Standardizing mechanical dose delivery to cells via nanogroove-guided alignment

The development of novel mechanomedicine technologies critically depends on the ability to administer a well-defined mechanical dosage to cells. Unlike chemical cues, mechanical signals are vectorial rather than scalar, making their precise delivery inherently complex. When external mechanical stimuli are applied to cells seeded on a flat substrate, the mechanical dose experienced by each cell varies depending on its orientation and conformation, rendering consistent and effective mechano-modulation impractical. Here, we introduce a substrate-guided mechanical stimulation strategy that standardizes mechanical dose delivery at the population level by controlling cell orientation. Using nanogrooved PDMS substrates integrated into a uniaxial stretching platform, we induced coherent alignment of NIH3T3 fibroblasts and their mechanosensitive subcellular structures along the direction of applied strains. Cells cultured on flat or nanogrooved substrates were subjected to sustained uniaxial strains of 8% and 29%, and their responses were quantified in real time by live-cell fluorescence imaging. Nanogroove-induced alignment enabled uniform transmission of substrate strain to focal adhesions and the cytoskeleton, resulting in coherent and quantifiable nuclear deformation across the cell population. In contrast, cells on flat substrates exhibited orientation-dependent deformation modes that canceled out at the population level, leading to heterogeneous and attenuated responses. While cellular adaptation to sustained strain was primarily governed by strain magnitude, substrate-guided alignment markedly reduced cell-to-cell variability in mechanical signal perception. Overall, this work establishes cell alignment as a key parameter for standardizing mechanical dose delivery and improving the reproducibility of mechanobiology experiments and the design of mechanically active biomaterials.