KTH designs device to sort cells by elasticity properties

14 July 2014

Researchers at Sweden's KTH The Royal Institute of Technology have used computational simulations to propose a microfluidic device that would sort cells according to their elasticity. This could offer a more reliable alternative for detecting disease biomarkers.

Chemical properties don’t give pathologists the full picture of a disease. Two cells can have very similar chemical properties, but different physical properties. Size, shape and elasticity, or deformability, are important attributes that can be also enable cell sorting, given the right kind of device.

Dhrubaditya Mitra, Assistant Professor in theoretical physics at NORDITA, Nordic Institute of Theoretical Physics at KTH and Stockholm University, offers an example of why elasticity matters. If you are infected with malaria, the physical nature of your red blood cells changes, he says. “They become harder. And red blood cells also become harder as they get older too. These harder red blood cells are filtered by the spleen which acts like a sieve. The softer red blood cells can squeeze through the gaps but the harder ones cannot.”

Consisting of a duct embedded with a semi-cylindrical obstacle, and a diffuser, a microfluidic device works in a similar fashion. Several kinds of microfluidic devices have been fabricated to detect biophysical markers. But the big challenge has been in designing the geometries that allow for efficient cell sorting, according to team leader Luca Brandt, a professor of fluid mechanics at KTH.

Visualization from a numerical simulation of a cell flowing 
past the obstacle through the microfluidic device.
Visualization from a numerical simulation of a cell flowing
past the obstacle through the microfluidic device.

The design was proposed by the researchers at KTH Linne FLOW Centre and SeRC (Swedish e-Science Centre). Their work draws on numerical techniques and computational capabilities developed in the last decade to handle the complexity of microscale flows. The research was published in the Royal Society of Chemistry’s journal, Soft Matter [1].

“A particular novelty of our work is that this design process has not been done in a laboratory but as a computer simulation,” Brandt says, comparing their computer simulations to the early stages of aircraft or vehicle design. “We hope that our work will bring such a change to design of microfluidic devices, too.”


1. Lailai Zhu, Cecilia Rorai, Dhrubaditya Mitra and Luca Brandt. A microfluidic device to sort capsules by deformability: A numerical study. Soft Matter, 2014. DOI: 10.1039/C4SM01097C
First published online 20 Jun 2014.


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