Microscopic visualization of cell - Cold sprayed bio-coating interfaces: An intermediate layer formed during the culturing mediates the behaviors of the cells

摘要

Cold spraying has been proved it is a promising method for biomaterials surface modification and additive manufacturing. Fundamental understanding of the cell-biomaterial interaction is essential for design and fabrication of biomaterials for their biomedical applications. Here we report the evolutional characteristics of the interfaces between osteoblast cells and cold sprayed hydroxyapatite-titanium composite coating. The in situ observation of the interfaces was carried out by focused ion beam-scanning electron microscopy, and influence of the surface characteristics of the coatings on the behaviors of protein adsorption and cell proliferation was examined. Apparent cellular sensing, adhesion, migration, and mineral dissolution after 3 h incubation of the cells were visualized. The predominant existence of fragment particles in the coatings, one of the exceptional features of cold sprayed coating, plays vital role in regulating the cell association and cellular uptake. The presence of Ti and HA fragments at the cell-coating interface had no significant effect on cell viability and cell proliferation. After 5 days culturing, in vitro cell fusion and mineralization with the formation of an intermediate layer were evidenced on the coating, suggesting rapid regeneration and accelerated establishment of boneimplant integration. These critical phenomena occurred at different periods of culturing would facilitate understanding the influence of specific surface features of biomaterials on cell responses, and shed light on the development of manufacturing techniques for biomaterials.