Cellogram: On-the-Fly Traction Force Microscopy

Abstract

Traction Force Microscopy (TFM) derives maps of cell-generated forces, typically in the nN range, transmitted to the extracellular environment upon actuation of complex biological processes. In traditional approaches, force rendering requires a terminal, time-consuming step of cell deadhesion to obtain a reference image. A conceptually opposite approach is provided by reference-free methods, opening to the on-the-fly generation of force maps from an ongoing experiment. This requires an image processing algorithm keeping the pace of the biological phenomena under investigation. Here, we introduce an integrated software pipeline rendering force maps from single reference-free TFM images seconds to minutes after their acquisition. The algorithm tackles image processing, reference image estimation, and finite element analysis as a single problem, yielding a robust and fully automatic solution. The method's capabilities are demonstrated in two applications. First, the mechanical annihilation of cancer cells is monitored as a function of rising environmental temperature, setting a population threshold at 45°C. Second, the fast temporal correlation of forces produced across individual cells is used to map physically connected adhesion points, yielding typical lengths that vary as function of the cell cycle phase.

The cellular mechanobiology of aging: from biology to mechanics

“…Cellular traction forces are determinative for cell functionality and influence the migration, proliferation, development, and differentiation of cells in aging. Traction force microscopy (TFM), based on a fluorescent bead-embedded hydrogel substrate 165 or elastic polydimethylsiloxane (PDMS) micropillar array, 114,166 has been commonly used to measure cellular traction forces. For example, polyacrylamide hydrogel-based TFM (Fig.…”

“…4D). 105,114,166,169 When cells are cultured on PDMS micropillar arrays, the cellular contractile forces bind the micropillars underneath the cells. The deflection of the micropillars can be recorded with fluorescent dyes and live cell imaging to calculate the force exerted by the cells.…”

Microskeletal stiffness promotes aortic aneurysm by sustaining pathological vascular smooth muscle cell mechanosensation via Piezo1    

“…VSMC were cultured on the micropillar array overnight prior to mechanical stimulation and analysis. CSK contractility was analyzed by quantifying the deflection of micropillar using the Cellogram 56 and custom-developed MATLAB programs (Mathworks).…”

SiO2‐Decorated Parylene C Micropillars Designed to Probe Cellular Force

“…Recently developed tools to quantify the traction force generated by cells range from microscopy to molecular force sensors. [ 6–11 ] All these techniques possess some advantages and disadvantages [ 12 ] and offer a variety of mechanisms through which cells can move, divide, remodel, differentiate, communicate, and sense their microenvironment. [ 13 ]…”