The reality that people with diabetes must face is that they have to test their blood glucose regularly, and thankfully it’s getting easier to do so. And blood glucose meters are more sensitive, require less blood sampling, and are less painful. But will the “pain” go away forever?
Researchers are working to make blood glucose levels “pain-free” by developing special contact lenses, fluorescent “tattoos”, infrared devices, and smart sensors to monitor blood glucose levels. In some cases, no blood tests are needed, and perhaps a single pinprick is enough.
Dr. Guenther Boden, director of endocrinology at Temple University School of Medicine, has been following developments in this field for the past few decades.
Guenther describes, “A watch-based ambulatory glucose monitoring system seems to be the answer. The watch has a membrane at the bottom that absorbs interstitial fluid through the skin, that is, it gets this ‘interstitial fluid’ from the skin, which is what is needed to measure glucose. This technology works immediately, but it can be irritating to the skin.”
Audrey Finkelstein, a spokeswoman for a product manufacturing company (Animas Corporation), said, “We are currently working on a third-generation monitoring system, which would be a combination of a monitoring system and microneedles that would provide a better blood sample than other technologies and would also greatly reduce or even eliminate irritation to the skin.”
Improvements in technology
The advantage of watch-based glucose meter products is that they alert patients to possible dangers at any time, which is especially important during sleep time.
Another device that tracks trends in blood sugar, the continuous glucose monitor, is the body’s “guardian” and was approved by the U.S. Food and Drug Administration (FDA) in February 2004. The device is not easy to operate, Guenther said. It provides data that can be downloaded by doctors to monitor blood sugar trends over a 72-hour period, but patients don’t get an immediate reading of their blood sugar values. Also, the values measured at night are not accurate enough. Guenther noted, “The manufacturing company is working to address this issue.”
Deanne Mc Laughlin, who works in the diabetes department at Manufacturing, said an improved version of the device is in clinical trials in Europe. Deanne describes, “Continuous glucose monitoring allows patients to better understand the impact of treatment, diet and activity levels on blood glucose levels.” Regarding the improved device, he said, “We are very pleased with the ‘real-time’ readings and the potential the device has shown as far as helping patients control their blood glucose.”
Besides that, Guenther noted, “We’re still stuck in the finger prick phase. There is a wide variety of glucose meters and they have been upgraded. The biggest advancement is that the newer instruments require less blood collection. This means that there is no need to prick the finger and the option to test in a less painful area, such as the base of the arm. The pain in the arm is relatively mild, whereas the pain in the fingertip is very pronounced, which is the biggest difference.”
As for new devices in the development stage, the jury is still out. Here are a few issues that need to be brought to our attention.
Getting answers from the eyes
Like the mood bracelets of the 1970s, contact lenses could one day show blood glucose levels directly. All you have to do is look in the mirror to know if something is wrong with your blood sugar.
Sanford Asher, PhD, a professor of chemistry at the University of Pittsburgh Medical Center, led this innovative project, which took 20 years to develop. We’re making fast progress so far,” Sanford said. Given the existing experience with soft contact lenses, we’re not sure how extensive a clinical trial we need to conduct.”
Here’s how it works: A thin plastic sensor is embedded in a traditional soft contact lens, which Sanford explained patients need to change once a week. The sensor detects the amount of glucose in the tears, and the color of the contact lens changes in response to the sugar content. The sensor is placed in the lower part of the iris below the eye’s pupil in tiny crescent-shaped colors, green (normal), blue (too low blood sugar) or purple (severely low blood sugar). Other colors reflect high blood glucose levels, or hyperglycemia.
Sanford’s group conducted “the exact study that confirmed that tears can provide an accurate measure of the body’s glucose levels,” he said. His group overcame difficulties to develop their own innovative method to obtain enough normal state tears for their study.
It may be possible to develop a handheld tester or special mirror to help patients get accurate blood glucose levels. There’s no need for finger punctures anymore,” Sanford said. In fact, it’s more accurate than a finger prick because that monitoring is continuous. The color is constantly changing so you know if you’re in hypoglycemia or hyperglycemia.”
Tattoos that glow in the dark
The tattoo inspired another novel device. It was based on the idea that in addition to implanting ink particles under the skin, then why not implant small beads that change color in response to changes in blood sugar levels in the body?
Gerard Cote, a professor of biomedical engineering, explained that engineers and chemists at Texas A&M University have developed fluorescent colored beads that emit different colors of light as blood sugar levels change.
The beads are wrapped in a very thin, hair-sheath-like substance, which buries them under the skin. When the LED light (on the watch) shines on the corresponding area of the skin, the beads glow, and their color indicates the glucose level. the LED monitor also records the exact glucose level. If the glucose is too low, an alert is sent.
Kids like the concept, he said. That’s because it clearly shows some of the “cool factors. He said, “It’s embarrassing for kids to have their blood sugar checked when the little ones are around. But now I have kids saying to me, ‘Come and get my tattoo! Note that the butterfly or heart “tattoos” are not the “real tattoos” you normally see.
For those who may have problems with their blood sugar at night, the luminous monitor will help to get a quick reading in the dark. Often times, partners wake patients up because they are sweating and need to take sugar pills to raise their blood sugar levels,” he explained. With this LED monitor, monitoring can be done at any hour of the night.” With this implant, there is no need to do any finger punctures.
Emits infrared light
The infrared light shines through blood sugar levels. Developers are testing devices that emit near-infrared light and shine it on the skin. Some of the infrared light is absorbed by the fat and proteins in the body’s tissues. And the information contained in the light that is not absorbed is reflected back to the receiver, and the blood glucose level is known using the reflection.
Stephen Monfre, MD, with Medical Corporation of Chandler, AZ, has developed such a device, which has been refined through several clinical trials. Stephen described the infrared device as the size of a “portable laptop”. To use it, a “sensor head” is placed on the forearm, which emits infrared light to the laptop for analysis and reporting of blood glucose levels.
Stephen said the device currently requires daily finger punctures for calibration. “We think it can be eliminated in the long run, but it requires more research, more money, and raising money is difficult.”
The story of the sensor
There is also huge interest in sensors, which can provide continuous glucose monitoring for 24 hours. Several companies are currently competing to produce the best sensors. Each body wears a sensor (similar to a patch) that “reads” the glucose levels in the body. The sensor then sends the information to the patient’s receiver. In most cases, the sensor alerts the patient when glucose levels are too low or too high.
These patches are not quite like the peel-and-stick smoking cessation patches. To use the patch you have to get the skin ready first, and usually, the sensor has to be implanted in the subcutaneous tissue. To calibrate these new monitors, a finger prick glucose test is still required, about 2 times a day.
There is also a device that uses ultrasound for continuous monitoring. Each morning, a patch is adhered to a small area of skin that has been prepared for the skin penetration device. The patch transmits ultrasound to body fluids to monitor glucose. Sean Moran, the company’s chief financial officer, reports, “It’s more accurate because of the skin permeability level, and you get a reading every second.” A daily finger puncture is necessary to calibrate the device.