Stabilizing light-responsive azobenzene films in an aqueous environment with thin polymer coatings

Reproducing cell-cell and cell-extracellular matrix (ECM) interactions remains a challenge when developing new biomaterials. Especially, the dynamic nature of the ECM is often neglected when cells are cultured <i>in vitro</i>. Light-responsive materials are promising candidates to mimic the natural behavior of the ECM. However, their long-term stability under cell culture conditions has not been widely studied. Here, we explore the impact of thin poly(dimethylsiloxane) (PDMS) and poly(<i>para</i>-chloroxylylene) (parylene C) coatings on the stability and biocompatibility of azobenzene-based films that can be photopatterned in response to laser interference irradiation. We study the effect of the polymer coatings on the formation, erasure, and reconfiguration of surface relief gratings (SRGs) in dry and aqueous environments. Our results show that parylene C provides significant advantages over PDMS coatings, including improved stability, biocompatibility, and cell adhesion, opening new possibilities for cell-culture-compatible azobenzene-based materials in biomedical applications.