Engineering cell culture platforms for outside-in and inside-out mechanobiology across throughput scales

This is the authors' abstract. We don't add key points for this paper.

Mechanical cues are regulators of cellular behavior in health and disease, not merely passive consequences of biochemical programs. As mechanobiology advances, cell-culture systems have shifted from simple assays to scalable platforms probing diverse mechanical environments. This review examines how physical cues affect two levels of regulation: outside-in responses, in which cells react to engineered stiffness and topography, and inside-out-state variables, such as cell-cycle phase and cytoskeletal organization, which set how those cues are converted into phenotypes. We classify platforms by (i) mechanical cue or measurement modality and (ii) experimental throughput, assessed by the number of independently addressed conditions and their acquisition mode, from low-throughput devices to high-throughput plates. Platform design variables, including ligand chemistry, substrate thickness, viscoelasticity, stress relaxation, and geometry, influence mechanobiological outcomes, explaining deviations from simple stiffness response models. In low-throughput studies, researchers establish causal links between matrix elasticity, adhesion maturation, and cell-cycle control. At the same time, higher-throughput arrays reveal that viscoelasticity, ligand context, and lineage identity act as decisive modifiers. For topography, geometric boundary conditions such as adhesive area, anisotropy, and confinement gate proliferative commitment and migration through cytoskeletal and nuclear intermediates. For mechanical probing tools, compartment-specific readouts (cytoplasmic rheology, cortical stiffness, and traction) can report divergent trends across the same cell-cycle transition, underscoring that a single metric is unlikely to capture all relevant aspects of cell mechanical state. Finally, we recommend priorities for standardization, including shared validation metrics, metadata, and integrated mechanical-biological readouts. These efforts, combined with scalable microenvironment platforms, may enable detailed mapping of cell states across mechanical contexts.