In-vitro calcium phosphate formation on cellulose -: Based materials

CaO-SiO2 sol-gel coatings were deposited on natural cellulose-based polymers with a 3D porous network structure. Changes in the sample surface after coating and subsequent soaking in simulated body fluid (SBF) were determined by SEM - EDX, FT-IR and X-ray diffraction analysis. Sample - solution interactions were quantified on the basis of gravimetric and solution analysis. Within 3 days a homogeneous calcium phosphate layer was deposited on the sample surface. Furthermore, the porous structure of the samples was maintained. The Ca/P ratio in the deposited layer was 1.63, which is close to that in hydroxyl carbonated apatite (HCA). At the beginning of Ca-P layer precipitation calcium leaches out from the gel resulting in the formation of Si-OH groups in the surface. The Si-OH groups serve as favorable sites for Ca2+ and (PO4)(3-) absorption from SBF resulting in the formation of a Ca-P enriched layer, which grows by consumption of calcium and phosphorus from the surrounding fluid. Sol-gel coatings of porous structures can be used to enhance osteointegration of porous bone replacement materials and scaffolds for bone tissue engineering..