk fabrics reduced the viability of the Gram-positive bacterium Staphylococcus aureus by 78-99%, which was higher than the growth inhibition by RGO-Cu NPs samples against S. aureus. Both silk and cotton containing RGO-Cu NPs produced a greater reduction in the viability of the yeast Candida albicans compared to RGO-Ag NPs fabrics. All RGO-Ag NPs or RGO-Cu NPs embedded in cotton or silk fabrics showed good washing durability by sustaining good bactericidal activity, even on washing up to 10 times. Moreover, none of the RGO-Ag or RGO-Cu fabrics reduced mammalian cells' (HEK293) viability by >30%, suggesting low cytotoxicity and good biocompatibility. These findings show that RGO-NPs embedded in cotton or silk fabrics have great potential for use in protective clothing and medical textiles.