| Dressing is an important material basis for protecting wounds and promoting wound healing.Bacterial infections cause many problems in the wound recovery process,such as prolonged wound recovery and scarring.Chronic wounds bring great inconvenience to patients’ movements,and are accompanied by pain.Rapid wound healing is an urgent problem for chronic wounds.Therefore,the development of dressings that can not only inhibit bacterial infection,but also actively promote healing is of great significance for wound repair.Studies have shown that electrical stimulation has multiple effects such as antibacterial,guiding cell migration and proliferation during wound healing.Metal microbatteries can provide a stable and autonomous source of electrical stimulation energy,and their integration with medical dressings brings new opportunities for wireless applications of electrical stimulation in the field of wound repair.This project intends to deposit Cu/Zn microbattery arrays on the surfaces of polyethylene/cotton/polyethylene dressings and thermoplastic polyurethane/gelatin by template-assisted magnetron sputtering,using the galvanic reaction generated by Cu/Zn contacting wound blood or exudate To prepare lowadhesion electroactive antibacterial dressing(Cu/Zn@PE/Cotton/PE)and continuous electroactive asymmetric wettability nanofiber dressing(Cu/Zn@TPU/Gel).The study found that the outer surface PE layer of Cu/Zn@PE/Cotton/PE has no polar groups and is not easy to adhere,and the inner layer of cotton fibers can absorb excess wound exudate,prevent the wound from being wet,and prevent the growth of bacteria.At the same time,Cu/Zn@PE/Cotton/PE has good air permeability,gas flux of 600-700 mm/s,water absorption rate of over 300%,and moisture retention rate of over 70%.The initial voltage of the Cu/Zn microbattery is 0.7-0.8V,the initial current is 20-30 μA,the current can be maintained for more than 1 h,the voltage can be maintained for more than 48 h,and electrical stimulation can be continued for 48 h.Cu/Zn@PE/Cotton /PE has obvious antibacterial effect on Escherichia coli and Staphylococcus aureus,and SEM shows that it can deform bacteria by destroying the bacterial cell wall to achieve the purpose of killing bacteria.Meanwhile,the antibacterial effect of Cu/Zn@PE/Cotton/PE relies on the microscale electric field of the Cu/Zn galvanic couple.Microscale electric fields can lead to bacterial death by rapidly increasing intracellular ROS levels and disrupting the metabolic activities of bacterial cells.In addition,the leaching solution of Cu/Zn@PE/Cotton/PE showed no obvious toxicity to human fibroblasts and had good biocompatibility.The gas permeability of Cu/Zn@TPU/Gel is about 40 mm/s,WCA=0°on the Gel side,WCA>120° on the TPU side,and the contact angles of Cu@TPU/Gel and Zn@TPU/Gel are both less than 90°,the current stimulation of 0.878 m A is guaranteed for the first half an hour,and then a stable voltage of about 0.54 V is applied around the wound to enhance the endogenous electric field of the skin,and the sterilization efficiency against Escherichia coli can reach 98.90%,and the sterilization efficiency against Escherichia coli It can reach 99.5%,and the antibacterial effect is remarkable.Sputtering Cu/Zn on PE/Cotton/PE and TPU/Gel to construct microbattery composite electroactive dressings provides a simple,convenient,low-cost,and green preparation method,and the electrostimulation effect formed by Cu/Zn composites is also effective The antibacterial effect is beneficial to reduce the use of antibiotics,and has a huge application prospect in the field of wound repair. |
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