Polycaprolactone-MXene coating for controlling initial biodegradation of magnesium implant via near-infrared light

The mechanical strength of magnesium implants undergoes a rapid decline after implantation due to bioabsorption, which can lead to the risk of rupture. To ensure sustained mechanical strength and initiate bioabsorption selectively upon specific external stimuli until the bone regains sufficient support, we developed a biosafe near-infrared light (NIR)-sensitive polymer coating using polycaprolactone (PCL) and Ti₃C₂ (MXenes). The synthetic MXene powders were characterized using SEM, EDS, and XRD, and the amount of MXenes had a proliferation-promoting effect on MC3T3-E1, as observed through cell assays. The PCL-MXene coating was successfully prepared on the magnesium surface using the casting coating method, and it can protect the magnesium surface for up to 28 days by decreasing the corrosion ratio. However, the coating can be easily degraded after exposure to NIR light for 20 minutes to expose the magnesium substrate, especially in a liquid environment. Meanwhile, the magnesium implant with the PCL-MXene coating has no cytotoxicity toward MC3T3-E1. These findings can provide a new solution for the development of controlled degradation implants.