Scientists have developed a new lab-on-a-chip technology that can, for the first time, separate biological particles at the nanoscale level and could help enable physicians to detect diseases such as cancer before symptoms appear. As reported online on August 1, 2016, in the journal Nature Nanotechnology, the IBM team’s results show size-based separation of bioparticles down to 20 nanometers (nm) in diameter, a scale that gives access to important particles such as DNA, viruses, and exosomes. According to the article abstract, “Exosomes, a key target of ‘liquid biopsies,’ [which] are secreted by cells and contain nucleic acid and protein information about their originating tissue. One challenge in the study of exosome biology is to sort exosomes by size and surface markers. We use manufacturable silicon processes to produce nanoscale DLD (nano-DLD) arrays of uniform gap sizes ranging from 25 to 235 nm. We show that at low Péclet (Pe) numbers, at which diffusion and deterministic displacement compete, nano-DLD arrays separate particles between 20 to 110 nm based on size with sharp resolution. Further, we demonstrate the size-based displacement of exosomes, and so open up the potential for on-chip sorting and quantification of these important biocolloids.” Once separated, these particles can be analyzed by physicians to potentially reveal signs of disease even before patients experience any physical symptoms and when the outcome from treatment is most positive. The new article is titled “Nanoscale Lateral Displacement Arrays for Separation of Exosomes and Colloids Down to 20 nm.” Until now, the smallest bioparticle that could be separated by size with on-chip technologies was about 50 times or larger, for example, separation of circulating tumor cells from other biological components.
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