A biology research of collagen/silica composite nerve scaffolds in vitro

Abstract

Objective To discuss the effect of collagen/silicon composite scaffolds in the peripheral nerve regeneration, and evaluate the adhesion and proliferation of Schwann cells within the scaffolds. Methods In this study, from March, 2013 to May, 2014, the collagen/silicon composite scaffolds with 5, 10, 25, 50 and 100 μg/ml were made by freeze-drying technology, and the single collagen scaffold without silica nanoparticles was made with the same method as a control group. The diameter and size of the silica nanoparticles were measured by light scattering, and the morphology of silica nanoparticles were scanned by electron microscope. The cellular compatibility of composite scaffolds was inspected by cultivating Schwann cells on the scaffolds in vitro. The morphology of the Schwann cells in different sample were observed under optical microscope. The adhesion and proliferation effect of the Schwann cells on the scaffolds were determined by MTT. The DNA content of the cells were measured by fluorescence spectrophotometer. Experimental data were expressed by mean ± standard deviation (SD) values. Data were analyzed using One-way ANOVA followed by Bonferroni’s post hoc comparison tests. Statistics with a value of P < 0.05 indicated statistical significance. Results The average diameter of the nanoparticles mainly distributed from 150 to 190 nm and showed a spheric morphology. Morphologically, all the cultured cells were observed to be in healthy state in most scaffolds except for the scaffolds with 100 μg/ml silica nanoparticles. Whereas all the cells on other samples displayed spindle shape with axons spreading, and there was no obvious morphology difference for the cells on these samples. The results of cytocompatibility of the collagen/silica composite scaffolds using MTT assay showed that both the viability and proliferation of Schwann cells increased firstly and then decreased with the increasing concentration of silica nanoparticles. And the cells showed much better viability and proliferation when the concentration of silica nonoparticles was 25 μg/ml compared with other samples. While the cell viability was significantly decreased when the concentration of silica nonoparticles was larger than 50 μg/ml, which was consistent with the morphology results. The DNA contents of Schwann cells in scaffolds also increased firstly and then decreased with the increment of silica nanoparticles concentratin, and the cells in the composite scaffolds with 25 μg/ml silica nanoparticles showed the largest DNA contents. Conclusion The collagen/silica composite scaffold with 25 μg/ml may contribute to the regeneration of peripheral nerve in the future. Key words: Silica nanoparticles; Collagen; Nerve scaffold; Schwann cell