Antibacterial Dressing Of PNIPAAm@GO Hydrogel

In recent years,with the continuous improvement of people’s health awareness,the development of antibacterial dressings that can promote wound healing,protect the wound surface,avoid infection,absorb wound exudate,antibacterial and biocompatibility has attracted more and more attention.Medical dressing is a material that provides special functions for wound healing according to the actual situation of the wound.It has unique advantages in absorbing water and moisturizing,avoiding wound adhesion,and reducing secondary damage caused by changing dressings.Because it can replace damaged skin and act as a temporary barrier,avoid wound infection and provide an environment conducive to wound healing.Research on medical dressings involves multidisciplinary research,including biology,mechanics,medicine,physiology,and high molecular materials and other fields.With the continuous deepening of research on medical dressings,people realize that it should not only cover the wound surface,but also have biomedical properties such as good wettability,avoiding wound infection and complications,and promoting wound healing.Although a variety of biological dressings have been developed,bacterial infection of wounds is still to be avoided clinically.Therefore,it is still necessary to develop a more effective medical dressing that is resistant to wound infection,has good biocompatibility,and can promote wound healing.Graphene oxide(GO),as a material with excellent biocompatibility,can promote cell growth through functional modification,so graphene oxide biofunctional materials prepared from it can be used in tissue engineering,areas such as wound treatment and drug release.Combining nanomaterials with specific biological functions and hydrogel medical dressings,the obtained composite materials not only have the softness and good mechanical strength of hydrogels,but also have biomedical functions such as water absorption,moisturizing,and sustained release.The preparation of hydrogel nanocomposites with temperature sensitivity and controllable drug release properties can improve the utilization efficiency of drugs,which has research value and practical significance.In this paper,N-isopropylacrylamide(NIPAAm)was blended with GO under the action of N,N′-methylenebisacrylamide(BIS),using a The PNIPAAm@GO thermosensitive hydrogel that was prepared by the pot method.The interaction between GO and NIPAAm at different temperatures was studied,and the response mechanism was studied.Then,the transition temperature of the thermosensitive hydrogel was adjusted to be close to the human body temperature by optimizing the experimental parameters.Drugs were loaded on the hydrogel to explore its application potential as a wound dressing in antibacterial and wound healing.The main findings of this paper are as follows:(1)N-isopropylacrylamide,graphene oxide,and N,N′-methylenebisacrylamide were prepared by one-pot method to obtain graphene oxide thermosensitive hydrogel PNIPAAm@GO with thermosensitive properties.It was found that PNIPAAm@GO gels have a similar temperature response behavior as PNIPAAm.Compared with the room temperature of 25°C,the size of the hydrogel shrank by 36% at 37°C.The analysis suggests that it is because of the hydrogen bonding and phase transition of the PNIPAAm@GO hydrogel at different temperatures.The resulting internal structure changes results,resulting in a smaller pore size of the internal network structure of the hydrogel as the temperature increases.(2)By adjusting the phase transition temperature of thermosensitive hydrogels,it is found that the phase transition temperature can be controlled by changing the amount of the crosslinking agent N,N′-methylenebisacrylamide in the hydrogel system.The PNIPAAm@GO hydrogel has potential as a wound dressing by regulating its phase transition temperature to body temperature.By studying the relationship between the amount of crosslinking agent BIS and hydrogel swelling,deswelling,temperature responsiveness,temperature impulse responsiveness and mechanical properties,the experimental conditions were optimized: GO:PNIPAAm=1:1.5(w/w),when the crosslinker BIS=5.0 mol%(relative to the amount of NIPAAm),the catalyst APS=263 μL,and the accelerator TEMED=26.3 μL,the phase transition temperature of the hydrogel is 34.8 °C,the swelling rate is 980%,and the water loss is 980%.The compressive modulus is 0.08 MPa.Moreover,when the ambient temperature increased from 25°C to 45°C,the hydrogel exhibited good temperature responsiveness and impulse response characteristics.(3)Ciprofloxacin(Cip)drug loading on PNIPAAm@GO hydrogel by dry dip method to observe the drug release at different temperatures.The results showed that PNIPAAm@GO hydrogel could store the drug at 25°C.The drug can be released at 37°C,and the difference between the two cumulative drug release rates is over 84%.The drug-loaded PNIPAAm@GO hydrogel was tested in terms of cytotoxicity,antibacterial effect,and wound healing.It was found that it has good biocompatibility.In vitro experiments,the results showed that the wound healing rate of the untreated group reached 83% after 14 days,and the wound healing rate of the drug-loaded PNIPAAm@GO hydrogel dressing reached 91%.