The purpose of this study was to permit bone marrow mesenchymal stem cells (BMSCs) to reach their full potential in the treatment of chronic wounds. A biocompatible multifunctional crosslinker based temperature sensitive hydrogel was developed to deliver BMSCs, which improve the chronic inflammation microenvironments of wounds. A detailed in vitro investigation found that the hydrogel is suitable for BMSC encapsulation and can promote BMSC secretion of TGF-β1 and bFGF. In vivo, full-thickness skin defects were made on the backs of db/db mice to mimic diabetic ulcers. It was revealed that the hydrogel can inhibit pro-inflammatory M1 macrophage expression. After hydrogel association with BMSCs treated the wound, significantly greater wound contraction was observed in the hydrogel + BMSCs group. Histology and immunohistochemistry results confirmed that this treatment contributed to the rapid healing of diabetic skin wounds by promoting granulation tissue formation, angiogenesis, extracellular matrix secretion, wound contraction, and re-epithelialization. These results show that a hydrogel laden with BMSCs may be a promising therapeutic strategy for the management of diabetic ulcers.

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In the past decades, various alternating current electroluminescent (ACEL) devices, especially the flexible ones, have been developed and used in flat panel display, large-scale decorating, logo display lighting, optical signaling, etc. Transparent plastics are usually used as substrates in ACEL devices; however, they are undegradable and may cause serious environmental pollution. Herein, we have developed a flexible transient ACEL device based on transparent fish gelatin (FG) films. The FG films were made from fish scales, which are sustainable, cost-efficient, and eco-friendly. These films could dissolve in water within seconds at 60 °C and degrade completely within 24 days in soil. The transmittance of these FG films was up to 91.1% in the visible spectrum, comparable to that of polyethylene terephthalate (PET) (90.4%). After forming a composite with silver nanowires (Ag NWs), the Ag NWs-FG film showed a transmittance up to 82.3% and a sheet resistance down to 22.4 Ω sq–1. The fabricated ACEL device based on the Ag NWs-FG film exhibited high flexibility and luminance up to 56.0 cd m–2. The device could be dissolved in water within 3 min. Our work demonstrates that the sustainable, flexible, and transparent FG films are a promising alternative for green and degradable substrates in the field of flexible electronics, including foldable displays, wearable devices, and health monitoring.

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Brown carbon (BrC), an aerosol carbonaceous matter component, impacts atmospheric radiation and global climate because of its absorption in the near-ultraviolet−visible region. Simultaneous air sampling was conducted in two megacities of Xi'an (northern) and Hong Kong (southern) in China in winter of 2016−2017. The aim of this study is to determine and characterize the BrC compounds in collected filter samples. Characteristic absorption peaks corresponding to aromatic C−C stretching bands, organo-nitrates, and CO functional groups were seen in spectra of Xi'an samples, suggesting that the BrC was derived from freshly smoldering biomass and coal combustion as well as aqueous formation of anthropogenic secondary organic carbon. In Hong Kong, the light absorption of secondary BrC accounted for 76% of the total absorbances of BrC. The high abundance of strong CO groups, biogenic volatile organic compounds (BVOCs) and atmospheric oxidants suggest secondary BrC was likely formed from photochemical oxidation of BVOCs in Hong Kong. Several representative BrC molecular markers were detected using Fourier transform ion cyclotron resonance mass spectrometry and their absorption properties were simulated by quantum chemistry. The results demonstrate that light absorption capacities of secondary anthropogenic BrC with nitro-functional groups were stronger than those of biogenic secondary BrC and anthropogenic primary BrC.

Skin wound healing is a complicated process that involves a variety of cells and cytokines. Fibroblasts play an important role in this process and participate in transformation into myofibroblasts, the synthesis of extracellular matrix (ECM) and fibers, and the secretion of a variety of growth factors. This study assessed the effects of peptide Ser-Ile-Lys-Val-Ala-Val (SIKVAV)--modified chitosan hydrogels on skin wound healing. We investigated the capability of peptide SIKVAV to promote cell proliferation and migration, the synthesis of collagen, and the secretion of a variety of growth factors using fibroblasts in vitro. We also treated skin wounds established in mice using peptide SIKVAV-modified chitosan hydrogels. Hematoxylin and eosin staining showed that peptide-modified chitosan hydrogels enhanced the reepithelialization of wounds compared with negative and positive controls. Masson’s trichrome staining demonstrated that more collagen fibers were deposited in the wounds treated with peptide-modified chitosan hydrogels compared with the negative and positive controls. Immunohistochemistry revealed that the peptide-modified chitosan hydrogels promoted angiogenesis in the skin wound. Taken together, these results suggest that peptide SIKVAV-modified chitosan hydrogels may be useful in wound dressing and the treatment of skin wounds.