Decoding Cytoskeletal Mechanobiology with Tunable Microenvironments.

Mechanical cues from the cellular microenvironment are key regulators of cytoskeletal organization, force generation, and mechanotransduction, yet defining how specific mechanical inputs control distinct cytoskeletal processes remains an ongoing challenge. Mechanically tunable microenvironments have become essential tools for addressing this problem by enabling systematic variation of substrate stiffness, viscoelasticity, and interfacial mechanics under well-controlled conditions. In this review, we survey major classes of tunable platforms used to study cytoskeletal dynamics, including biologically derived matrices, synthetic hydrogels, micropatterned and nanotopographic substrates, and polymeric thin films, highlighting how each approach affords unique insight into cytoskeletal regulation. Beyond material composition, these platforms reveal key mechanistic principles: they allow separation of protrusion, contractility, and adhesion processes; uncover how mechanical coupling drives alignment and polarity; and identify stiffness thresholds that govern force transmission. Control over interface mechanics also enables selective engagement of cytoskeletal modules that are otherwise inseparable on rigid substrates. We conclude by discussing current limitations and emerging opportunities for integrating tunable microenvironments with quantitative measurements of force generation and cytoskeletal organization, advancing a more predictive understanding of how cells sense, transmit, and respond to mechanical information.