Modification of silk fibroin nanofibers scaffold by PAMAM dendrimer for cell culture

Fibroin is a protein that has been extensively studied for biomedical application. In the present study, silk was dissolved in CaCl2-C2H5OH-H2O in order to obtain silk fibroin (SF) solution, and it was then lyophilized in freeze-dryer. The electrospinning of SF sponge was performed at different fibroin concentrations. SF nanofibers were modified by crosslinking PAMAM dendrimers to carboxylic-terminated fibroin, via EDC and NHS. The modified SF nanofibers scaffold was evaluated by SEM, X-Ray diffraction, FTIR and MTT assay. SEM micrograph showed that the electrospun containing 7% (w/w) fibroin had continuous fibers and an average diameter of 80 nm. Through treatment, conformational transitions of the SF nanofibers from random coil to β-sheet occurred rapidly, confirmed by FTIR and X-Ray diffraction. FTIR spectrum showed amide peaks, which confirmed the existence of fibroin. The modification results of analysis demonstrated that the amino groups were more established on the surface of the SF nanofiber scaffold. Biocompatibility tests were carried out through seeding fibroblasts cell line L929 on nanofibers. Adhesion and proliferation of fibroblasts were investigated by MTT assay, which showed no cytotoxicity. Therefore, fibroin nanofibers scaffolds appear to be a probable choice for potential use in tissue engineering.