  Movies of human induced pluripotent stem cell (hiPSC)-derived engineered
cardiac tissue (microbundles) contain abundant information about structural and
functional maturity. However, extracting these data in a reproducible and
high-throughput manner remains a major challenge. Furthermore, it is not
straightforward to make direct quantitative comparisons across the multiple in
vitro experimental platforms employed to fabricate these tissues. Here, we
present "MicroBundlePillarTrack," an open-source optical flow-based package
developed in Python to track the deflection of pillars in cardiac microbundles
grown on experimental platforms with two different pillar designs ("Type 1" and
"Type 2" design). Our software is able to automatically segment both pillars,
track their displacements, and output time-dependent metrics for contractility
analysis, including beating amplitude and rate, contractile force, and tissue
stress. Because this software is fully automated, it will allow for both faster
and more reproducible analyses of larger datasets and it will enable more
reliable cross-platform comparisons as compared to existing approaches that
require manual steps and are tailored to one specific experimental platform. To
complement this open-source software, we share a dataset of 1,540 brightfield
example movies on which we have tested our software. Through sharing this data
and software, our goal is to directly enable quantitative comparisons across
labs, and facilitate future collective progress via the biomedical engineering
open-source data and software ecosystem.
