Effects of protein incorporation on calcium phosphate coating

The incorporation of proteins into calcium phosphate (Ca-P) coatings is expected to alter their properties. The aim of this work is, therefore, to study the effect of protein concentration on the formation of Ca-P film. A biodegradable blend of corn starch/ethylene vinyl alcohol (SEVA-C) was used as substrate and bioactive glass (45S5 Bioglass (R)) was used as a nucleating agent. Bovine serum albumin (BSA) and alpha-amylase were added, separately. at a concentration of 0.5, 1, and 5 mg/mLto simulated body fluid (SBF) solutions. at the nucleation Stage. 

The incorporation of protein molecules was shown to affect the properties of Ca-P coatings in terms of morphology, composition and crystallinity. Both proteins seem to inhibit in some extent and/or retard the growth of Ca-P nuclei at 0.5 and 5 mg/mL concentrations. FTIR analyses revealed the presence of phosphate and carbonate groups, confirming the formation of a Ca-P layer. The characteristic groups of protein molecules were also detected on the IR spectra, which indicate the efficient incorporation of the proteins into the coatings. When alpha-amylase was added to the SBF solution the production of reducing sugars was detected, proving the retention of enzyme activity. These results suggest the carrier potential of Ca-P coatings for the sustained delivery of other biologically active proteins and consequently with a strong potential for inducing bone tissue regeneration. (C) 2008 Elsevier B.V. All rights reserved.