Cytocompatibility of Titanium Microsphere-Based Surfaces

The topography at the micro/nanoscale level for biomaterial surfaces has been thought to play vital roles in their interactions with cells. However, discovering the interdisciplinary mechanisms underlying how cells respond to micro-nanostructured topography features still remains a challenge. In this work, ∼37 μm 3D printing used titanium microspheres and their further hierarchical micro-nanostructured spheres through hydrothermal treatment were adopted to construct typical model surface topographies to study the preosteoblastic cell responses (adhesion, proliferation, and differentiation). We here demonstrated that not only the hierarchical micro-nanostructured surface topography but also their distribution density played critical role on cell cytocompatibility. The microstructured topography feature surface with middle-density distributed titanium microspheres showed significantly enhanced cell responses, which might be attributed to the better cellular interaction due to the cell aggregates. However, the hierarchical micro-nanostructured topography surface, regardless of the distribution density of titanium microspheres, improved the cell-surface interactions because of the enhanced initial protein adsorption, thereby reducing the cell aggregates and consequently their responses. This work, therefore, provides new insights into the fundamental understanding of cell-material interactions and will have a profound impact on further designing micro-nanostructured topography surfaces to control cell responses.