In vitro evaluation of degradation, cytocompatibility and antibacterial property of polycaprolactone/hydroxyapatite composite coating on bioresorbable magnesium alloy

Polycaprolactone/hydroxyapatite (PCL/HA) composite coating was fabricated by a combination of hydrothermal and dipping methods to delay the degradation of Mg alloy AZ31 as bioresorbable materials. The PCL/HA coating was composed of nano rod-shape HA crystals and PCL filled in the space of HA crystals. Compared with the single HA coating, the binding strength between the PCL/HA composite coating and Mg alloy was obviously improved and the PCL/HA coating still adhered to the surface of AZ31 substrate even after 38 days of immersion. The electrochemical corrosion rate of HA coated sample was reduced by ten times after being filled by PCL. The electrochemical impedance spectroscopy (EIS) and immersion test results showed that the PCL/HA composite coating could provide a more effective barrier for Mg substrate than the HA coating alone. The cytocompatibility and the antibacterial property of HA coating and PCL/HA coating were evaluated by culturing with bone marrow-derived mesenchymal stem cells (BMSCs) and methicillin-resistant staphylococcus aureus (MRSA) for 24 h under direct culture conditions, respectively. The PCL/HA composite coating showed better BMSC cell compatibility, more suitable for BMSC adhesion than HA coating alone and showed a potential application prospect as a biological materials. However, from the perspective of clinical applications, the antibacterial property of PCL/HA composite coating needs to be further improved.