You and your dentist have a lot of tools and techniques for stopping cavities, but detecting the specific chemical conditions that can lead to cavities and then preventing them from ever getting started is much harder. Now, in a new , 91探花 researchers have shown that a dental tool they created can measure the acidity built up by the bacteria in plaque that leads to cavities.

The O-pH system is a prototype optical device that emits an LED light and measures the reactions of that light, the fluorescence, with an FDA-approved chemical dye applied to teeth. The O-pH then produces a numerical reading of the pH, or acidity, of the plaque covering those teeth. Knowing how acidic the plaque is can tell dentists and patients what area of a tooth is most at risk of developing a cavity.

鈥淧laque has a lot of bacteria that produce acid when they interact with the sugar in our food,鈥� said , lead author and a doctoral student in the 91探花Department of Electrical & Computer Engineering. 鈥淭his acid is what causes the corrosion of the tooth surface and eventually cavities. So, if we can capture information about the acidic activity, we can get an idea of how bacteria are growing in the dental biofilm, or plaque.鈥�

Sharma explained that not all bacteria in that biofilm are bad or will lead to cavities, so measuring the acidity of the environment can tell a dentist what they need to know about the threat of developing problems. That can limit the need to test for specific harmful bacteria, of which there can be a multitude.

To test their device, the researchers recruited 30 patients between the ages of 10 and 18, with a median age of 15, in the 91探花School of Dentistry鈥檚 . The researchers chose kids for their study in large part because the enamel on kids鈥� teeth is much thinner than that of adults, so getting early warning of acid erosion is even more important. To perform the measurements with the O-pH device, the researchers also recruited second- and third-year students in the dentistry school, who were supervised by a faculty member.

The test is non-invasive. While the dye is applied to the teeth, at the end of a length of cord is the probe that transmits and collects light while hovering over the surface of a tooth (see photos). The collected light travels back to a central box that provides a pH reading. The conditions on the patients鈥� teeth were read several times before and after sugar rinses and other condition changes, such as pre- and post-professional dental cleaning.

, senior author and research professor of mechanical engineering in the 91探花College of Engineering, said the idea for adding the acidity test as a new clinical procedure came from envisioning that when a patient first sits in the dental chair, before their teeth get cleaned, 鈥渁 dentist would rinse them with the tasteless fluorescent dye solution and then get their teeth optically scanned to look for high acid production areas where the enamel is getting demineralized.鈥�

The was published in February in IEEE Transactions on Biomedical Engineering. The research team reported that one limitation to their study was being unable to consistently measure the same location on each tooth during each phase of testing. To address this limitation, in particular, the researchers are evolving their device to a version that produces images for dentists that instantly show the exact location of high acidity, where the next cavity may occur.

鈥淲e do need more results to show how effective it is for diagnosis, but it can definitely help us understand some of your oral health quantitatively,鈥� said Sharma. 鈥淚t can also help educate patients about the effects of sugar on the chemistry of plaque. We can show them, live, what happens, and that is an experience they鈥檒l remember and say, OK, fine, I need to cut down on sugar!鈥�

Co-authors include Lauren Lee, 91探花Department of Microbiology; Matthew Carson, 91探花Human Photonics Laboratory; David Park, Se An, Micah Bovenkamp, Jess Cayetano, Ian Berude, Zheng Xu, Alireza Sadr, 91探花School of Dentistry; and Shwetak Patel, 91探花Electrical & Computer Engineering and the Paul G. Allen School of Computer Science & Engineering. This research was funded by the National Science Foundation, Oral Health Monitor, Institute of Translational Health Sciences; and the National Center for Advancing Translational Sciences of the National Institutes of Health.

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For more information, contact Seibel at eseibel@uw.edu.

A from 91探花and University of Michigan researchers in Nature Biomedical Engineering reports proof-of-concept results for this new imaging platform for atherosclerosis.

鈥淭he camera actually goes inside the vessels,鈥� says first author , a Michigan Medicine resident neurosurgeon. 鈥淲e can see with very high resolution the surface of the vessels and any lesions, such as a ruptured plaque, that could cause a stroke. This technology could possibly find the 鈥榮moking gun鈥� lesion in patients with strokes of unknown cause, and may even be able to show which silent, but at-risk, plaques may cause a cardiovascular event in the future.鈥�

The scanning fiber endoscope, or SFE, used in the study was invented and developed by co-author and 91探花mechanical engineering research professor He originally to clearly image cancer cells that are currently invisible with clinical endoscopes.

The Michigan Medicine team used the instrument for a new application: acquiring high-quality images of possible stroke-causing regions of the carotid artery that may not be detected with conventional radiological techniques.

Researchers generated images of human arteries using the SFE, which illuminates tissues with multiple laser beams and digitally reconstructs high-definition images to determine the severity of atherosclerosis and other qualities of the vessel wall.

鈥淚n addition to discovering the cause of the stroke, the endoscope can also assist neurosurgeons with therapeutic interventions by guiding stent placement, releasing drugs and biomaterials and helping with surgeries,鈥� Seibel says.

In addition, the SFE uses fluorescence indicators to show key biological features associated with increased risk of stroke and heart attacks in the future.

