IBM Making Silicon to Sort Viruses and Other Nanoscale Biological Targets

It’s long been understood that early disease detection is the key to successful treatments. But annual checkups with a doctor might not be frequent enough to help. So imagine if you could forego a trip to the doctor’s office and detect any disease with a simple urine or saliva test at home.

Of course this has been the aim of lab-on-a-chip technologies for years now, but now scientists at IBM Research may have tipped the scales in the technology that could make such at-home tests real.

In cross-disciplinary research described in the journal Nature Nanotechnology, a team at IBM led by research scientist Joshua Smith and Gustavo Stolovitzky, program director of IBM Translational Systems Biology and Nanobiotechnology, has been able to retool silicon-based technologies to create a diagnostic device that can separate viruses, DNA, and other nanoscale-size biological targets from saliva or urine. This could enable the device to detect the presence of diseases before any physical symptoms are visible.

Of course, the separation of nanoscale particles has been possible for years in various forms, such as ultracentrifugation, gel electrophoresischromatography, or filtration. These approaches all come with compromises: Centrifugation and chromatography can be very precise but require expensive machinery and trained technicians; gels and filter media are cheap and easy to use but are less precise and more difficult to recover samples from.

The basis of the IBM team’s approach is something called deterministic lateral displacement (DLD) separation technology, which was first developed in 2004. DLD is a microfluidic process that uses the laminar flow of fluid through a field of tiny posts to separate particles based on size. In this array of pillars, the separation occurs because the smaller particles are moving in the direction of the fluid, while the larger particles get deflected along the direction of pillar asymmetry. This sorting makes it possible to isolate,…[Read more]