In vitro short-time stability of a bioactive glass-chitosan composite coating evaluated by using electrochemical methods

A composite coating consisting from a chitosan (Chit) thin film containing a new bioactive glass SiO2-CaO-P2O5 (BG) was investigated by cyclic voltammetry. The bioactive glass–biopolymer coating has certain porosity and is a good insulator comparing with the biopolymer film. The in vitro short-time stability of Chit and BG-Chit coatings on glassy carbon (GC) electrode is studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), during about 1 day of contact with a protein-free and acellular simulated body fluid (SBF) having an ion concentration nearly equal to that of human blood plasma. The EIS data indicated that after 5 hours of immersion in SBF the Chit dissolution and the adsorption of SBF ions on BG matrix were initiated causing the formation of a new outer biomimetic and biologically active hydroxyapatite protective layer. The CV and EIS measurements results recommend the use of composite BG–Chit coatings for in vivo devices (implants, prostheses and tissue engineering scaffolds).