Controlled biodegradation of AZ31 alloy by chitosan/Fe-doped bioactive glass composite coating deposited via electrophoretic deposition for orthopaedic implants.

The fast degradation rate of implants of AZ 31 alloy in the physiological body fluid is a critical problem for orthopaedic applications. The surface modification of AZ 31 can regulate fast degradation by depositing a biocompatible composite coating. Herein, chitosan/ iron-doped bioactive glass (Fe-doped BG) particles were deposited on AZ 31 via electrophoretic deposition (EPD) at optimized parameters (electric field 15 V/cm with 5 min as deposition time). Scanning electron microscopy (SEM) images revealed that the composite coating exhibited uniform morphology with a thickness of 32.5 ± 2.5 μm, while energy dispersive spectroscopy (EDS) and X-ray fluorescence (XRF) confirmed the presence of Fe, Ca, and Si in the composite coating. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of the functional groups of the composite coating. The composite coating exhibited the average roughness (Ra) of 1.32 ± 0.03 μm with a moderate hydrophilic nature (contact angle 68 ± 2.5°) which would be favorable for a cellular response. The composite coating exhibited 3 N adhesion strength evaluated by scratch test. The turbidity test revealed the antibacterial nature of the composite coating. The alkaline phosphate (ALP) activity was also assessed to confirm the bioactive nature of the composite coating. Electrochemical impedance spectroscopy (EIS) showed improved barrier properties by increased charge transfer resistance. The composite coating controlled the degradation rate of AZ 31 (best results compared to the literature) for orthopaedic applications.