Study On Composite Hydrogels For Tissue Repair

The skin is the first line of defense for human immunity and is most vulnerable to damage.Healing of the skin wound is a complex and orderly process that involves different stages of repair.Once a disorder occurs,scars often form in the injured area,and even develop into Chronic wounds are difficult to heal and cause infection.According to reports,more than 80% of bacterial infections are caused by bacterial biofilms.Once established,bacterial biofilms have a high resistance to various antibiotics and are extremely difficult to eradicate.Due to their unique physical and chemical properties,gold nanoparticles,as antibacterial materials,exhibit good antibacterial effects in vivo and in vitro,with a broad antibacterial spectrum,diverse antibacterial mechanisms,and good application prospects.At the same time,antibacterial peptides can quickly resist pathogens such as bacteria and fungi.The target is mainly a bacterial cell membrane,which is not prone to drug resistance,and can be used as a substitute for antibiotics.Recell technology can collect autologous skin cells to promote skin wound repair.The operation is simple and fast,and it has a good repair effect on large areas of damaged skin.Short peptide hydrogels can self-assemble to form extracellular matrix due to the amphiphilic structure.The polymer nanofiber network captures a large amount of water,which is conducive to cell migration and proliferation and can serve as a barrier to prevent wound wear and provide a good microenvironment for wound repair.Based on the above,this article has designed two parts,the study of the antibacterial performance of antibacterial agents and the application of skin tissue repair.The details are as follows:First part: firstly synthesize gold nanoparticles protected by sodium citrate and polydentate thiol zwitterionic ligand di-LA-PC,and obtain di-LA-PC modified gold nanoparticles(AuNPs-di-LA-PC).The ligand modification was confirmed by EDS,IR,NMR,etc.;its stability was evaluated by UV-visible spectroscopy.The results show that AuNPs-di-LA-PC is stable at acid,base,salt,protein,high temperature,The stability under DTT and other conditions is high,and the TEM picture shows that the nanoparticles have good dispersibility;the antibacterial performance is evaluated by the turbidity method and the flat coating method,but the antibacterial performance of AuNPs-di-LA-PC is not outstanding.In order to further improve the antibacterial activity of the composite hydrogel,an N-terminally modified lipoic acid octapeptide(LA-Bac8c)was obtained by a solid-phase synthesis method,and the structure of the product was confirmed by MS and HPLC.Bac8 c before and after LA modification was evaluated,and the antibacterial effect of LA-Bac8 c on Sa and MRSA was improved by turbidity method and plate coating method(MIC(MBC)value was reduced by half);analysis of antibacterial kinetic results showed that The antibacterial rate of Bac8 c modified by LA was significantly increased(bactericidal rate reached 99.9% within 15 minutes).The results of bacterial biofilm experiments showed that LA-Bac8 c had a killing effect on the biofilms that had been generated and could inhibit the formation of biofilms.TEM pictures after the action of Bac8 c and bacteria can be observed,LA-Bac8 c caused severe damage to the cell membrane of bacteria,leading to the leakage of intracellular bacteria and death of cells;depolarization experiments and cell outer membrane permeability experiments further illustrate the effect of LA-Bac8 c on The bacterial cell membrane potential has a strong depolarization effect,and has a severe destructive effect on the outer cell membrane.Second part: Recell technology was used to extract rabbit skin cells,and adipose stem cells were set as control group.Short peptide hydrogel Fmoc-FF mixed with skin cell suspension was used to treat wounds;wounds treated with skin cell suspension had wounds close to skin color in 10 days,the wounds were more beautiful,and the collagen fiber content was very rich and dense,showing new epidermis and blood vessels The number is also abundant;wounds treated with Fmoc-FF mixed skin cell suspension can see the new epidermis after 10 days,and a large number of fibroblasts and blood vessels can be observed,with the highest growth factor content.Recell technology combined with short peptide hydrogel in the skin Tissue repair has shown good application prospects.