LAKE WALES, Fla.—IBM Research (Yorktown Heights, N.Y.) has designed a microfluidic lab-on-a-chip that can separate biological particles down to sizes as small as 20-nanometers. If successful, the chip will make it possible to detect cancer markers before a tumor has even started to grow. The Mount Sinai Ichan School of Medicine (Manhattan, New York) is collaborating with IBM on the project.
IBM Nanobiotechnology Lab's Josh Smith, an IBM research scientist, demonstrates nanoscale deterministic lateral displacement (DLD) pillar arrays for microfluidic labs-on-a-chip.
“The idea is to take a fluid sample—a blood sample or a urine sample—to be used for diagnostic purposes, separate out the materials within the sample with very very fine resolution,” said Josh Smith, an IBM research scientist and silicon fabrication expert at IBM's Thomas J Watson Research Center (see video above). “A lot of people are sorting at the cellular level, but we are separating at a scale of 2-to-3 orders of magnitude [100 to 1000 times] below that limit where we are at the true nanoscale, separating interesting materials like exosomes, DNA [deoxyribonucleic acid], proteins et cetera.”
These ultra-small materials at the sub-cellular level form before a cell goes cancerous, potentially allowing practitioners to head-off cancer before it even materializes in a tumor. Currently IBM is separating materials as small as 20-nanometers in size, whereas human cells are on-average 10-microns, thus allowing advance notice of cancer. Previously, physicians had to wait until the cancer cells started making the tumor before they could be detected with current lab equipment.
Not only will IBM's lab-on-a-chip be better at early detection, according to collaborating physicians at Mount Sinai, but is also faster than current methods. It can also be made portable for point-of-care detection, is easier to use and requires significantly less volume of fluid, say a few drops of blood instead of a whole vial full. IBM's goal is to add to its current microfluidic separator all the other electronic components necessary to perform the complete analyses of a full-scale lab, only at the nanoscale.
The key to IBM's success, it claims, is its novel deterministic lateral displacement (DVD) approach to sorting. Instead of forcing materials through different sized sieves—which slows down the material flow to a stop-and-go process—it builds fields of pillars with different spacing through which the fluids flow without slowing down. The smaller size gravitate straight through the pillar array, with the progressive larger sizes naturally flowing to the sides until they fit between the asymmetrical pillars that graduate to larger sizes (see video). Currently its DVD nanoscale sorting array is sized at 2-by-2 centimeters in order to catch all sized materials from individual molecules up to whole cells.
For the future, IBM is aiming to diversify the types of particles it can separate, improve its precision and begin using it in real-world applications, beginning at Mount Sinai where its first trial will be screening for prostate cancer. Exosomes, which range from 20-to-140 nanometers, are extracellular vesicles that transfer lipid, protein, and RNA cargoes between cells. They can also be used as the biomarkers for the diagnosis and prognosis of cancer, when extracted from blood, saliva or urine. Examination of the size, surface proteins and nucleic acid cargo, they carry reveals the health of the cells from which they came.
— R. Colin Johnson, Advanced Technology Editor, EE Times