Hydrogel-based wound dressings are ideal materials as they could provide a moist environment to promote wound healing. Silk sericin is a natural macromolecular protein produced by silkworms and has positive effects on fibroblasts and keratinocytes. Sodium alginate is a natural polysaccharide known as a mouldable matrix. To develop novel hydrogel wound dressings, sodium alginate was functionalized with silk sericin to yield an injectable and mouldable semi-interpenetrating network hydrogel (SA/Se) using calcium ions as the crosslinking agents. Meanwhile, silver nanoparticles (AgNPs) were synthesized in situ by the phenolic hydroxyl group of tyrosine in sericin to enhance the antibacterial activity of the hybrid hydrogel. UV–visible spectroscopy, fluorescence spectroscopy, transmission electron microscope, X-ray photoelectron spectroscopy and energy dispersive spectroscopy demonstrated the successful synthesis of AgNPs with average size of 15.7 nm in SA/Se-Ag0.2. Field emission scanning electron microscopy showed the macroporous structure of the hydrogel. The hybrid hydrogel had a swelling ratio of 32 and more than 5% of retention ratio after 50 h. It exhibited effective antibacterial activity through irreversibly disrupting bacterial membrane structure to result in bacterial lysis and death. Cell counting kit-8 assay suggested the hybrid hydrogel was highly cytocompatible. The animal experiment showed the wound contraction ratio in SA/Se-Ag0.2 group was 99% after 12 days, indicating it can effectively promote wound healing. This novel hydrogel is promising for wound healing and tissue engineering.
Tremendous attention has been paid to the structure and properties of silk fibroin/sodium alginate (SF/SA) composite films . However, there is no report devoted to study the formation of hydrogen bonds and their effects on the structures and properties. Herein, SF/SA blends with different mass ratios were obtained and the technic of Gaussian multi-peaks-fitting of Fourier transform infrared spectrum (FTIR) was used to analyze their hydrogen bonds. From the results, the existence of the intermolecular and intramolecular hydrogen bonds was manifested, and the relative strength of the intermolecular hydrogen bond enhanced with the increase of SA content. The contribution of the intermolecular hydrogen bonding was as follows: OH⋯O (ether) > OH … π > OH⋯N. Meanwhile, the increase of intermolecular hydrogen bonding led to the increase of apparent viscosity of the SF/SA blend solutions. Moreover, the relationship between the hydrogen bond and properties (e.g, crystallinity , thermal stability, mechanical properties, morphology and etc.) of SF/SA composite films with different mass ratios were analyzed in detail.
Cong Cong Qin,Somia Yassin Hussain Abdalkarim,Ming Chen Yang,Yan Juan Dong,Hou-Yong Yu,Dan Ge
This work develops a sustainable and global strategy to enhance fruit preservation efficacy. The dual-use composite coating or film comprises silk fibroin/cellulose nanocrystals (SF/CNC) with superior ductility through a synergistic plasticizing effect of glycerol and natural aloe-emodin powder (AE) as antimicrobial agents. To confirm our strategy, two common fruit preservation materials (edible surface coating-SCA-CS; packaging film-SCA-PF) and five different fruits (strawberries, bananas, apples, blueberries, and guavas) have been used. Moreover, SCA-CS coating with antibacterial and antioxidant activities formed an ultrathin layer on the fruit's surfaces with a thickness of 7.7 μm and could be easily washable. Therefore, bananas and strawberries' shelf-life with SCA-CS coating can be extended for 9 days and 6 days, respectively. The discharge water of SCA-CS has excellent biosafety in an indoor environment with no threat to plant health (microgreens bean sprouts germination as a case study). The plant exhibited positive results within 15 days, and leaves maintained their green color with a germination rate of 97.6 %. The toughness of SCA-PF film increased by 14,685.7 % with a water vapor transmission rate (WPTR) of 17 g mm m −2 day −1 , which confirms that the concept of SCA-PF film and SCA-CS coating are feasible to be used for fruit preservation/packaging.
危险品化学品经营许可证（带存储）