Written by Emily Majorkiewicz
Nearly 100 years after the discovery of insulin, a new device for monitoring blood-glucose levels may soon be available, and it involves your eyeballs!
Since the 1980s, the number of adults around the world living with diabetes has quadrupled to over 420 million [3]. Living with this increasingly prevalent condition involves daily careful and constant monitoring of blood glucose levels. Uncontrolled blood glucose levels can lead to a variety of health detriments, including kidney failure, stroke, and heart disease.
The prick of a needle is an all too familiar sensation for diabetes patients, as blood tests have continued to be the standard method for checking blood glucose levels. A new device that involves contact lenses may someday replace such tests altogether.
Unlike standard contact lenses, these devices incorporate a tiny sensor into the lens material that is capable of monitoring blood glucose levels from the eye’s tears. In addition to preventing dryness, transporting oxygen, and preventing infection, tears also function as a buffer, providing a stable pH environment for the eye and its tissues [1].
Using this information, a research group at Oregon State University has been working on a sensor that uses a nanostructured transistor to analyze even slight changes in glucose levels [4]. For maintaining the condition, the sensors within the lenses would also be able to continuously send information about blood sugar levels to a pump. This pump would be able to administer the correct hormone to regulate the blood glucose levels, eliminating the need for puncturing the skin. Similarly, researchers at the University of Houston have been working on a device that involves glucose in optical sensing for Raman scattering spectroscopy, another non-invasive device that uses sensing techniques developed by one of the university’s associate professors [5]. In this sensor, a gold film and stacked layers of gold nanowires are used in conjunction with the scattering spectroscopy to detect small samples of glucose within the eye fluid [6].
Contact lenses can have applications beyond just glucose sensing, as the convenient position of the sensor is what allows for the versatility of the device. Google has presented a patent for contact lenses that can function as sensors for a variety of physiological conditions [2]. Blood-oxygen levels, pulse rate, and even cancer detection are among the many potential uses that this developing device offers.
For individuals living with diabetes, constant monitoring of glucose levels can become a hindering task. Although still in development, these contact lenses, which swap external application in place of invasive blood tests, have the potential to make the routine easier.
References:
1. Carney, L.G., Mauger, T.F., Hill, R.M. Buffering in Human Tears: pH Responses to Acid and Base Challenge (1989) Invest Ophthalmol Vis Sci. (30)4:747-754.
2. Duffy, Maureen. “Google’s Prototype ‘Smart Contact Lens’: Measuring Blood Glucose Levels for People with Diabetes.” American Foundation for the Blind. 31 July 2014. Web. 9 Jan. 2017.
3. “Global Report on Diabetes.” World Health Organization. World Health Organization, 2017. Web. 9 Jan. 2017.
4. “Glucose-monitoring Contact Lens Would Feature Transparent Sensor.” News and Research Communications | Oregon State University. Oregon State University, 1 Nov. 2016. Web. 10 Jan. 2017.
5. University of Houston. “Glucose-sensing contact lens invented.” ScienceDaily. ScienceDaily, 3 October 2016.
6. Yindong Qu, Henry Medina, Sheng-Wen Wang, Yi-Chung Wang, Chia-Wei Chen, Teng-Yu Su, Arumugam Manikandan, Kuangye Wang, Yu-Chuan Shih, Je-Wei Chang, Hao-Chung Kuo, Chi-Yung Lee, Shih-Yuan Lu, Guozhen Shen, Zhiming M. Wang, Yu-Lun Chueh. 2016. Wafer Scale Phase-Engineered 1T- and 2H-MoSe2/Mo Core-Shell 3D-Hierarchical Nanostructures toward Efficient Electrocatalytic Hydrogen Evolution Reaction. Advanced Materials. 28(44):9831-9838.