Collagen-supported CaCO3 cylindrical particles enhance Ti bioactivity

Abstract Even though Ti displays outstanding properties as a bone-substituting material, its low osseointegration rate has motivated several studies to improve its surface features and thus overcome this limitation. In this sense, physical and chemical modifications by immobilization of bioactive cues are a promising tool to enhance Ti biological responses. Here, we used the layer-by-layer (LbL) technique to modify Ti surface with collagen (Col), the most abundant protein in the bone extracellular matrix, associated with a hierarchical topography through immobilization of CaCO 3 particles with controlled size and morphology. Infrared spectroscopy and scanning electron microscopy revealed that Col and CaCO 3 particles were immobilized on Ti, to form a homogeneous film. Contact angle measurements demonstrated that Ti surface modification increased the total surface free energy and its polar component, to alter Ti wettability. Ti roughness also increased after film formation as evidenced by confocal microscopy images. Exposure to simulated body fluid and osteoblast culture attested that the films were bioactive and suitable for cell proliferation. In summary, the approach described herein modifies Ti surface properties such as roughness, charge, and chemical composition, to enhance the biological response of Ti implants.