Simple surface treatment of conjugated polymers for enhanced cell adhesion using UV-Ozone

Aligning the material properties of organic semiconducting polymers to effectively interface with biological matter is critical for their use in bioelectronic devices. Synthetic modification and advanced processing techniques have typically been employed to promote cell adhesion and growth. In this study we apply UV-Ozone (UVO) treatment as a simple and accessible alternative for modifying pDPP3T films. Exposure to UVO increases polarity of the semiconductor surface, as confirmed by contact angle and XPS analysis. Surface treatment at and above the optimized time (t ≥ 30 s) consequently led to enhanced Schwann cell growth, with comparable behaviour to standard tissue culture plastic (TCP). Simultaneously, prolonged exposure begins to cause significant changes to the polymer's optical properties, with gradual photobleaching leading to the reduction in semiconducting behavior above 30 s. Leveraging the optimal biointerfacing properties of the UVO-treated pDPP3T, the validity of the technique in supporting cell viability and proliferation upon a semiconducting polymer was tested using electrical impedance spectroscopy. This work demonstrates the potential to more easily integrate conjugated polymers with biological environments, widening the opportunity to explore the interplay between ion diffusion and semiconductor electroactivity in the presence of biological cells.