Preparation Of Xenogenic Acellular Dermal Matrix (XADM) Combined With Nano-silver And Its Antibacterial Effects Evaluation

Objective1. The minimal inhibitory concentration (MIC) and minimumbactericidal concentration (MBC) of nano-silver solution are tested by different methodsrespectively to evaluate the antibacterial effects of nano-silver.2. A convenientpreparation method to combine nano-silver with xenogenic acellular dermal matrix(XADM) which can enhance the antibacterial properties of XADM is introduced and acomposite dressing having both the biological activity of XADM and the excellentantibacterial effect of nano-silver is obtained.3. The antibacterial effects ofNano-silver/XADM, compared with the tradition simple dressing, are assessed in vitro.4. The slow-release property of this composite dressing is evaluated in vitro.5. animalmodel of burns is prepared, and the conditions to get the different depths are explored.6.Th antibacterial effects of the composite dressing are assessed in animal model of burnsin vivo.Methods1. The MIC and MBC to Staphylococcus aureus and Pseudomonasaeruginosa are determined by using standard method respectively.2. The compositedressing is made by soaking XADM in Nano-silver solution.3. Using Kirby-Baucermethod, the antibacterial properties are assessed by comparing Nano-silver/XADMsoaked in different concentrations of nano-silver.4. Using hematoplasma instead ofdiffusate from burned surface, the concentration of Ag in and out of thenano-silver/XADM which are soaked in hematoplasma for a certain time are detected.Then the antibacterial properties of nano-silver/XADM soaked are assessed once more.5. Counterweight preheated in water-bath bin is put on the skin of rat for a certain timeto make rat model of burns. Then using different dressings on rat model of burns, theNano-silver/XADM is assessed by four criterias: bacteria count beaneth crust, healingrate, healing grade, healing time. Results1.The MIC to Staphylococcus aureus and Pseudomonas aeruginosa areboth8mg/L. The MIC and MBC to Staphylococcus aureus and Pseudomonasaeruginosa are64mg/L and32mg/L respectively.The antibacterial effect ofnano-silver/XADM to Pseudomonas aeruginosa may be better than the effect of it toStaphylococcus aureus.2. The XADM soaked in nano-silver solution for48hours canstill be soft, flexible and stretchable. The homogeneous distribution of nano-silver onXADM can be observed by electron microscope.3. The K-B cycle become larger withthe increased concentrations of nano-silver solution. In Pseudomonas aeruginosa group,when the concentration is7.8125mg/L or higher, the K-B cycle of Nano-silver/XADMis larger than that of Aikexin. In Staphylococcus aureus group, when the concentrationis15.625mg/L or higher, the K-B cycle of Nano-silver/XADM is larger than that ofAikexin.4. Ag can be released quickly in Aikexin and Nano-silver/XADM, and therelease speed of Ag in XADM is quicker than Aikexin showing a better slow-releaseproperty in XADM.5. In Staphylococcus aureus group, the antibacterial property ofXADM is not bad than Aikexin when the immersed days≤3, and in Pseudomonasaeruginosa group, the antibacterial property of XADM is not bad than Aikexin whenthe immersed days≤5.6. Using our method, the depth of rat model of burns is Ⅰ°，superficialⅡ°，superficialⅡ°，superficial deep Ⅱ°, deep Ⅱ°and Ⅲ°respectivelywhen the experimental conditions are60℃（5s）、60℃（15s）,70℃（10s）,80℃（15s）,90℃（15s）and100℃（15s）.7. Using different dressings in rat model of burns,the nano-silver/XADM is better than other dressings in four criterias: bacteria countbenath crust, healing rate, healing grade, healing time.Conclusions1. Nano-silve possesses good antibacterial effects.2.Nano-silver/XADM can be made by immersing XADM in nano-silver solution.3. Bothimmediate antibacterial effects and lasting antibacterial effects can be observed inNano-silver/XADM.4. In consideration both the antibacterial effects and the propertyof promating healing, Nano-silver/XADM is expected to be a usful new biologicaldressing in the future.