A resonant structure designed for probing the elastic properties of suspension and adherent cells in liquid environments

This paper presents a novel force sensitive structure exploiting a dynamic mode for probing the elastic properties of living cells. A key feature of this structure is the possibility to conduct measurements in liquid environments while keeping high dynamic performances. The structure indeed provides a steady area that can be adapted so that suspension or adherent cells can be placed in culture medium. The steady area is also connected to two adjacent beam resonators. Because these resonators never need to be immersed into the culture medium during measurements, forces applied to cells can be estimated with a high sensitivity via frequency shifts. In this paper, we conduct an extensive theoretical analysis to investigate the nonlinear effects of large static predeflections on the dynamic behavior of the structure. As a proof of concept, we also report the fabrication, characterization and calibration of a first prototype intended to deal with suspension cells with a diameter ranging from 100 to 500 μm. This prototype currently offers a quality factor of 700 and a force sensitivity of ∼2.6 Hz/mN. We also demonstrate that the prototype is capable of measuring the elastic modulus of biological samples in a rapid and sufficiently accurate manner without the need of a descriptive model. PACS numbers: 87.85.fk, 87.17.Rt, 46.70.De, 62.40.+i ‡ The final version of this paper has been published in Journal of Micromechanics and Microengineering by IOP Publishing Ltd and is available at http://iopscience.iop.org/0960-1317/22/11/115033/ (doi: 10.1088/0960-1317/22/11/115033). Please, cite this article as: J. Micromech. Microeng. 22 (2012) 115033. ha l-0 07 45 07 7, v er si on 1 24 O ct 2 01 2 Author manuscript, published in "Journal of Micromechanics and Microengineering 22 (2012) 115033" DOI : 10.1088/0960-1317/22/11/115033