This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A programmable microfluidic device developed at the Institute of Science Tokyo, Japan, combines deterministic lateral displacement, a microfluidic technique used to separate particles according to size, with temperature-responsive polymer micropillars to dynamically change separation conditions along a single channel. Using this device, researchers successfully separated multiple particle populations.
Additionally, they efficiently isolated viable cancer cells, white blood cells and red blood cells from diluted whole blood. Biological samples comprise multiple cells and particles that vary in size, shape and properties. Separation of such fractions from biological samples is the foundation of fields such as biomedical research, diagnostics and cell-based therapeutics.
However, samples such as blood contain cells with overlapping sizes, making it difficult to isolate multiple fractions. Conventional microfluidic separation systems often rely on fixed separation thresholds and require multiple devices to isolate all fractions. To fill this gap, a research team from the Institute of Science Tokyo (Science Tokyo), Japan, developed a spatially programmable deterministic lateral displacement (DLD) system using temperature-responsive polymer micropillars within the DLD array.
The team was led by professor Takasi Nisisako from the Cutting-edge Biomedical Engineering Research Center, Institute of Biomedical Engineering, and the Laboratory for Future Interdisciplinary Research of Science and Technology, Institute of Integrated Research, Science Tokyo. He was joined by assistant professor Yusuke Kanno from the Laboratory for Future Interdisciplinary Research of Science and Technology, Institute of Integrated Research, and graduate student Ze Jiang from the Department of Mechanical Engineering, School of Engineering, Science Tokyo. Their study, published online July 29, 2026, in Lab on a Chip, demonstrates how a single DLD array can be programmed for different separation conditions at different positions along a single microfluidic channel by controlling the temperature across the array.
DLD is a well-known technique that separates particles according to their size as they flow through a series of microscopic pillars arranged in an offset pattern. Particles larger than the critical diameter (the size threshold for migration) are repeatedly pushed sideways by the pillars in bump mode, while smaller particles follow the inter-pillar gaps in a zigzag fashion. In conventional DLD systems, this threshold is fixed by the pillar geometry.
In contrast, the new system contains temperature-responsive poly(N-isopropylacrylamide), or PNIPAM, polymer pillars that allow the threshold to be regulated. "PNIPAM hydrogel changes its volume with temperature. At lower temperatures, the micropillars swell and narrow the gaps between them; at higher temperatures, they shrink and widen the gaps," Nisisako explains.
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