Table 1.

Common in vitro mechanical force stimulation methods and their major studied outcomes

Mechanical force	Description	Major outcomes	Benefits	Drawbacks
	Stiffening or softening of extracellular matrix to induce mechanical responses similar to that of native tissue [124,134,240,241]	• Focal adhesion activation • Actin cytoskeleton polymerization • Nuclear stiffening • Cell differentiation • Chromatin organization	• Replicates to native tissue mechanics • No additional apparatus required to induce mechanical signals • No additional apparatus required to induce mechanical signals	• Can have uneven stiffness profiles across surfaces • Harder to image live or fixed cells
	Restricting cell shape through physical impediments or shape of adherent surface [32–35,242]	• Cytoskeleton & nucleus shape • Cell differentiation • Chromatin organization	• Easy to manufacture and implement • Isolates function of cell shape in cellular functions • Can image live or fixed cells	• Low cell density • Partial homology to tissue environment
	Mimicry of fluid shear stress forces found in vasculature systems [31,112–115,243,244]	• Cell and nucleus orientation • Cytoskeleton remodeling	• High homology to vasculature forces • Easy to mimic human pathologies	• Requires use of specially designed bioreactors • Fluid force can be non- uniform between experiment sets
Strain	Stretching of adherent substrate to produce dynamic or static strain forces [6,7,13–17,37,52,56,100,127]	• Actin cytoskeleton • Cell differentiation • Cell proliferation • Focal adhesion signaling • Nuclear signaling and structure • Chromatin organization	• Easy to use • Induces strong regulation of differentiation and stimulation of the actin cytoskeleton	• Requires expensive strain application machinery • Limited by size of specialized cell culture plates
	Low magnitude strain induced by low amplitude, high-frequency vibration [19,37,53,55,56,100]	• Focal adhesions signaling • Cell differentiation • Cell proliferation • Nuclear signaling and structure	• Similar homology to muscle-induced vibration forces observed in native tissue • Can be utilized in cell culture, tissues, and mammalian models	• Requires custom-made bioreactors • Requires long-term exposure to mechanical signals • Less potent mechanical signal compared to strain and fluid shear
	Probing of individual cells and nuclei with rounded-tip atomic force microscopy [100,145,147,169,245]	• Measure Cell and nuclear stiffness • Force induced translocation of mechanically sensitive biomolecules	• Provides high resolution stiffness measurement of cells and nuclei • Targeted mechanical activation of mechanosensitive signaling pathways	• Require expensive equipment Challenging to provide provide population-based measurements • Hard to determine if measuring proper target versus non-desired targets
	Use of magnetic beads to induce physical strain on individual cells [136,246–248]	• Force induced translocation of mechanically sensitive biomolecules • Nuclei mechanoresponse •Actin cytoskeleton remodeling • Chromatin	• Allows for targeted strain on an individual cell level • Can induce targeted chromatin structure changes	• Does not provide population-based measurements • Requires use of special equipment