Preparation Of Slightly Acidic Electrolytic Temperature-Sensitive Gel And Evaluation Of Its Antibacterial Activity

Slightly acidic electrolyzed water(SAEW)is a disinfectant solution with the function of killing microorganisms by electrolysis of low concentration electrolyte solution,such as Na Cl solution,dilute hydrochloric acid solution or mixed solution of both,in the electrolytic cell.Because of its simple preparation,safety and environmental protection and low cost,it is widely used in medical and health,food safety,pet disinfection and other fields.However,slightly acidic electrolytic water has some limitations because of its heavy dependence on equipment and serious chlorine loss.In order to improve the stability of slightly acidic electrolyzed water,the slightly acidic electrolytic water temperature-sensitive gel was prepared by using chitosan and β-glycerol phosphate disodium hydrate as gel materials.And the in vitro quality evaluation,antibacterial effect and skin wound healing effect of the gel were investigated in order to lay a foundation for the clinical application of slightly acidic electrolytic water thermosensitive gel.The main research contents are as follows:(1)Optimization of preparation process and evaluation of antibacterial activity in vitro of slightly acidic electrolytic waterTaking p H value,Oxidation-Reduction Potential(ORP)and Available Chlorine Concentration(ACC)as indexes,the effects of hydrochloric acid concentration,electrolytic voltage and acid feeding rate on the quality of slightly acidic electrolytic water were investigated,the preparation process of slightly acidic electrolytic water was optimized,and antibacterial activity in vitro of the prepared slightly acidic electrolytic water was evaluated.The results show that: Slightly acidic electrolytic water is of better quality when the concentration of hydrochloric acid is 5%,the water flow rate is 80 L/h,the electrolytic voltage is adjusted to 5 V,the acid feeding rate is 30 s/time,and electrolyzing for 30 min.The p H value is 6.42-6.48,the ORP value is 910-920 mv,and the ACC value is 50.30-52.14 μg/m L.The survival rates of S.aureus and E.coli treated by the slightly acidic electrolytic water after 1min are only 6.61% and 5.32%,showing good antibacterial activity of the slightly acidic electrolytic water.(2)Preparation of slightly acidic electrolytic water temperature-sensitive gel and its effect on antibacterial activity in vitroThe effects of the concentration of chitosan,the concentration of disodium β-glycerophosphate hydrate and the volume ratio of chitosan to disodium β-glycerophosphate hydrate on the gelation time of slightly acidic electrolytic water temperature-sensitive gel were screened by orthogonal design method.The in vitro antibacterial activity of slightly acidic electrolytic water temperature-sensitive gel was evaluated.The results show that: Using slightly acidic electrolytic water as the solvent of β-disodium glycerophosphate hydrate,the mixed solution of 3% chitosan with volume ratio of 1:1 and 60% mass fraction of β-disodium glycerophosphate hydrate was fully stirred and mixed under the condition of ice bath,and the slightly acidic electrolytic water temperature-sensitive gel was obtained by incubating 1min at37°C.The appearance of the gel is opaque and gel-like and has good solubility and long-term water retention.The survival rates of S.aureus and E.coli treated with slightly acidic electrolytic water temperature-sensitive gel were only 2.38% and 0.86%,showing superior antibacterial activity compared with slightly acidic electrolytic water.(3)Effect of hydrogel on the stability of main quality indexes of slightly acidic electrolytic waterThe prepared slightly acidic electrolytic water was stored for 30 days under the conditions of open light,open light,seal light and seal light,respectively,and the changes of p H value,ORP value and ACC value were investigated.The results show that: Slightly acidic electrolytic water is the most stable under dark and closed storage conditions,and the p H value and ORP value do not change significantly after 30 days of storage,but the ACC value only decreases by28.75%.The stability is poor under light and open storage conditions,and the p H value,ORP value and ACC value decrease significantly after 30 days of storage.In order to explore the stability of slightly acidic electrolytic water temperature-sensitive gel,the in vitro antibacterial activity of slightly acidic electrolytic water temperature-sensitive gel and chitosan hydrogel without slightly acidic electrolytic water stored at 4°C for 90 days was investigated.The results show that: Slightly acidic electrolytic water thermosensitive gel always showed better antibacterial activity than chitosan hydrogel stored at 4°C for 90 days,and there was no obvious change in its own antibacterial activity.it shows that the slightly acidic electrolytic water thermosensitive gel can prolong the service life of slightly acidic electrolytic water and improve the stability of slightly acidic electrolytic water.(4)Evaluation of the effect of slightly acidic electrolytic water temperature-sensitive gel on skin wound healingIn order to study the healing effect of slightly acidic electrolytic water thermosensitive gel on skin wound,a rat skin wound model was established,the repair of rat skin wound was observed,and the bacterial load of rat skin wound was detected.The contents of interleukin-6(IL-6),interleukin-1 β(IL-1β),tumor necrosis factor-α(TNF-α),hydroxyproline(HYP)and myeloperoxidase(MPO)in rat skin wound tissue were investigated.The results show that:Slightly acidic electrolytic water thermosensitive gel had no obvious skin irritation to rats,and only 95.41% of the skin wounds of rats healed completely after 12 days of treatment.Slightly acidic electrolytic water temperature-sensitive gel can inhibit the expression of inflammatory factors IL-6,IL-1 β and TNF-α in rat skin wound tissue,reduce the content of MPO,increase the content of HYP and then clear the inflammatory reaction of rat skin wound tissue,reduce the infiltration of inflammatory cells in wound tissue,promote the formation of granulation tissue,increase the thickness of epidermis,accelerate collagen tissue metabolism and fibrosis,and promote the healing of rat skin wound.The experimental results show that slightly acidic electrolytic water temperature-sensitive gel can improve the stability of slightly acidic electrolytic water,prolong the service life,enhance the antibacterial activity,and promote the wound healing of rat skin,which can be further used in clinical research.This study laid a theoretical foundation for the popularization and application of micro-acid electrolytic water temperature-sensitive gel.