Bioactive Nanocomposite Coatings for Visible-Light Illumination Promoted Surface-Mediated Gene Delivery

Gene delivery based on bioactive coatings on collagen has great potentials for bone repair applications. Meanwhile, controlled gene delivery at specific times/regions is essential for an efficient and complete bone reconstruction process. However, spatio-temporal regulation of gene release and delivery remains a great challenge. In this paper, we used visible-light illumination to effectively regulate gene release and subsequent delivery into biological cells. A visible-light responsive and bioactive nanocomposite coating (based on collagen/gold-nanoparticles, e.g., Col/AuNPs) was prepared through hydrothermal and sol-gel processes and used as a loading platform for complexes of enhanced green fluorescent protein and Lipofectamine2000 (LF/GFP). Results showed that the amount of immobilized LF/GFP was increased on Col/AuNPs and the release of pre-adsorbed LF/GFP was significantly enhanced in a spatio-temporal and controllable manner under the visible-light illumination. Moreover, the cellular intake of released gene was improved, thus enhancing gene expression efficiency of the cells. The mechanism of enhanced controlled gene delivery was attributed to the changes of collagen structures and rearrangement of cytoskeletal structures induced by the photothermal effect. The developed Col/AuNPs composite coating is effective for both controlled surface-mediated gene delivery and gene-mediated bone repair.