Scientists have engineered the first fully automated, all-in-one test, or "lab on a chip," that can be programmed to probe cells brushed from the mouth for a common sign of oral cancer, according to a study published in the August issue of the journal Lab on a Chip.
About one-half the size of a toaster, the portable device yields results in just under 10 minutes, or well within the duration of a routine visit to a dentist or physician. Currently, patients must undergo an often painful tissue biopsy and usually wait three days to one week for the laboratory results.
"What’s exciting is the speed and efficiency that this test will bring to the diagnostic process," said John McDevitt, PhD, a scientist at the University of Texas at Austin and the senior author on the report.
"No longer will patients need to endure referrals, long waits for test results, and scheduling follow-up consultations," said Dr. McDevitt. "Patients will get immediate results and feedback from their dentist or [physician] on how best to proceed."
The group’s proof-of-principle study showed that the test could accurately measure levels of epidermal growth factor receptor (EGFR) on three distinct types of oral cancer cells. This protein, which normally is displayed on the surface of cells, tends to be overproduced in oral tumor cells and serves as a measurable marker of oral cancer.
The researchers developed a test for oral cancer that begins with brushing cells from a suspicious lesion, suspending them in fluid and loading roughly a drop of the mixture into the device. When activated, the device conveys the fluid down a tiny microfluidic channel to a chamber with a porous membrane.
"The cells stick to the membrane floor like starfish in a net," said Shannon Weigum, MS, lead author on the report. "The floor has little exit holes that drain the fluid out of the chamber and allow us to pump in a cocktail of antibodies that are tagged with a fluorescent dye and that are programmed to seek out and attach to the EGFR displayed on the cells," she said.
"The chamber creates a nice, miniaturized platform with a digital camera interface to display the fluorescent tags for analysis on a computer screen," Ms. Weigum explained. "We can then read the level of fluorescence and determine how much EGFR is present on the cell surface. It automates a process that is done now by a pathologist."
The scientists found that their results correlated well with those using flow cytometry, the current gold-standard analytical technique used to quantify protein expression.
The scientists received support from the National Institute of Dental and Craniofacial Research, part of the National Institutes of Health.
