Mild photothermal effect of titania nanotubes array as a promising solution for peri-implantitis

Abstract

Peri-implantitis is the main cause of implant failure with limited clinical management. Recently, the photothermal therapy (PTT) has attracted more and more attention, due to its convenient and efficient erasure of bacteria. Unfortunately, the high temperature may also cause healthy tissues damage, so that there is a call for the balance between “kill and heal” during PTT. Here, the disregarded photothermal effect of titania nanotubes array (TiNTs) is investigated, to realize the mild PTT (mPTT) idea. It is found that the delivered heat is inversely proportional to TiNTs diameters (30–80 nm) and in proportional to NIR light power (300–2000 mW/cm2). The maximum temperature elevation is reached within 4–6 min (13.4℃ under 300 mW/cm2), which belongs to the temperature range of mPTT. In addition, the peri-implantitis related cells including macrophages, endothelial progenitor cells and osteoblasts all exhibit favorable phenotype alterations after mPTT. Specifically, the macrophages are undergoing M2 polarization (anti-inflammation, pro-healing), endothelial progenitor cells show functional suppression (abnormal vascularization inhibition) and osteoblasts exhibit enhanced osteogenic differentiation (beneficial for new bone repair). In conclusion, these findings suggest that mPTT conveyed by TiNTs may control inflammation and promote bone regeneration, which may be a promising choice for peri-implantitis management.