Superhydrophobicity Effects on Spheroid Formation, Structure, and Viability on Co-Culture Conditions

<b>Background/Objectives:</b> Three-dimensional (3D) cell culture models more accurately simulate the in vivo tissue environments as compared to conventional two-dimensional (2D) monolayer cultures. Among these, spheroid cultures are particularly valuable for pharmaceutical research, as they allow for the study of tumor growth, drug responses, and cell-cell interactions in a physiologically relevant manner. Superhydrophobic surfaces (SHSs) have shown a promise in enhancing spheroid formation by reducing cell-substrate adhesion and promoting cell-cell aggregation. This study aims to evaluate the effectiveness of two different SHS coatings (SHS1: fluorinated; SHS2: silicone-based) in generating co-culture spheroids composed of non-tumoral fibroblasts (3T3) and tumoral epidermoid carcinoma cells (A431), thereby mimicking aspects of the tumor microenvironment. <b>Methods:</b> Co-cultures of 3T3 and A431 cells were seeded at varying ratios onto SHS1 and SHS2 substrates to assess their ability to support 3D spheroid formation. Spheroids were characterized by measurements of circularity and size distribution, viability through live/dead staining, and surface topography using 3D profilometry. <b>Results:</b> Spheroid formation was significantly influenced by both the surface properties and the fibroblast-to-carcinoma cell ratio. The fluorinated SHS1 surface facilitated superior cell viability and promoted the formation of well-rounded, uniform spheroids. In contrast, the silicone-based SHS2 surface resulted in less defined spheroidal structures and lower overall viability. Profilometry confirmed more consistent and compact 3D architectures on SHS1. <b>Conclusions:</b> This study demonstrates that SHS1, a fluorinated superhydrophobic coating, is more effective than SHS2 in supporting the formation of viable and structurally coherent 3D co-culture spheroids. These findings underscore the potential of SHS1 as a low-cost, tunable platform for developing in vitro cancer models and advancing the study of tumor-stroma interactions.