[Effects of microstructure of mineralized collagen scaffolds on cell morphology of MG 63]

To evaluate the effects of the microstructure of mineralized collagen scaffolds on cell morphology of MG 63.

The extrafibrillarly-mineralized collagen (EMC) and intrafibrillarly-mineralized collagen (IMC) scaffolds were fabricated separately by a conventional mineralization approach and a biomimetic, bottom-up mineralization approach. Scanning electron microscopy (SEM) was employed to examine the microstructure of the mineralized collagen scaffolds and cell-scaffold interactions. The effects of the mineralization methods on cell adhesion to the surface of the collagen scaffolds were analyzed by laser scanning microscope (LSM).

The two mineralized collagen scaffolds exhibited different microstructures, including the size, morphology and location of the apatites in collagen nanofibers by SEM imaging. In the EMC scaffold, flower-like aggregates randomly deposited around the collagen nanofibers, while no apatite was observed on the surface of the nanofibers. The presence of an intrafibrillar apatite mineral phase in the IMC scaffold was confirmed using energy dispersive X-ray spectroscopy (EDS) coupled to SEM, with the Ca:P ratio of approximately 1.48.This chemical composition was similar to natural bone tissue. The LSM results showed that the IMC scaffold could promote cell spreading compared with the EMC scaffold. Furthermore, the cells cultured on the IMC scaffold (18.54 ± 2.71) showed higher density of vinculin staining than those on the EMC scaffold (14.29 ± 1.32). From the SEM examination, both mineralized collagen scaffolds showed good biocompatibility. However, the cells exhibited different morphology on different scaffolds.

The microstructure of the mineralized collagen scaffolds can affect the initial cell adhesion and morphology. Furthermore, the IMC scaffold can promote cell adhesion and spreading. The present study will help us to fabricate novel biomimetic materials for alveolar bone regeneration.