Bio-inspired Hydroxyapatite/Gelatin Transparent Nanocomposites

Hydroxyapatite (HA) nanoparticles impart outstanding mechanical properties to organic-inorganic nanocomposites in bone. Inspired by the composite structure of HA nanoparticles and collagen in bone, a high performance HA/gelatin nanocomposite was first developed. The nanocomposites have much better mechanical properties (elongation at break 29.9%, tensile strength 90.7 MPa, Young's modulus 5.24 GPa) than pure gelatin films (elongation at break 9.3%, tensile strength 90.8 MPa, Young's modulus 2.5 GPa). In addition, the composite films keep a high transmittance in visible wavelength range from 0% to 60% of the HA solid content. These differences in properties are attributed to the homogeneous distribution of HA nanoparticles in the gelatin polymer matrix and the strong interaction between the particle surfaces and the gelatin molecules. This protocol should be promising for HA-based nanocomposites with enhanced mechanical properties for biomedical applications.