# Alveole Symposium 2022 – 4/4 – Ajinkya Ghagre

This is the 4/4 videos from the 2nd edition of our Virtual Symposium, featuring the last publications and results from our users in cell biology and mechanobiology.

Pattern-Based Contractility Screening, a Reference-Free Alternative to Traction Force Microscopy Methodology

The sensing and generation of cellular forces are essential aspects of life. Traction force microscopy (TFM) has emerged as a standard broadly applicable methodology to measure cell contractility and its role in cell behavior. While TFM platforms have enabled diverse discoveries, their implementation remains limited in part due to various constraints, such as time-consuming substrate fabrication techniques, the need to detach cells to measure null force images, followed by complex imaging and analysis, and the unavailability of cells for postprocessing. Here we introduce a reference-free technique to measure cell contractile work in real time, with commonly available substrate fabrication methodologies, simple imaging, and analysis with the availability of the cells for postprocessing. In this technique, we confine the cells on fluorescent adhesive protein micropatterns of a known area on compliant silicone substrates and use the cell deformed pattern area to calculate cell contractile work. We validated this approach by comparing this pattern-based contractility screening (PaCS) with conventional bead-displacement TFM and show quantitative agreement between the methodologies. Using this platform, we measure the contractile work of highly metastatic MDA-MB-231 breast cancer cells that is significantly higher than the contractile work of non-invasive MCF-7 cells. PaCS enables the broader implementation of contractile work measurements in diverse quantitative biology and biomedical applications.

Presented by: Ajinkya Ghagre, a PhD student in the Department of Bioengineering at McGill University, and a biophysicist interested in studying the role of physical forces and mechanics in regulating cell biology. He designed and developed PaCS (Pattern-based Contractility Screening), a novel tool to simplify cell contractile force measurements and utilized it to quantify contractile force changes in breast cancer cells. In the future, he aims at upgrading this tool into a high throughput cell contractile screening technology which will be used for drug validation and can potentially cut the cost for drug discovery process.