Design and Fabrication by Thermal Imprint Lithography and Mechanical Characterization of a Ring-Based PDMS Soft Probe for Sensing and Actuating Forces in Biological Systems

In this paper, the design, fabrication and mechanical characterization of a novel polydimethylsiloxane (PDMS) soft probe for delivering and sensing forces in biological systems is proposed. On the basis of preliminary finite element (FEM) analysis, the design takes advantage of a suitable core geometry, characterized by a variable spring-like ring. The compliance of probes can be finely set in a wide range to measure forces in the micronewton to nanonewton range. In particular, this is accomplished by properly resizing the ring geometry and/or exploiting the mixing ratio-based elastic properties of PDMS. Fabrication by the thermal imprint lithography method allows fast and accurate tuning of ring sizes and tailoring of the contact section to their targets. By only varying geometrical parameters, the stiffness ranges from 1080 mNm−1 to 50 mNm−1, but by changing the base-curing agent proportion of the elastomer from 10:1 to 30:1, the stiffness drops to 37 mNm−1. With these compliances, the proposed device will provide a new experimental tool for investigating force-dependent biological functions in sensory systems.

The Case

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The Case

To submit a case that has been reviewed by an ethics committeeor to submit articles on related topics in clinical ethics, readers are invited to contact section editor Ruchika Mishra at [email protected].

The Case: A Son’s Request to Forgo Treatment

To submit a case that has been reviewed by an ethics committee or to submit papers on related topics in clinical ethics, readers are invited to contact section editor Ruchika Mishra at [email protected].