Micromachines (Dec 2017)

New MEMS Tweezers for the Viscoelastic Characterization of Soft Materials at the Microscale

  • Paolo Di Giamberardino,
  • Alvise Bagolini,
  • Pierluigi Bellutti,
  • Imre J. Rudas,
  • Matteo Verotti,
  • Fabio Botta,
  • Nicola P. Belfiore

DOI
https://doi.org/10.3390/mi9010015
Journal volume & issue
Vol. 9, no. 1
p. 15

Abstract

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As many studies show, there is a relation between the tissue’s mechanical characteristics and some specific diseases. Knowing this relationship would help early diagnosis or microsurgery. In this paper, a new method for measuring the viscoelastic properties of soft materials at the microscale is proposed. This approach is based on the adoption of a microsystem whose mechanical structure can be reduced to a compliant four bar linkage where the connecting rod is substituted by the tissue sample. A procedure to identify both stiffness and damping coefficients of the tissue is then applied to the developed hardware. Particularly, stiffness is calculated solving the static equations of the mechanism in a desired configuration, while the damping coefficient is inferred from the dynamic equations, which are written under the hypothesis that the sample tissue is excited by a variable compression force characterized by a suitable wave form. The whole procedure is implemented by making use of a control system.

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