Ultraviolet Radiant Energy-Dependent Functionalization Regulates Cellular Behavior on Titanium Dioxide Nanodots.

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Cell Biology

Background:

• Titanium dioxide (TiO2) photofunctionalization is a promising surface modification for enhancing implant osseointegration.
• The underlying mechanisms of TiO2 photofunctionalization remain incompletely understood, limiting clinical translation.

Purpose of the Study:

• To investigate the ultraviolet (UV) radiant energy-dependent functionalization mechanism of TiO2 nanodots (TN).
• To elucidate how UV radiant energy accumulation influences cell behavior and osseointegration on TN surfaces.

Main Methods:

• Systematic application of varying UV radiant energy (URE) to TN surfaces.
• Assessment of cell adhesion, proliferation, and osteogenic differentiation on treated TN surfaces.
• Analysis of surface physicochemical changes, including extracellular matrix (ECM) protein adsorption and hydroxyl group reconstruction.
• Investigation of intracellular signaling pathways (FAK-RHOA, ERK1/2) involved in URE-dependent cell responses.

Main Results:

• Cell adhesion, proliferation, and osteogenic differentiation on TN surfaces increased with URE accumulation.
• Optimal functionalization was achieved at 2000 mJ/cm2 URE, significantly enhancing cell-specific behaviors.
• Enhanced cell behaviors were linked to ECM protein adsorption and functional site exposure, driven by URE-induced surface changes.
• A correlation between URE and surface hydroxyl group reconstruction was identified as a key functionalization mechanism.
• Synergistic activation of FAK-RHOA and ERK1/2 signaling pathways mediated the URE-dependent cellular responses.

Conclusions:

• This study reveals a novel UV radiant energy-dependent photofunctionalization mechanism for TiO2 nanodots.
• The findings highlight the role of surface physicochemical alterations and specific signaling pathways in mediating enhanced osseointegration.
• The results provide crucial insights for optimizing implant surface design and photofunctionalization protocols for clinical applications.