Ultrafast viscosity measurement with ballistic optical tweezers

Lightning-speed measurements of stickiness

30 September 2021

The viscosity, or stickiness, of a liquid can be measured about 1,000 times faster than previously, providing researchers with a unique window for exploring the inner workings of biological cells.

The viscosity of is a key fluid property. The ability to measure it inside cells would provide new insights and could help to diagnose diseases such as cancer. But conventional ways are far too slow to be useful.

Now, seven researchers at The University of Queensland in Australia have measured viscosity with a time resolution about 20 microseconds by tracking the motions of small particles suspended in a laser beam.

The secret to their success was a novel detection method that enabled them to block out the light used to trap the particle and to detect just the weak light scattered from it.

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References

1. Nature Photonics 15, 386–392 (2021). doi: 10.1038/s41566-021-00798-8