A Diagnostics & Imaging Week

If the prospect of a trip to the dentist leaves you with a chip on your shoulder, you’re not alone. In times to come, though, your dentist might have a chip for you.

However, this chip will contain a Lilliputian lab instead of a bad attitude about oral health.

The National Institute of Dental and Craniofacial Research, part of the National Institutes of Health, reported recently that its funding is yielding results in the form of another lab-on-a-chip — this one developed at the University of Texas at Austin (UT; Austin, Texas) — that will tell you before you leave the dentist’s office whether that sore in your mouth is a harbinger of cancer or not.

An NIDCR grant has allowed a group of researchers at UT to develop a technology that can detect the presence of epidermal growth factor receptors (EGFRs) on the surface of cells that line the mouth, a useful approach since EGFRs are much more common on cancerous cells than on healthy cells. The diagnostic operates by taking a sample of saliva through a microfluidic channel into a compartment with a porous membrane, where cells adhere as the more watery elements of saliva drain away through tiny holes.

Micro-sized diagnostics using human saliva to detect oral cancer are the subject of considerable interest, and micro-sized assays of all types are now hot enough to justify publication of a new medical journal dedicated to this field titled Lab on a Chip.

According to the NIH press release, Shannon Weigum, PhD, the paper’s lead author and a member of the team at the UT lab, said the cells “stick to the membrane floor like starfish in a net.” Weigum said the next step entails filling the compartment with dyed antibodies that are shaped precisely so as to dock with the EGFRs.

She said that the compartment “creates a nice, miniaturized platform with a digital camera interface to display the fluorescent tags for analysis on a computer screen.” The display allows the viewer to “read the level of fluorescence and determine how much EGFR is present on the cell surface.”

And all this comes in a package about half the size of a toaster.

The most important element of this diagnostic, other than its size, may be speed. John McDevitt, PhD, the lead researcher at the McDevitt Research Lab at UT, where Weigum works, said in the NIH statement that “the speed and efficiency that this test will bring to the diagnostic process” is the best part, turning diagnoses around in as little as 10 minutes. He said that as a consequence of this kind of development, patients will no longer “need to endure referrals, long waits for test results, and scheduling follow up consultations. Patients will get immediate results and feedback from their dentist or doctor on how best to proceed.”

As matters stand, patients usually have to submit a tissue sample scraped painfully from the inside of the mouth, and most conventional labs will rarely turn around the results in less than three days. Many patients get to spend a week stewing over the prospect of oral cancer before the biopsy comes back. As the article in Lab on a Chip points out, oral cancer is “the sixth most common cancer worldwide and has been marked by high morbidity and poor survival rates that have changed little over the past few decades.”

As if we need another reason to steer clear of the dentist.

According to the NIH statement, McDevitt said that the team in his lab is following this proof-of-principle study for EGFR with an attempt to tweak the device to pick up other proteins and genes that indicate cancer, and the path from lab to clinic might be fairly quickly traversed.

“It could take several months to more than a year before we make the transition,” McDevitt said, adding that “the diagnostic platform has been built, and it’s just a matter of fine tuning the components that already are in place.”