Volume 11 Issue 3
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 and Nicola P. Belfiore
1Department of Computer, Control, and Management Engineering Antonio Ruberti, University of Rome La Sapienza, Via Ariosto 25, I-00185 Roma, Italy
2MNF – Micro nano fabrication and characterization Facility, Fondazione Bruno Kessler (FBK), Via Sommarive 18, I-38123 Trento, Italy
3Head of Steering Committee of University Research and Innovation Center, Óbuda University, 96/b Becsi ut, H-1034 Budapest, Hungary
4Department of Industrial Engineering, University of Trento, via Sommarive, 9-38123 Trento, Italy
5ProM Facility, Trentino Sviluppo S.p.A., Via Zeni Fortunato, 8, 38068 Rovereto, Italy
6Department of Engineering, Universita degli Studi Roma Tre, via della Vasca Navale 79, 00146 Roma, Italy
*Author to whom correspondence should be addressed.
Abstract
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.
Keywords:MEMS; tweezers; control; viscous coefficient; soft tissue