Numerical model could improve performance of cell-sorting devices by predicting paths

November 17, 2011
Deformable cells can squeeze between narrow gaps in a bump array of micropillars, leading to unpredictable paths in cell sorting devices. Copyright : A*STAR

The ability to separate cells according to size and shape is useful in biological studies. One popular method of cell sorting involves the use of microfluidic devices consisting of a series of aligned micropillars. Such ‘bump arrays’ operate on the basis of allowing cells that are small enough to pass through narrow gaps, while cells that are too large undergo lateral displacement by bumping into the pillars. Blood samples, for example, can be separated into platelets, white cells and red cells using this technique. However, some particles that have deformable as opposed to rigid structures are prone to becoming ‘mis-sorted’, as they can bypass normal routes through the devices (see image).

Keng Hwee Chiam and co-workers at the A*STAR Institute of High Performance Computing have now completed a numerical study modeling ‘dispersive’ routes made in by deformable particles. “We wanted to arrive at an understanding of how cell deformability affects the device geometry and functioning, and hence help other researchers to optimize their devices in the future,” says Chiam.

The researchers created a two-dimensional to examine the different possible routes taken by cells through the device . In experimental observations, rigid cells either follow a zigzag pattern through the pillars, or they bump into the pillars and drop to the bottom of the array, depending on their size. The new computer model can accurately predict these paths.

In addition, the model can predict paths taken by large cells or particles that can change shape and squeeze through the pillars. These were found to follow a far more random path, sometimes moving in zigzag directions, sometimes bumping into the pillars, and sometimes getting stuck completely. These so-called ‘dispersive trajectories’ are dependent on the orientation, arrangement and size of the pillars present in the device. Chiam explains, “This shows us what design parameters to avoid, and we imagine that numerical simulations, such as the ones used by the aerospace industry in aircraft design, could benefit future biological technologies.”

The simulations could be improved by extending the computer model to a full three-dimensional representation of the cells and micropillars, but amassing the computational data required is currently cost-prohibitive. Chiam hopes, however, that future collaborations will lead to a three-dimensional version of the model and adds that the research team aims “to simulate the sorting of DNA strands instead of , to see if they can be sorted according to their length and sequence.”

Explore further: Nanopillars significantly boost the power conversion efficiency of thin-film solar cells

More information: Quek, R., Le, D. V. & Chiam, K.-H. Separation of deformable particles in deterministic lateral displacement devices. Physical Review E 83, 056301 (2011).

Related Stories

Nanomaterials: Pillars of the assembly

September 29, 2011

The ever-increasing demand for enhanced performance in electronic devices such as solar cells, sensors and batteries is matched by a need to find ways to make smaller electrical components. Several techniques have been proposed ...

Recommended for you

Study suggests fish can experience 'emotional fever'

November 25, 2015

(—A small team of researchers from the U.K. and Spain has found via lab study that at least one type of fish is capable of experiencing 'emotional fever,' which suggests it may qualify as a sentient being. In their ...

A huge chunk of a tardigrade's genome comes from foreign DNA

November 23, 2015

Researchers from the University of North Carolina at Chapel Hill have sequenced the genome of the nearly indestructible tardigrade, the only animal known to survive the extreme environment of outer space, and found something ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.