Purdue researchers have developed a biosensor that could detect cancer early and design personalized medicine based on a patient’s specific biochemistry.
The device, called a Flexure-FET biosensor, combines a mechanical sensor that identifies a bio-molecule based on its mass and size with an electrical sensor that identifies molecules based on their electrical charge, according to a Purdue University press release. Researchers claim the device could be several hundred more times more sensitive than other biosensors.
“Individually, both of these types of biosensors have limited sensitivity, but when you combine the two you get something that is better than either,” says Muhammad A. Alam, a Purdue University professor of electrical and computer engineering. The research’s findings are published in the Proceedings of the National Academy of Sciences.
The sensor detects both charged and uncharged bio-molecules, allowing a broader range of applications than either type of sensor alone. One application is in personalized medicine, in which the sensor records an inventory of proteins and DNA from individual patients so that doctors can make more precise diagnostics and treatment decisions.
This medical device also could be deployed to detect cancer and other diseases earlier than other similar tools. The device has this advantage because it can detect small quantities of DNA fragments and proteins deformed by cancer long before the disease is visible through imaging and other methods, Alam says.
The sensor uses a vibrating cantilever, a sliver of silicon that resembles a tiny diving board. The university explains further how the device works:
Located under the cantilever is a transistor, which is the sensor’s electrical part. In other mechanical biosensors, a laser measures the vibrating frequency or deflection of the cantilever, which changes depending on what type of biomolecule lands on the cantilever. Instead of using a laser, the new sensor uses the transistor to measure the vibration or deflection. The sensor maximizes sensitivity by putting both the cantilever and transistor in a ‘bias.’ The cantilever is biased using an electric field to pull it downward as though with an invisible string.
“This pre-bending increases the sensitivity significantly,” says Ankit Jain, a graduate student who helped write the paper. The device can be made to detect almost any molecule as long as the sensor is configured property, Alam adds. The university has applied for a patent.
Source: “Ultrasensitive Biosensor Promising for Medical Diagnostics,” Purdue University press release, 5/14/12
Image by Purdue University, used with permission.
Dale McGeehon has been a journalist and editor for more than 25 years, covering chemical regulation and testing for Pesticides and Toxic Chemical News and innovations in material sciences for the National Technology Transfer Center. His writing credits include Omni and College Park magazines and The New York Times.