Polyacrylamide Bead Sensors for in vivo Quantification of Cell-Scale Stress in Zebrafish Development

Abstract

Mechanical stress exerted and experienced by cells during tissue morphogenesis and organ formation plays an important role in embryonic development. While techniques to quantify mechanical stresses in vitro are available, few methods exist for studying stresses in living organisms. Here, we describe and characterize cell-like polyacrylamide (PAAm) bead sensors with well-defined elastic properties and size for in vivo quantification of cell-scale stresses. The beads were injected into developing zebrafish embryos and their deformations were computationally analyzed to delineate spatio-temporal local acting stresses. With this computational analysis-based cell-scale stress sensing (COMPAX) we are able to detect pulsatile pressure propagation in the developing neural rod potentially originating from polarized midline cell divisions and continuous tissue flow. COMPAX is expected to provide novel spatiotemporal insight into developmental processes at the local tissue level and to facilitate quantitative investigation and a better understanding of morphogenetic processes.

Microparticle traction force microscopy reveals subcellular force exertion patterns in immune cell–target interactions

“…Moreover, we have shown that NATURE COMMUNICATIONS | https://doi.org/10.1038/s41467-019-13804-z ARTICLE the dynamics of such processes can be captured using live cells and time-lapse microscopy, and can be correlated with cellular protein distributions. As also exemplified by the development of an analogous approach for quantifying forces during development in zebrafish embryos by Träber et al 40 , the method presented here is expected to be broadly applicable in the study of inter-and intracellular forces in vitro and in vivo.…”

“…Bulk modulus measurements. Bulk modulus measurements were performed as described previously 40,44 . Briefly, dextran solutions with known osmotic pressure 45 were made from FITC-conjugated dextran (molecular weight: 2 × 10 6 g/mol, Mil-liporeSigma 52471).…”

Superresolved microparticle traction force microscopy reveals subcellular force patterns in immune cell-target interactions

“…As also exemplified by the development of an analogous approach for quantifying forces during development in zebrafish embryos by Träber et al 36 , the method presented here is expected to be broadly applicable in the study of inter-and intracellular forces in vitro and in vivo.…”

Global and local tension measurements in biomimetic skeletal muscle tissues reveals early mechanical homeostasis

“…To determine the local tension in the muscle tissue, we implemented elastic hydrogel beads as tension sensors, an approach first used by others in different systems [13,28,53,55]. We custom-made elastic PAA beads by a water in oil emulsion approach ( Figure 3A).…”

“…Despite this, non-destructive experimental approaches to investigate spatial and temporal forces on a cellular level are limited and thus, characterization of local cell niches within a tissue remains a challenge. To overcome this problem, Campas et al introduced 2/23 biocompatible oil microdroplets to evaluate cell-generated forces in living tissue for the first time [10] and very recently, deformable PAA beads were used to determine local tension on a cell scale within cancer spheroids, zebrafish embryos and during phagocytosis [13,28,53,55]. Contrary to oil microdroplets, PAA beads are compressible and are therefore able to reveal isotropic tissue pressure.…”