Superhydrophobic Cell‐Repellent Microstructures: Plastron‐Mediated Inhibition of A549 Epithelial Cell Adhesion

Abstract Control of cell adhesion is essential for biomedical devices, biosensors, and anti‐fouling coatings. Here, adhesion of A549 epithelial cells is systematically evaluated on silicon substrates with tunable wettability (superhydrophilic to superhydrophobic) and topography (smooth, nanostructured, and micropillared). Superhydrophobic surfaces stabilize a trapped air plastron that minimizes solid–liquid contact, enabling plastron‐mediated physical repellency of cells . The most cell‐repellent surface, composed of 5 µm micropillars with a 7.4% solid–liquid contact fraction, reduced cell density by ≈83% versus a smooth hydrophobic control and ≈95% versus a hydrophilic control at 4 h, and by ≈90% and ≈93%, respectively, after 24 h of incubation, corresponding to an approximate tenfold decrease in cell adhesion. Micropillar arrays outperform nanostructures in resisting cell attachment, owing to large air‐filled gaps exceeding 10 µm that physically prevent cell adhesion. A trade‐off is observed: lower solid‐fraction micropillars provide greater short‐term repellency but lose the plastron over time, enabling delayed fouling, whereas higher‐fraction structures preserve the air layer beyond 72 h but are initially less cell‐repellent due to higher effective cell contact area and smaller air gaps. These results establish that optimized microscale superhydrophobic textures achieve superior and time‐dependent bio‐repellency and introduce a rational design strategy for non‐fouling materials.