Bioinspired synthesis of self-assembled calcium phosphate nanocomposites using block copolymer-peptide conjugates

Thermoreversibly gelling block copolymers conjugated to hydroxyapatite-nucleating peptides were used to template the growth of inorganic calcium phosphate in aqueous solutions. Nuclear magnetic resonance (NMR). Fourier transform infrared (FTIR), transmission electron microscopy, x-ray diffraction, and small-angle scattering were Used to characterize these samples and confirm that the peptides promoted the growth of hydroxyapatite as the inorganic phase. Three different polymer templates were Used with varying charges oil the polymer chains (nonionic. anionic. and zwitterionic), to investigate the role of charge oil mineralization. All of the polymer-inorganic solutions exhibited thermoreversible gelation above room temperature. Nanocomposite formation was confirmed by solid-state NMR, and Several methods identified the Inorganic component as hydroxyapatite. Small angle x-ray scattering and electron microscopy showed thin, elongated crystallites. Thermogravimetric analysis Showed an inorganic content of 30-45 wt% (based oil the mass of the dried,gel at similar to 200 degrees C) in the various samples. Our work offers routes For bioinspired bottom-up approaches for the development of novel, self-assembling, injectable nanocomposite biomaterials for potential orthopedic applications