Physically Cross-Linked Hydrogels Based on Poly(vinyl alcohol) and Gelatin for Independent Modulation of Mechanical Cues in Cell Adhesion Studies

Mechanical properties of biomaterials constitute a key parameter in regulating cellular responses. However, isolating the mechanical influence on cell behavior remains challenging due to the interdependent changes in chemical composition (e.g., polymer chain concentration or type, cross-linking agent, etc.) when modifying a single variable. Herein, noncovalently cross-linked hydrogels comprising poly(vinyl alcohol) (PVA) and gelatin (GEL) with gradient mechanical strength are fabricated by controlling the total freezing-thawing repetitions applied to the PVA-GEL mixture, in which the mechanical properties of hydrogels are successfully decoupled from the chemical composition for cell adhesion studies. The L929 cells prefer the stiff PVA-GEL hydrogel surfaces over the soft ones, uncovering significant variations in cellular attachment and spreading patterns. This strategy may provide a basis for systematically investigating the contribution of specific cues to cellular adhesion processes.