Modification of electrophoretic deposition of chitosan–bioactive glass–hydroxyapatite nanocomposite coatings for orthopedic applications by changing voltage and deposition time

This article presents electrophoretic depositions of chitosan (CS), bioactive glass (BG), and hydroxyapatite (HA) applied on titanium (Ti) substrate from ethanol-based suspension. The strategy was utilized to modify the deposition of particles with different values of sizes and Zeta potentials, and consequently obtain desirable nanocomposite coating. SEM studies showed that uniform distribution of particles was obtained on isolated substrate at pH 4.5. Moreover, modified deposition of BG microparticles (<37 µm) and HA nanoparticles (<150 nm) in chitosan matrix was reached by changing voltage and deposition time. The results of X-ray diffraction (XRD) revealed a composite with high content of HA was fabricated at pH 4.5, V=20 V, and t=15 min. The deposition mechanism at the initial and final times was significantly related to self-assembly of HA nanoparticles that chelated by cationic macromolecular chains and located on BG microparticles, and CS-coated particulates of HA nanoparticles, respectively. The results of potentiodynamic polarization and electrochemical impedance spectroscopy studies demonstrated that the CS–BG–HA composite coating acts as a barrier layer in corrected simulated body fluid (C-SBF).