Growth and differentiation of neural stem cells on a keratin fiber scaffold carrying nerve growth factor

BACKGROUND: It is essential for nerve tissue engineering is to construct a three-dimensional biomaterial scaffold carrying nerve cells, which has huge potential for repair of injured nervous system. OBJECTIVE: To seek the optimal concentration of hydrochloric acid used to treat keratin fibers based on the physical and chemical properties of keratin fibers, and to explore the effect of keratin fibers carrying nerve growth factor (NGF) on the differentiation of neural stem cells. METHODS: Keratin fibers were treated by hydrochloric acid of various concentrations, and their chemical properties were anlayzed by Fourier transform infrared spectroscopy. Then, we determined the optimal concentration of hydrochloric acid to treat keratin fibers. Subsequently, NGF was loaded onto the keratin fibers as shown by the Fourier transform infrared spectroscopy. Neural stem cells were co-cultured with keratin fibers with or without NGF for 10 days, and the expression of MAP2, MBP, GFAP and the percentage of nerve cells were thereafter detected by immunofluorescence. RESULTS AND CONCLUSION: The highest content of exposed carboxyl on the fiber surface appeared after treatment of keratin fibers with 8 mol/L hydrochloric acid. After 10 days of co-culture, the percentage of nerve cells was significantly higher in the keratin fiber-NGF group than the keratin fiber and control groups. Findings from the present study indicate that co-culture with keratin fibers carrying NGF can dramatically increase the percentage of nerve cells differentiating from neural stem cells.