Preparation and adsorption properties of magnetic chitosan/sludge biochar composites for removal of Cu2+ ions

The magnetic chitosan/sludge biochar composite adsorbent was prepared using chitosan, Fe3O4, and sludge biochar as raw materials. The composite adsorbent was able to achieve rapid solid-liquid separation under an applied magnetic field. The morphology and microstructure of the composite adsorbent were characterized by FTIR, XRD, SEM, VSM, and BET analysis. The adsorption performance of the composite adsorbent on Cu2+ was investigated through static adsorption experiments, and the effects of adsorbent dosage, initial concentration of Cu2+, initial pH of the solution, and adsorption temperature on the adsorption efficiency of Cu2+ were discussed. The results showed that chitosan and Fe3O4 were successfully loaded on sludge biochar. When the initial concentration of Cu2+ was 30 mg/L, the dosage of the magnetic chitosan/sludge biochar composite material was 0.05 g, the adsorption time was 180 min, pH was 5, and the temperature was room temperature, the maximum removal rate of Cu2+ reached 99.77%, and the maximum adsorption capacity was 55.16 mg/g. The adsorption kinetics and adsorption isotherm data fitted well with the pseudo-second-order kinetic model and Langmuir adsorption isotherm model, indicating that the adsorption process was chemisorption with monolayer coverage.

[Research advances on the role and mechanism of microRNA in hypertrophic scar]

Hypertrophic scar (HS) affects the function and beauty of patients, and brings a heavy psychological burden to patients. However, the specific pathogenesis mechanism of HS in molecular biology level is not yet clear, and this disease is still one of the clinical diseases difficult to prevent and cure. MicroRNA (miR) is a family of single-stranded endogenous noncoding RNAs that can regulate gene expression. The abnormal transcription of miR in hypertrophic scar fibroblasts can affect the transduction and expression of downstream signal pathway or protein, and the exploration of miR and its downstream signal pathway and protein helps deeply understand the occurrence and development mechanism of scar hyperplasia. This article summarized and analyzed how miR and multiple signal pathways involve in the formation and development of HS in recent years, and further outlined the interaction between miR and target genes in HS.

[Research advances on mesenchymal stem cell-derived extracellular vesicles in promoting angiogenesis of diabetic ulcers]

Extracellular vesicles are nanoparticles secreted by most eukaryotic cells and play important roles in material transport and information transmission between cells, involved in inflammation, angiogenesis, antigen presentation, cell apoptosis, cell differentiation, and other biological processes. The culture supernatant of mesenchymal stem cells is rich in extracellular vesicles, and the extracellular vesicles can regulate the formation of new blood vessels, a key step in wound healing and tissue repair. The persistence of diabetic ulcers is closely related to the blocked formation of wound vascular network. This article reviews the role of extracellular vesicles derived from mesenchymal stem cells in promoting angiogenesis of diabetic ulcers, in order to provide a new idea for the treatment of diabetic ulcers.

[Research advances on thymosin β4 in promoting wound healing]

With the aging of population and the development of social economy, the incidence of chronic wounds is increasing day by day, while the incidence of burns and trauma remains at a high level, making wound repair an increasingly concerned area in clinical practice. Thymosin β4 is a naturally occurring small molecule protein in vivo, which is widely distributed in a variety of body fluids and cells, especially in platelets. Thymosin β4 has biological activities of promoting angiogenesis, anti-inflammation, anti-apoptosis, and anti-fibrosis, and has many important functions in wound repair. Thymosin β4 has been observed to promote the healing of various wounds, such as burns, diabetic ulcers, pressure ulcers. This paper will review the molecular structure, mechanism of wound healing promotion, pharmacokinetics, and clinical application of thymosin β4, aiming to introduce its potential in wound treatment and the shortcomings of current researches.

[Research advances on the biomechanical micro- environment facilitated wound repair through the regulation of cell migration]

Biomechanical microenvironment refers to a variety of mechanical signals in the extracellular mechanical microenvironment, which will change correspondingly with time and space. It plays an important role in histological changes such as cell migration, proliferation, and differentiation, and can further affect wound healing. Wound healing is a complex pathophysiological process, and one of the important factors that affects wound healing is whether the cells can efficiently and quickly migrate to the wound center or not. Previous studies have shown that biomechanical microenvironment can not only induce the directional migration of cells, but also improve the migration rate of cells. In the complex natural environment, cells adopt various migration patterns and are dominated by special patterns such as local myosin contractility and extracellular microenvironment. In addition to overcoming the extracellular barrier, cells also need to interact with neighboring cells and tissue through local physical and mechanical forces and signals to complete migration and thus accelerate wound healing. Therefore, in recent years, scholars at home and abroad have been actively developing biological materials based on improving biomechanical microenvironment in order to further promote cell migration and thus accelerate wound healing. This paper reviews the recent research advances on the role of biomechanical environment in wound healing promotion via the regulating of cell migration and the development of related biomaterials.