Wound dressings composed of natural polymers, such as type I collagen, possess good biocompatibility, water holding capacity, air permeability, and degradability, and can be used in wound repair. However, due to the persistent oxidative stress in the wound area, the migration and proliferation of fibroblasts might be suppressed, leading to poor healing. Thus, collagen-containing scaffolds are not suitable for accelerated wound healing. Antioxidant N-acetyl cysteine (NAC) is known to reduce the reactive oxygen species (ROS) and has been widely used in the clinic. Theoretically, the carboxyl group of NAC allows loading of graphene oxide (GO) for sustained release and may also enhance the mechanical properties of the collagen scaffold, making it a better wound-dressing material. Herein, we demonstrated an innovative approach for a potential skin-regenerating hybrid membrane using GO incorporated with collagen I and NAC (N-Col-GO) capable of continuously releasing antioxidant NAC.

Liposomes are ubiquitous tools in biomedical applications, such as drug delivery, membrane science and artificial cell. Micro- and nanofabrication techniques have revolutionized the preparation of liposomes on the microscale. State-of-the-art liposomal formation on microfluidic chips and its associated applications are introduced in this review. We attempt to provide a reference for liposomal researchers by comparing various microfluidic techniques for liposomes formation.

Background: The efficacy of autologous fat transplantation is reduced by fat absorption and fibrosis that are closely related to unsatisfactory vascularization. Extracellular vesicles are key components of the cell secretome, which can mirror the functional and molecular characteristics of their parental cells. Growing evidence has revealed that adipose-derived mesenchymal stem cells have the ability to enhance vascularization, which is partly ascribed to extracellular vesicles. The authors evaluated whether adipose-derived mesenchymal stem cell–derived extracellular vesicles improved vascularization of fat grafts and increased their retention rate. Methods: To test the angiogenesis ability of adipose-derived mesenchymal stem cell–derived extracellular vesicles, they were isolated from the supernatant of cultured human adipose-derived mesenchymal stem cells and incubated with human umbilical vein endothelial cells in vitro. Then, the vesicles were co-transplanted with fat into nude mice subcutaneously. Three months after transplantation, the retention rate and inflammatory reaction of the grafts were analyzed by histologic assay. Results: The experimental group could significantly promote migration and tube formation at the concentration of 20 μg/ml. At 3 months after transplantation, the volume of the experimental group (0.12 ± 0.03 mm³) was larger compared with the blank group (0.05 ± 0.01 mm³). Histology and immunohistology results demonstrated significantly fewer cysts and vacuoles, less fibrosis, and more neovessels in the extracelluar vesicle group. Conclusions: The authors co-transplanted adipose-derived mesenchymal stem cell–derived extracellular vesicles with fat into a nude mouse model and found that the vesicles improved volume retention by enhancing vascularization and regulating the inflammatory response.