Micro- and nano-injectable composite biomaterials containing calcium phosphate coated with poly(DL-lactide-co-glycolide).

Calcium phosphate/poly(dl-lactide-co-glycolide) (CP/DLPLG) composite biomaterial, in which each CP particle was coated with DLPLG, was synthesized. Two kinds of composites were prepared: microcomposite, with particles 150-200mum in size, and nanocomposite, with the particles 40+/-5nm in size. Using nanoparticles, a new class of injectible composite biomaterials was produced. Based on scanning electron microscopy, atomic force microscopy, differential thermal analysis, thermogravimetric analysis, differential scanning calorimetry and Fourier transform infrared analyses, the structure and phase organization in both biomaterials was identified and in both studied cases CP particles were coated with DLPLG polymer. An injectable composite biomaterial, the characteristics of which depend on the ratio of the phases, was prepared by mixing physiological solution with the nano-CP/DLPLG composite. Rheological studies indicated a possible agglomeration of particles of the injectable nano-CP/DLPLG composite biomaterial with a CP content of 65%.