Self assembly of biomimetic hydroxyapatite on the surface of different polymer thin films

Abstract

The role of the process of designing a scaffold in bone tissue engineering is to provide optimal conditions for new bone tissue growth. The primary concern of such engineering is to create an adequate nanotopology of the scaffold inner walls, which can initiate the growth and activity of bone cells. Here, we present a completely new scaffold designing process based on a biomimetic approach in order to improve the nanostructure of pore walls of previously-made calcium hydroxyapatite (CHA) porous scaffolds. CHA porous scaffolds were covered with different polymer thin films (alginate, cellulose and PLGA) and exposed to simulated body fluid (SBF) for 42 days. SBF induced in situ formation of "bone-like" apatite phases on the surface of CHA/polymer composites. Fourier Transformed Infrared (FTIR) spectroscopy showed that the biomimetically-assembled phase is CHA of slightly shifted stoichiometry. X-ray diffraction confirmed that CHA is self-assembled on the surface of all investigated thin films. The calculation of crystallite sizes showed small differences in the degree of crystallinity between different samples. Scanning electron microscopy revealed a dominant blow-ball morphology of CHA particles (size 1 - 5 mu m) with nano-sized branches on their surfaces.