A Medical Device Daily

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 (Medical Device Daily, April 18), 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.”

FDA panelist weighs in on DES controversy

The drug-eluting stent (DES) controversy is itself becoming a controversy as indicated by a noted cardiologist who sits on FDA’s circulatory systems advisory committee.

Judah Weinberg, MD, associate professor of medicine at Columbia University Medical Center (New York), said in a recent interview with Medical Device Daily that as a consequence of recent meta-analyses and studies, “patients have been terrified of treatment by stents. They are opting more and more for bypass surgery, and I think that often this is the wrong choice.”

Weinberger added that while “stent safety is an issue, many patients can benefit from treatment with them.”

Weinberger was on the circulatory systems panel during the review of several DES products and said that allegations that there is no difference in mortality between those who opt for DES and those who steered away from them, usually toward bare-metal stents, should not be interpreted as a final ruling on the difference between these two devices.

“On our examination, it transpired that only 25%-30% of the patients treated with stents and included in this research were actually similar to the original trial group for stent approval,” Weinberger said. The cardiologist said that the balance of the patients had chosen stents for off-label use at the advice of their doctors, including instances in which physicians installed more than one stent per blood vessel.

Weinberger also said that it isn’t clear “what the cause of death was in those patients treated with [drug-eluting] stents, which led to their numbers being equal to those not treated with stents and who died from heart problems.” He said that examinations of patients DES-implanted according to labeled indications made it clear that when “treatment with stents was according to instructions ... the stent had a positive effect. It reduced the scarring and re-clogging of the artery, without significantly increasing the side effects.”

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