Abstract

mechano- and visco-NPS: An Electronic Method to Measure the Mechanical Properties of Cells

Lydia Sohn, Professor, Department of Mechanical Engineering, University of California, Berkeley

We have developed an efficient, label-free method of screening cells for their phenotypic profile, which we call Node-Pore Sensing (NPS).  NPS involves measuring the modulated current pulse caused by a cell transiting a microfluidic channel that has been segmented by a series of inserted nodes.  Previously, we showed that when segments between the nodes are functionalized with different antibodies corresponding to distinct cell-surface antigens, immunophenotyping can be achieved.  In this talk, I will show how we have significantly advanced NPS by simply inserting between two nodes a “contraction” channel through which cells can squeeze.  “Mechano-NPS”, as we now call our method, can simultaneously measure a cell’s size, resistance to deformation, transverse deformation, and ability to recover from deformation.  As I will show, mechano-NPS can distinguish malignant from non-malignant epithelial cells and discriminate between sub-lineages and, excitingly, chronological age groups of primary human mammary epithelial cells.  Moreover, mechano-NPS can track malignant progression.  By replacing the contraction channel with one that is sinusoidal in shape, we can measure the viscoelastic properties (elasticity and viscosity) of cells.  I will show how “visco-NPS” can quantify the mechanical transitions of cells as they traverse the cell cycle or are initiated into an epithelial-mesenchymal transition.