Janus hydrogel with dual antibacterial and angiogenesis functions for enhanced diabetic wound healing

Anti-infection and neovascularization at the wound site are two vital factors that accelerate diabetic wound healing. However, for a wound healing dressing, the two functions need to work at different sites(inner and outer), giving big challenges for dressing design. In this study, we fabricated a novel sodium alginate/chitosan(SA/CS) Janus hydrogel dressing by the assembly of SA hydrogel loaded with silver nanoparticles(Ag NPs) and CS hydrogel impregnated with L-arginine loaded sodium alginate microspheres(Arg MSs) based on electrostatic interactions to combine the two functions. The outer SA-Ag NP hydrogel could prevent infection while avoiding the deposition of Ag NPs in the wound site, and the inner CS-Arg MS hydrogel on the wound surface could realize the sustained release of L-arginine and promote vascular regeneration. The composition, morphology and swelling/degradation of the SA-Ag NP/CS-Arg MS hydrogel were characterized systematically. L-Arginine release behavior has been tested and SA-Ag NP/CSArg MS hydrogel has been confirmed for excellent biocompatibility. Antibacterial and angiogenesis assays demonstrated the antibacterial and angiogenesis characteristics of the SA-Ag NP/CS-Arg MS hydrogel. Finally, in vivo diabetic wound healing assay demonstrated that the SA-Ag NP/CS-Arg MS hydrogel could significantly accelerate re-epithelialization, granulation tissue formation, collagen deposition and angiogenesis, thereby resulting in enhanced diabetic wound healing。

Injectable baicalin/F127 hydrogel with antioxidant activity for enhanced wound healing

Baicalin,extracted from traditional Chinese medicine Scutellaria baicalensis Georg,possesses multiple pharmacological activities and has great potential for chronic skin wound repair.However,the poor solubility and lack of suitable vehicles greatly limit its further application.Herein,we proposed a convenient and robust strategy,employing PBS solution as solvent,to enhance the solubility of baicalin.Furthermore,we constructed injectable baicalin/F127 hydrogels to study their application in skin wound treatment.The composition and temperature sensitivity of baicalin/Pluronic®F-127 hydrogels were confirmed by FTIR and rheological testing,respectively.In vitro release measurement indicated that the first order model was best fitted with the release profile of baicalin from hydrogel matrix.Besides,MTT assay,AO/EO staining assay as well as hemolytic activity test revealed the excellent cytocompatibility of baicalin/F127 hydrogels.Antioxidant activity assay demonstrated the cytoprotective activity of baicalin/F127 hydrogels against reactive oxygen species(ROS).Furthermore,the in vivo experiments exhibited the ability of baicalin/F127 hydrogel to accelerate wound healing.In conclusion,this novel injectable baicalin/F127 hydrogel should have bright application for chronic wound treatment.

Progress on intelligent hydrogels based on RAFT polymerization:Design strategy, fabrication and the applications for controlled drug delivery

Although intelligent hydrogels have shown bright potential application in biomedical fields,they were prepared by conventional methods and still face many serious challenges,such as uncontrollable stimulus-response and low response sensitivity.Recently,RAFT polymerization provides a versatile strategy for the fabrication of intelligent hydrogels with improved stimulus-response properties,owing to the ability to efficiently construct hydrogel precursors with well-defined structure,such as block copolymer,graft copolymer,star copolymer.In this review,we summarized the recent progress on intelligent hydrogels based on RAFT polymerization with emphasis on their fabrication strategies and applications for controlled drug delivery.