Nanoscale Strain Gauges on Flexible Polymer Substrates

Biological cell force is important for proper cell and tissue function and can be an indicator of disease.  Therefore, measuring cell force has potential in disease diagnosis and treatment.  However, biological cell force measurement approaches are limited and typically slow due to the analysis of optical images, before and after cell application or other methods that have low throughput. Recent research by Devin Brown, Isha Lodhi, Biya Haile, David Myers, Wilbur A. Lam, and Oliver Brand seeks to overcome this bottleneck by the development of nanoscale strain gauges.  

These nanoscale strain gauges can measure cell forces as an electrical signal in real time and have the potential to be scaled to measure tens of thousands of cells simultaneously. Strain gauges with 100 nm dimensions in soft PDMS polymer were used to measure strain applied to the PDMS surface. Compressive strain ranging from 0.4 to 1.7% in the PDMS surface, corresponding to forces of 718 nN to 2.0 µN were detected with resistance changes of 1% to 8%. These strain gauges are a promising new approach for biological cell force measurement.

The work was performed in part at the Georgia Tech Institute for Electronics and Nanotechnology (IEN) using an STS-Elionix ELS-G100 electron beam lithography system. The IEN is part of the National Nanotechnology Coordinated Infrastructure (NNCI), supported by the National Science Foundation, an integrated networked partnership of user facilities serving the needs of nanoscale science, engineering, and technology.

fabricated_PDMS_sample of nanoscale strain gauges

Image: (Left) Nanoscale strain gauges on a flexible PDMS substrate held by tweezer. (Right) Scanning electron micrograph image of nanoscale strain gauge.

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