Dynamic-Cross-Linked, Regulated, and Controllable Mineralization Degree and Morphology of Collagen Biomineralization

The cross-linking process of collagen is one of the more important ways to improve the mineralization ability of collagen. However, the regulatory effect of dynamic cross-linking on biomineralization in vitro remains unclear. Dynamic-cross-linked mineralized collagen under different cross-linking processes, according to the process of cross-linking and mineralization of natural bone, was prepared in this study. Mineralization was performed for 12 h at 4, 8, and 12 h of collagen cross-linking. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the characteristics of dynamic-cross-linked mineralization in terms of morphological transformation and distribution. Fourier transform infrared spectroscopy (FTIR) analysis showed the crystallinity characteristics of the hydroxyapatite (HA) crystal formation. Pre-cross-linked dynamic-cross-linked mineralization refers to the process of cross-linking for a period of time and then side cross-linked mineralization. The mineral content, enzyme stability, and mechanical properties of mineralized collagen were improved through a dynamic cross-linking process of pre-cross-linking. The swelling performance was reduced through the dynamic cross-linking process of pre-cross-linking. This study suggests that the dynamic cross-linking process through pre-cross-linking could make it easier for minerals to permeate and deposit between collagen fibers, improve mineralization efficiency, and, thus, enhance the mechanical strength of biomineralization. This study can provide new ideas and a theoretical basis for designing mineralized collagen scaffolds with better bone repair ability.