Preparation And Applied Research In Anti-Infective,Analgesic,and Hemostatic Properties Of Novel Magnesium Boride Hydrogel

Background and objectivesRecently,there has been a significant change in the characteristics of war wounds,manifested as acute wounds of skin and soft tissues being one of the eight new wound classifications.Timely and effective treatment of acute wounds can enable some lightly wounded to return to the battlefield and replenish combat power.Another type of wound is a chronic wound,which is complicated in its pathogenesis,challenging to treat,long in duration,and costly.Thus,wound repair and healing is not only a medical issue but also a military and social issue that deserves attention.Due to their high-water content and permeability,hydrogels can provide a moist wound healing environment for wound healing,making them an excellent dressing agent in clinical application.The development of hydrogels requires the selection of"skeleton materials"and"functional materials."Our previous studies used a modified high-temperature self-propagating combustion method to prepare Nano-mb with good antibacterial and electronic transfer capabilities.However,there are apparent bottlenecks in the transformation research:solid powders are not easy to create a wet healing environment;the hydrolysis rate of magnesium boride nanoparticles is not controllable;and the biological safety of Nano-mb is not controllable.Therefore,our research purpose is to screen suitable hydrogel"skeleton materials,"prepare Nano-mb into hydrogel formulations,and study the biological properties of the new magnesium boride hydrogel in infected,painful,or bleeding wounds.Contents and MethodsUsing the"one-pot reaction,"a novel magnesium boride hydrogel（Sa-mb）was prepared with sodium alginate as the base skeleton and magnesium boride as the crosslinker,and the hydrogel was characterized and analyzed.The biological safety of Sa-mb was evaluated by co-incubating Sa-mb with Ha Ca T cells and then using the CCK-8 detection kit to detect cell viability;by performing a hemolytic test to see the effect of Sa-mb on red blood cells;and by observing the tissue compatibility of Sa-mb through muscle embedding experiments.The anti-infection,analgesic,and hemostatic properties of Sa-mb were studied:bacterial CFU was calculated by co-incubating Sa-mb with bacteria in vitro and using the bacterial viable cell counting method to evaluate the antibacterial ability of Sa-mb;different concentrations of Sa-mb and Nano-mb solutions were co-incubated with PA14,and bacterial CFU were continuously monitored to observe the sustained release behavior of Sa-mb;the mouse wound infection model was established to observe the effect of Sa-mb on wound healing by animal experiments;a mouse shallowⅡdegree burn model was used to mark the analgesic effect of Sa-mb on acute pain wounds;the Hagelhufs test was used to observe the effect of Sa-mb on the latent period of mice thermal stimulation response,and thus infer the performance of Sa-mb in peripheral nerve blockade;and a mouse liver bleeding model was used to evaluate the hemostatic ability of Sa-mb on bleeding wounds.ResultsWe successfully prepared Sa-mb.The XRD qualitative analysis showed that Sa-mb was in accordance with the standard pdf card of magnesium boride（JCPDS:38-1369）,indicating the successful preparation of the hydrogel.The SEM showed that Sa-mb had a three-dimensional network structure of hydrogel.According to the CCK-8 results,after incubation for 12 h,the cell viability of the Sa-mb 500 group decreased significantly compared with the Control group,and the solution group’s cell viability decreased when the magnesium boride reached 400μg/m L.The hemolysis test results showed that when the concentration of magnesium boride was≤500μg/m L,the hemolysis rate of the solution group was higher than 90%,while that of the hydrogel group was<10%,which was statistically significant compared with the control group.The results of the muscle embedding experiment showed that Sa-mb did not lead to necrosis of the surrounding muscle tissue,and no axonal degeneration or demyelination was observed in the nerve at the embedding site.In vitro antimicrobial experiment results showed that the effective concentrations of Sa-mb against PA14,CMCC（B）,and ST398 were 150μg/m L,300μg/m L,and 350μg/m L,respectively,which were statistically significant compared with the control group.The antibacterial ability of Sa-mb gradually increased in the 6-12 h period,and the bacterial survival rate of the Sa-mb 300 group decreased to less than 10%at 12 h.The antibacterial effect lasted until 36 h.Nano-mb solution also showed good antibacterial ability in the 6-12h period.When the concentration of magnesium boride reached 300μg/m L,the bacterial survival rate decreased to less than 10%,and the antibacterial effect lasted until 18 h.The animal experiment results showed that an 80%healing rate was achieved in the mice infected with PA14 after treatment with Sa-mb added with magnesium boride.In comparison,the healing rate of the control group was less than 50%,and the Sa-mb 200 group and Sa-mb500 group were statistically significant compared with the control group.New epidermal layer formation and a noticeable increase of hair follicles were observed in the wounds treated with Sa-mb,Nano-mb solution,and a positive control group.At the same time,epidermalization was not completed in the control group.The results of treatment of acute pain wounds showed that the number of body twists of the Sa-mb 200 treated mice with shallowⅡdegree burn pain wounds was significantly reduced,and the number of body twists of the Sa-mb 500 group was further reduced,which was statistically significant compared with the control group.The results of Hargreave’s test showed that after the treatment of Sa-mb added with magnesium boride on the sciatic nerve of mice,the thermal withdrawal latency was significantly prolonged at the 2 h time point.The effect of prolonging thermal withdrawal latency was still observed at the 6 h time point,which was statistically significant compared with the control group.In addition,the influence of heat withdrawal latency of the positive control group of nerve infiltration anesthesia with lidocaine hydrogel decreased at the 6 h testing time point.The results of the mouse liver bleeding model showed that the average bleeding volume of the Sa-mb group added with magnesium boride was significantly less than that of the blank control group（Sa-mb200 vs.Blank:0.046±0.017 vs.0.140±0.026,p=0.01;Sa-mb500 vs.Blank:0.041±0.012 vs.0.140±0.026,p=0.003）,and the average hemostasis time was also shorter than that of the blank control group（Sa-mb200 vs.Blank:29.571±6.051 vs.154.200±64.612,p=0.003;Sa-mb500 vs.Blank:26.429±6.852 vs.154.200±64.612,p=0.001）.ConclusionsIn Sa-mb,the carboxyl groups of Mg²⁺and alginate produce strong coordination complexes,promoting hydrogel network formation.The boron-hydroxyl groups react with the alginate hydroxyl groups to form stable borate ester bonds,strengthening the hydrogel network structure.In addition,magnesium boride hydrolysis generates an alkaline microenvironment,transforming boron from sp² to sp³,stabilizing the borate ester bonds,and endowing the hydrogel with the responsive p H degradation characteristics,which gives it a well-sustained release capability.When the hydrogel encounters an acidic wound environment,the framework network loosens and releases the magnesium boride entrapped in the hydrogel,which plays its biological property.The results show that Sa-mb has good biocompatibility,and Sa-mb100 also promotes the proliferation of Hacat cells.Sa-mb has shown good anti-infective ability in vitro and in vivo experiments and has an antibacterial effect on gram-positive and gram-negative bacteria,because the anti-infective mechanism of Sa-mb is different from that of conventional antibiotics,it is not easy to cause bacterial resistance.In vivo animal experiments showed that Sa-mb could prevent the wound from contacting the external environment and provide a moist microenvironment for wound repair,promoting wound healing.Sa-mb also has an analgesic effect on acute wounds and can affect the conduction of nerve impulses on the sciatic nerve.Sa-mb also showed the excellent hemostatic effect on bleeding wounds.