Abstract
Immobilization of Epidermal Growth Factor (EGF) has been shown to inhibit endocytosis and regulate cell proliferation and cell differentiation. However, nonspecific immobilization of EGF on substrate has been demonstrated to drastically diminish EGF bioactivity. In this thesis, we would like to study immobilized EGF property and binding ability by protein-protein interaction, cell signaling transduction and tissue formation. Three factors of EGF immobilization will be discussed: (1) Density of immobilization. (2) Linkage of immobilization. (3) EGF-EGFr binding enhancement by Moutan Cortex. The protein-protein interaction result showed that immobilized EGF density with 50-1000 pg/mm2 did not affect its affinity and activity. Immobilized EGF with appropriate orientation on SPR chip can maintain its function and activity for 16 days, inducing EGFr phosphorylation in cell experiment and more new bone tissue formation in bone repair assessment. In the case of binding enhancer treatment, Moutan Cortex enhanced EGF and EGFr 10-fold binding affinity in SPR experiment and better bone repair in animal experiment. These results supported that affinity enhancement can induce more cell signaling transduction for tissue regeneration. Therefore, the regulation of EGF-EGFr interaction is significant for signaling transduction and bone formation.