Kinetic Study on Collagen Mineralization by Ultraviolet Absorption Spectra
HUANG Zhao-long1，2，ZHANG Wei1，CUI Fu-zhai1*
1. Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China 2. Department of Chemistry, Mengzi Teachers' College, Mengzi 661100, China
Abstract：The mechanism of collagen mineralization was studied by ultraviolet photometry method. The reaction solution was determined using ultraviolet-visible spectrophotometer by the method of repeat scanning wavelength. The recorded curves provided the spectroscopic and kinetics information of the reaction solution. It was found that the wave trough appeared on the step-like kinetic curve of mineralization of collagen. With the increase in initial concentration of calcium phosphate, the wave trough intensity increased and its position moved forward. The curves of scanning wavelength at different time showed different patterns. By analyzing the change in scanning wavelength curves, and the X-ray diffraction spectra of specimens before and after the wave trough position (the specimens were obtained by quickly freezing the solution and freeze-drying)，it was suggested that gelation and phase separation occurred during the process of collagen mineralization. Collagen molecules loading calcium were cross-linked by newly formed DCPD in a “point to point" mode. The phase separation occurred in the fluid-filled space and the wave trough occurred in the ultraviolet absorption spectrum. Based on the mechanism the varieties of phenomena in the ultraviolet absorption spectrum during collagen mineralization were explained.
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