NGF release from thermo-responsive collagen-polyNIPAam polymer networks supports neuronal cell growth and differentiation

The combination of thermo-sensitive polymer and natural macromolecules such as collagen type I can produce biomimetic scaffolds with enhanced properties for clinical translation. This study describes the preparation of semi-Interpenetrated Networks (semi-IPNs) of crosslinked poly(N-isopropylacrylamide), or PNIPAam, with collagen type I. The collagen-PNIPAam networks with varying collagen content were characterized using Fourier transform infrared spectroscopy techniques and their thermal responsiveness was evaluated by swelling experiments, differential scanning calorimetric (DSC) analysis. Rheological studies were performed at constant frequency and oscillating stress. PNIPAam and semi-IPNs were preloaded with nerve growth factor (NGF), and the NGF releasing profiles at different temperatures were studied using Enzyme-Linked ImmunoSorbent Assay (ELISA). The growth and differentiation of PC12 cells on NGF PNIPAam and collagen-PNIPAam scaffolds were investigated in this study. Neurite length and neurite number of differentiated PC12 cells increased with the increase in collagen content in the scaffolds. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res 94A: 457-465,2010