Working with support of the Bill & Medlinda Gates Foundation’s Grand Challenge to develop field-worthy point-of-care diagnostics for the developing world, a couple of Cornell researchers are mashing up their individual inventions to create a handheld pathogen detector that can quickly diagnose pathogens ranging from chlamydia and tuberculosis to HIV.
The portable device is a blend of a synthetic DNA tagging technology developed by Cornell biological and environmental engineering prof Dan Luo and a CMOS chip developed by Edwin Kan, an electrical and computer engineering professor. Luo’s technology does the actual detecting, while Kan’s chip is able to identify and respond to the amplified signals generated by the sensor. The result: a handheld disease targeting machine that can diagnose pathogens in half an hour rather than days.
The sensor works via Y-shaped segments of synthetic DNA that Luo’s research group devised. At the bottom of the Y the team installed antibody designed to target and lock onto a certain pathogen. On one of the upper arms it placed a molecule that will link up with other similar molecules in the presence of UV light. In practice, two slightly different Y-structures are introduced to a sample, where they attach themselves to opposite sides of any target pathogen molecule they come in contact with. But tiny strands of Y-shaped DNA attaching themselves to a single molecule doesn’t send a very strong signal--the entire combined structure is still so small that only highly tuned and very precise sensors or microscopes could detect that the DNA had attached itself to the pathogen at all.