鈥淭he ability to identify and monitor the biological markers that render a plaque unstable and at risk for rupture could enable the detection of individuals within high-risk populations who are most likely to suffer from cardiovascular events, and therefore benefit the most from preventive treatment during the asymptomatic stage,鈥� says professor of neurosurgery at the University of Michigan Medical School and a senior author on the new paper.

鈥淚n addition, plaque-specific data could help physicians modulate treatment intensity of atherosclerosis, which is currently based on systemic surrogates such us cholesterol and blood sugar levels and occurrence of cardiovascular events such as stroke or myocardial infarction鈥�

All research is in the pre-clinical phase.

The research was funded by the American Association of Neurological Surgeons and Congress of Neurological Surgeons, and National Institutes of Health.

Co-authors include 91探花mechanical engineering doctoral student and University of Michigan鈥檚 Quan Zhou, Arlene Smith, Carlos Murga-Zamalloa, David Gordon, Jon McHugh, Lili Zhao, Michael M. Wang, Aditya Pandey, Jie Xu, Jifeng Zhang, Y. Eugene Chen and Thomas D. Wang.

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For more information, contact Seibel at eseibel@uw.edu or University of Michigan authors through Haley Otman at 734 764-2220.

This release was adapted from a University of Michigan .

Routine screenings for breast, colon and lung cancers have improved treatment and outcomes for patients with these diseases, largely because the cancer can be detected early. But because little is known about how pancreatic cancer behaves, patients often receive a diagnosis when it’s already too late.

91探花 scientists and engineers are developing a low-cost device that could help pathologists diagnose pancreatic cancer earlier and faster. The prototype can perform the basic steps for processing a biopsy, relying on fluid transport instead of human hands to process the tissue. The team presented its initial results this month (February 2014) at the and recently filed a patent for this first-generation device and future technology advancements.

“This new process is expected to help the pathologist make a more rapid diagnosis and be able to determine more accurately how invasive the cancer has become, leading to improved prognosis,” said , a 91探花research professor of mechanical engineering and director of the department’s .

The new instrumentation would essentially automate and streamline the manual, time-consuming process a pathology lab goes through to diagnose cancer. Currently, a pathologist takes a biopsy tissue sample, then sends it to the lab where it’s cut into thin slices, stained and put on slides, then analyzed optically in 2-D for abnormalities.

The UW’s technology would process and analyze whole tissue biopsies for 3-D imaging, which offers a more complete picture of the cellular makeup of a tumor, said , a 91探花postdoctoral researcher in bioengineering who is the lead author on a related paper.

“As soon as you cut a piece of tissue, you lose information about it. If you can keep the original tissue biopsy intact, you can see the whole story of abnormal cell growth. You can also see connections, cell morphology and structure as it looks in the body,” Das said.

In this video, tissue biopsies first are seen moving through the transparent channels of a microfluidic device. In the second cut, an optical clearing fluid illuminates the original channels. Moving whole tissue samples through such a device is unprecedented.

The research team is building a thick, credit card-sized, flexible device out of silicon that allows a piece of tissue to pass through tiny channels and undergo a series of steps that replicate what happens on a much larger scale in a pathology lab. The device harnesses the properties of microfluidics, which allows tissue to move and stop with ease through small channels without needing to apply a lot of external force. It also keeps clinicians from having to handle the tissue; instead, a tissue biopsy taken with a syringe needle could be deposited directly into the device to begin processing.

In this video, a piece of tissue first is deposited into the microfluidic device by a needle that is used clinically by pathologists to take biopsy samples from patients. The tissue then is propelled down a channel, where both a stain and a wash process the tissue, simulating steps in a pathology lab. Finally, the tissue is moved along the channel and out of the device.

Researchers say this is the first time material larger than a single-celled organism has successfully moved in a microfluidic device. This could have implications across the sciences in automating analyses that usually are done by humans.

Das and , a 91探花undergraduate student in mechanical engineering, designed the device to be simple to manufacture and use. They first built a mold using a petri dish and Teflon tubes, then poured a viscous, silicon material into the mold. The result is a small, transparent instrument with seamless channels that are both curved and straight.

The researchers have used the instrument to process a tissue biopsy one step at a time, following the same steps as a pathology lab would. Next, they hope to combine all of the steps into a more robust device 鈥� including 3-D imaging 鈥� then build and optimize it for use in a lab. Future iterations of the device could include layers of channels that would allow more analyses on a piece of tissue without adding more bulk to the device.

For Burfeind, who started working in Seibel’s lab his sophomore year, the research apprenticeship has been beneficial both for his college experience and future career, and for the lab.

“I’m getting theory from my professors in class, then applying it to my research here,” Burfeind said. “I see this research as a way to enhance cancer diagnosis and catch it earlier so patients can have a better chance of survival.”

The 91探花researchers say the technology could be used overseas as an over-the-counter kit that would process biopsies, then send that information to pathologists who could look for signs of cancer from remote locations. Additionally, it could potentially reduce the time it takes to diagnose cancer to a matter of minutes, Das said.

The team is working with , a pathologist with 91探花Medicine. The research is funded by the National Science Foundation Bioengineering division and the U.S. Department of Education Graduate Assistance in Areas of National Need program.

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For more information, contact Seibel at eseibel@uw.edu or 206-616-1486, and Das at rdas@uw.edu or 206-221-3813.

Grant numbers: NSF Bioengineering division (CBET-1212540).