Table 1.

Overview of biomechanical methods used in Xenopus embryos

Method and reference	Schematic	Overview	Mechanical property measured	Tissue studied	Quantitative?	Destructive?
Tissue dissection (Beloussov et al., 1975)		Tissue cut with blade and immediate deformation observed	Map location and direction of mechanical stresses in embryo	Whole embryo	No	Yes
Laser Ablation (Hara et al., 2013)		Wound tissue with laser and record recoil velocity	Map location and direction of mechanical stresses in embryo	Whole embryo or expant	No	Yes
Strain mapping (Kim et al., 2014; Feroze et al., 2015; Yamashita et al., 2016)		Observation of movement and deformation of cells in tissue allows forces to be inferred	Map location and direction of mechanical stresses in embryo and/or estimate the distance a mechanical signal propogates	Whole embryo or expant	No	No
FRET-based tension sensor (Yamashita et al., 2016)		Measure FRET around an elastic linker within protein that can experience tension.	Tension at the molecular level	Whole embryo	No	No
nNewton Force Measurement (Moore et al., 1995; Davidson and Keller, 2007)		Tissue explant uniaxially compressed against a cantilever	Viscoelastic properties of explant	Brick shaped explant	Yes	Explant cut
Microaspiration (von Dassow et al., 2010)		Measure length of tissue drawn into a channel of known diameter under negative pressure	Viscoelastic properties of embryo	Whole embryo	Yes	No
Axisymmetric drop shape analysis (Kalantarian et al., 2009; Luu et al., 2011; David et al., 2014)		Measure deformation of an explant or cellular aggregate over time	Surface tension of the explant or aggregate	Explant or cellular aggregate	Yes	Yes
Cantilever based measurement of migration force (Hara et al., 2013)		A migrating explant pushes against a cantilever	Force produced during explant migration	Leading edge mesoderm explant	Yes	Explant cut
Insertion of cantilevers into embryo (Feroze et al., 2015)		Morphogenetic movements of blastopore closure push directly on inserted cantilever	Force produced during blastopore closure	Whole embryo	Yes	No
Tractor pull assay (Pfister et al., 2016)		Covergence and extension of explant pulls on sled and moves cantilever	Force produced during convergence and extension	Giant explant	Yes	Explant cut
3D Force Microscopy (Zhou et al., 2015)		Force produced by explant embedded in gel measured by fluorescent bead displacement.	Force produced during morphogenetic movements	Dorsal explant	Yes	Explant cut