TiO2 nanotubes-MoS2/PDA-LL-37 exhibits efficient anti-bacterial activity and facilitates new bone formation under near-infrared laser irradiation

Abstract Titanium dioxide (TiO 2 ), as one of the titanium (Ti)-based implants, holds a promise for a variety of anti-bacterial application in medical research. In the current study, a functional molybdenum disulfide (MoS 2 )/polydopamine (PDA)-LL-37 coating on titanium dioxide (TiO 2 ) implant was prepared. Anodic oxidation and hydrothermal treatment was given to prepare TiO 2 nanotubes-MoS 2 /PDA-LL-37 (T-M/P-L). The in vitro osteogenic effect of T-M/P-L was evaluated by measuring mesenchymal stem cell (MSC) adhesion, proliferation, alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization, collagen secretion and osteoblast-specific messenger RNAs (mRNAs) expression. The determination on the anti-bacterial ability of T-M/P-L was followed. Furthermore, the ability of T-M/P-L to promote bone formation in vivo was evaluated. Near-infrared (NIR) laser irradiation exposure enabled the T-M/P-L coating-endowed Ti substrates to hold effective anti-bacterial ability. T-M/P-L promoted the adhesion and proliferation of MSCs. In addition, an increase was witnessed regarding the ALP activity, collagen secretion and ECM mineralization, along with the expression of runt-related transcription factor 2, ALP and osteocalcin in the presence of T-M/P-L. Additionally, T-M/P-L could stimulate endothelial cells to secrete vascular endothelial growth factor (VEGF) and promote capillary-like tubule formation. Upon NIR laser irradiation exposure, T-M/P-L not only exhibited efficient in vivo anti-bacterial activity but also facilitated new bone formation. Collectively, T-M/P-L had enhanced anti-bacterial and osteogenic activity under NIR laser irradiation.