Evaluating Bulk Stiffness of MCF-7 Cells using Micro-scale Composite Compliant Mechanisms

Bhargav, Santosh DB and Jorapur, Nikhil and Ananthasuresh, GK (2013) Evaluating Bulk Stiffness of MCF-7 Cells using Micro-scale Composite Compliant Mechanisms. In: Proceedings of the 1st International and 16th National Conference on Machines and Mechanisms (iNacoMM 2013), December 18-20, 2013.

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Abstract

Biomechanical assays offer a good alternative to biochemical assays in diagnosing disease states and assessing the efficacy of drugs. In view of this, we have designed, fabricated and tested a miniature compliant tool to estimate the bulk stiffness of cells, particularly MCF-7 (Michigan Cancer Foundation) cells. The compliant tool comprises a gripper and a Displacement-amplifying Compliant Mechanism (DaCM), where the former helps in grasping the cell and the latter enables vision-based sensing of force. A DaCM is necessary because the field of view of a microscope at the required magnification is not large enough to simultaneously observe the cell and a point on the gripper that move sufficiently to estimate the force. Therefore, a DaCM is strategically embedded within an existing gripper design leading to a composite compliant mechanism. The DaCM is designed using the inetoelastostatic map technique to achieve a resolution 42 nN. The gripper, microfabricated with SU-8 polymer using photolithography, is within the footprint of about 10 mm by 10 mm with the smallest feature size of about 5 microns. The gripper was tested in air and was found to be satisfactory in grasping and squeezing objects as small as 15 microns in size. However, testing in aqueous medium encountered an unanticipated problem due to buoyancy, which curled the jaws of the gripper up by as much as 40 microns and thus losing contact with the cell that is to be grasped. A design modification is suggested to fix this problem.

Item Type:	Conference Proceedings
Series.:	Proceedings of the 1st International and 16th National Conference on Machines and Mechanisms (iNacoMM 2013)
Publisher:	International and National Conference on Machines and Mechanisms (iNacoMM)
Additional Information:	Copy right for this article belongs to the International and National Conference on Machines and Mechanisms (iNacoMM)
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	30 Aug 2016 10:31
Last Modified:	30 Aug 2016 10:31
URI:	http://eprints.iisc.ac.in/id/eprint/54629

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