Construction And Preliminary Evaluation Of Collagen-fibroin Scaffolds Loaded With Silver Nanoparticles

ObjectiveTo construct a functional tissue engineering dermal scaffold-collagen/fibroin scaffolds loaded with silver nanoparticles(NAg-CFS),and evaluate its microstructure and biological properties preliminarily in order to explore new application methods ofNAg in tissue engineering skin.MethodsCollagen I was obtained from achilles tendon of bovine by means of pepsin degestion and acid extraction.The silk fibroin was obtained from silkworm cocoons via degumming,salting out and dialysis.Collagen and silk fibroin both at a concentration fo 5 mg/mL were mixed in a volume ratio of 1:1,followed by mixing.the nano-silver solution at a concentration of 10 mg/mL with the collagen-silk fibroin solution in a volume ratio of 1:1000.Collagen-fibroin scaffolds loaded with silver nanoparticles(NAg-CFS)and Collagen-fibroin scaffolds without silver nanoparticles were constructed via freeze-drying.Four dorsal full-thickness skin defect wounds were made on 18 Sprague-Dawley rats.These two kinds of scaffolds were transplanted to the wounds as planned.Six SD rats were sacrificed at day 7th,14th and 28th after operation.Every wound was observed and photographed,followed by harvesting tissue samples.The inflammatory cells of wounds were observed by Hematoxylin/eosin(HE)staining,the macrophages of wounds were reflected through CD68 immunohistochemical staining,and the expressions of IL-6 and IL-10 mRNA of wounds were detected via RT-PCR.Student-t test was used to analyze the data.Results(1)Scanning electron microscope showed that CFS was similar to NAg-CFS in microstructure.(2)As general obervation of wounds showed,scaffolds adhere to wounds more firmly,and the inflammation of wounds was slighter in the experimental group,while the inflammation of wounds was stronger and scaffolds were easy to fall in the control group.(3)HE staining showed that there were fewer inflammatory cells infiltrating scaffolds and wounds in the experimental group compared with the control group at all of the planned time points.(4)Immunohistochemical staining of CD68 showed that macrophage infiltration of wounds and scaffolds in the experimental group was insignificant than that in the control group.(5)RT-PCR results showed that the relative expressions of pro-inflammatory cytokine IL-6 mRNA in the experimental group were lower than those in the control group at all of the planned time points significantly.The relative expression of anti-inflammation cytokine IL-10 mRNA in the experimental group was significantly higher than that in the control group at the 14th day after operation(p<0.05).ConclusionIn this study,a collagen-fiborin dermal scaffold loaded with silver nanoparticles was successfully constructed,and the application of silver nanoparticles in tissue engineered dermal scaffold composed of these two natural materials was explored preliminarily.The results showed that this scaffold could alleviate inflammation response of itself and surrounding wound tissue.