# UV/Ozone Treatment of Polymer Surfaces to Enhance Cell Adhesion: The Mechanism and Guidelines for Optimization

## TL;DR

This paper explores how UV/ozone treatment affects polymer surfaces to improve cell adhesion, finding that treatment duration impacts protein adsorption and cell attachment.

## Contribution

The study reveals that short UV/ozone treatment enhances cell adhesion via protein retention in hydrophobic areas, beyond just wettability effects.

## Key findings

- Short UV/ozone treatment (1-2 min) improves cell adhesion, while longer treatment (10+ min) reduces it.
- UVO treatment alters surface chemistry and nanoscale structure, affecting protein adsorption and denaturation.
- Fibronectin and vitronectin retained on hydrophobic regions after short treatment act as cell recognition sites.

## Abstract

Despite the widespread
use of UV/ozone (UVO) treatments to improve
cell adhesion and proliferation on polymer substrates, a complete
understanding of the mechanism has not been achieved. This study investigates
the effect of UVO treatment on the physicochemical properties of polymer
surfaces (polystyrene and cyclo-olefin polymer) and protein adsorption,
focusing on its impact on cell adhesion and the underlying mechanisms.
UVO treatment with short time (1 or 2 min) significantly enhances
cell adhesion, whereas treatment longer than 10 min results in poor
adhesion. The treatment introduces oxygen-containing functional groups
and increases wettability; however, the results indicate that wettability
alone is not a determining factor for cell adhesion. Atomic force
microscopy (AFM) imaging revealed nanoscale structural changes on
treated surfaces, while enzyme-linked immunosorbent assay (ELISA)
and quartz crystal microbalance with energy dissipation (QCM-D) analysis
demonstrated that protein adsorption and denaturation are influenced
by treatment duration. Additionally, the study observed the Vroman
effect, showing that protein exchange on UVO-treated surfaces changes
the composition of the protein layer. It was further suggested that
on surfaces with short UVO treatment, fibronectin (FN) and vitronectin
(VN) trapped on remaining hydrophobic areas serve as cell recognition
sites, thus promoting adhesion. Overall, these findings reveal that
UVO treatment duration influences protein adsorption on polymer surfaces
and improves cell attachment, offering valuable insights for designing
better tissue culture surfaces and enhancing material-cell interactions
in biomedical contexts.