@article{Liu2025, 
author = {Xi Liu and Jinglong Pan and You Lv and Xu Wang and Xiaoze Ma and Xinxin Zhang and Guangyi Cai and Zehua Dong},
title = {Near-infrared responsive polycaprolactone coatings for magnesium implants: Photodynamic antibacterial and controllable dissolution},
year = {2025},
journal = {Journal of Magnesium and Alloys},
volume = {13},
number = {4},
pages = {1671-1684},
keywords = {Magnesium, Near infrared irradiation, Photodynamic antibacterial, Photothermal effect, Controlled dissolution},
url = {https://www.sciopen.com/article/10.1016/j.jma.2024.11.013},
doi = {10.1016/j.jma.2024.11.013},
abstract = {Magnesium implants have received widespread attention in orthopaedic surgery. However, the mechanical degradation and concurrent inflammation caused by the rapid corrosion of Mg limits their applications. In this study, a kind of unique core-shell heterojunction CuS@PPy nanostructures was synthesized and then incorporated in polycaprolactone (PCL) to construct an intelligent coating (CuS@PPy/PCL) on micro-arc-oxidized Mg implants. The PCL-based coating can realize near-infrared (NIR)-driven antibacterial and controllable Mg dissolution according to different bone healing stages. At the beginning of bone remodelling, the coating exhibits promising antibacterial properties with 99.67% and 99.17% efficacy against S. aureus and E. coli, respectively, thanks to the singlet oxygen (1O2) and alkoxyl radicals (RO·) generated by the photodynamic effect of CuS@PPy heterojunction under low-power NIR light (1.5 W/cm2). In the bone reparative stage, the PCL-based coating can maintain high corrosion resistance to meet the mechanical requirements of Mg implants in human body fluid. However, after the complete rehabilitation of bones, through a high-power (2 W/cm2) NIR light, the PCL-based coating changed from an elastic to a viscous flow state (44.7 °C) under the photothermal effects of CuS@PPy, leading to quick degradation of the PCL-based coating and following accelerating dissolution of the Mg implant (avoiding secondary surgery). Hopefully, this NIR-responsive coating may provide an innovative method for the antibacterial and controllable dissolution of Mg implants.}
}