Electric field-induced deposition of polydopamine and polydopamine-based composite coating for enhanced osteogenesis

Polydopamine (PDA), recognized as a vital bioadhesive, plays a critical role in the development of highly adhesive coatings with tunable biofunctional properties on metallic artificial joint surfaces. Electrophoretic deposition (EPD) has emerged as a facile and efficient technique for coating fabrication. However, the mechanism underlying the formation of PDA coating under electric field, as well as the deposition kinetics of PDA-based composite coating and their influence on biological functionalities, have yet to be thoroughly investigated. In this study, EPD is employed to achieve rapid deposition of uniform PDA-based coatings onto Ti substrate. The electric field-induced polymerization of dopamine is revealed through the examination of chemical composition of solutions around the electrodes and color change of electrolyte during EPD process. The resulting composite coating, consisting of PDA, chitosan, and drug-loaded gelatin nanospheres deposited on Ti substrate, not only endows the material with photothermal-responsive drug release behavior, but also enhanced biocompatibility, bioactivity and accelerated osteogenesis compared to bare Ti. In summary, the rapid EPD technique has yielded PDA-based coating onto Ti substrates that boast excellent bioactivity and osteogenic properties, realizing the functionalization modification of Ti-based implants and rendering them highly promising candidates for orthopedic implant applications.