Cell size and actin architecture determine force generation in optogenetically activated cells

Light-driven biological actuators to probe the rheology of 3D microtissues

“…As previously described, ArhGEF11 was recruited to the cell membrane upon blue light stimulation, thus activating RhoA and subsequently cell contractility (Fig. 1c) 19,20 . We embedded these opto-RhoA fibroblasts in a neutralized collagen I solution within microfabricated PDMS wells containing two T-shaped microcantilevers.…”

“…Gates were chosen such that fluorescence levels in GFP and mCherry channels were approximately 100 times higher than in control WT cells. The obtained opto-RhoA fibroblasts 20,48 (<15 passages, kindly provided by L. Valon and M. Coppey, Institute Curie, Paris, France) were cultured in Dulbecco's modified Eagle's medium (DMEM, Gibco Invitrogen) supplemented with 10% fetal bovine serum (FBS, Gibco Invitrogen), 100 U/ml of penicillin and 100 µg/ml of streptomycin (Gibco Invitrogen), and kept at 37 °C in an atmosphere Article https://doi.org/10.1038/s41467-023-36371-w saturated in humidity and containing 5% CO2. Collagenase experiments performed by incubating microtissues with 0.05 g/L of collagenase type I (Sigma) for 10 min before thorough rinsing with PBS and with growth medium.…”

“…Thanks to its spatial and temporal resolution, optogenetics has emerged as a powerful tool for spatiotemporally controlling cell signaling 17 . Using optogenetic control of RhoA activity, several studies recently used light pulses to locally up-or down-regulate cell-generated forces [18][19][20] . Valon et al further demonstrated that these changes in cellular tension were paralleled by tissue deformations in 2D epithelial monolayers 19 , suggesting an exciting avenue for using cells as mechanical actuators.…”

A multiscale approach to assess thermomechanical performance and force generation in nanorobotic microgels

“…This approach enabled investigations into the influence of geometrical and mechanical properties of 3D hydrogel networks, which have been used to design active biomaterials in an efficient manner by significantly reducing the number of experimental parameters to be tested. 3,5,6 On the other hand, integrating photothermally powered actuators in cell culture systems requires tuning of generated heat loads to avoid excessive heating, which may cause cell damage in extreme cases. At the millimeter scale, the temperature output of optical actuators could be directly measured using infrared imaging and standard thermometry.…”

“…This approach enabled investigations into the influence of geometrical and mechanical properties of 3D hydrogel networks, which have been used to design active biomaterials in an efficient manner by significantly reducing the number of experimental parameters to be tested. 3,5,6…”