Custom-Built Optical Tweezers for Locally Probing the Viscoelastic Properties of Cancer Cells

Abstract

We report a home built optical tweezers setup to investigate the mechanism of the membrane tether formation from single cells in vitro. Using an optically trapped microbead as probe, we have determined the force-elongation curve during tether formation and extracted several parameters characterizing the viscoelastic behavior of the cell membrane: tether stiffness, force, and viscosity. Breast cancer MDA-MB-231 cells have been studied in two different conditions, at room and physiological temperatures, showing a strong temperature dependence of the visoelastic properties of the cell membrane. To get detailed inside information about the tether formation mechanism we have extended the analysis of the force-elongation curves fitting them with a Kelvin model. These preliminary results are part of a larger project of whose goal is to compare the viscoelastic properties of several types of cancer cell lines, characterized by different aggressiveness and metastatic potential.

Keywords:

• cancer tumor cell
• cell biomechanics
• force spectroscopy
• membrane viscoelasticity
• optical tweezers microscopy

ACKNOWLEDGMENTS

This work is supported partially by the MIUR (Italian Ministry of University and Research), Project: Cell mobility and metastatic spreading: A study on human neoplastic cells using Optical Tweezer. Federica Tavano acknowledges the grant from MIUR and Giulietta Pinato the financial support from the EU Project Nanoscale 214566.