Figure 3
MyoTACTIC enables non-invasive and in situ measurement of hMMT contractile force. (a) Phase-contrast images of a micro-post (outlined in yellow dashed lines) displaced in response to the force exerted by a microwire (outlined in white dashed circles). Scale bar 500 µm. (b) Plot depicting the relation between force and displacement of micro-posts fabricated using two different PDMS compositions (curing agent weight (wt): monomer weight), as measured by the Microsquisher. (c) Bar graph quantification of the average force/displacement ratio for the micro-posts formed using two different PDMS compositions. ***p < 0.001 (n = 10 micro-posts per condition). (d) Representative line graph traces of the micro-post displacement during high frequency (20 Hz) electrical stimulation of hMMTs at Day 7, 10, and 14 of differentiation measured by the custom-written Python computer vision script. (e,f) Bar graph quantification of the absolute (e) and specific (f) tetanus contractile forces generated by hMMTs at Day 7, 10, and 14 of differentiation. *p < 0.05 (n = minimum of 11 hMMTs from 4 muscle patient donors per time point). In (e,f) each symbol represents averaged hMMT data from one patient donor. In (c,e,f) values are reported as mean ± SEM. Significance was determined by t-test in (c) or Friedman test followed by Dunn’s multiple comparisons test to compare differences between groups in (e,f).
