Brazilian and U.S. scientists have developed prescription glasses equipped with a biosensor that can measure blood glucose levels through a person's tears. They can lead to less invasive testing for diabetics.
Glucose levels need to be checked frequently to monitor diabetes. It is a disease that now affects 380 million worldwide. Today, biosensors can solve the problem.
According to the World Health Organization (WHO)diabetes has risen alarmingly in recent decades. The biggest increase is in low and middle income countries, and could affect 580 million people by 2035.
Many people use a portable glucose meter to monitor diabetes by observing blood glucose levels. They prick their fingers, obtain a blood sample and submit it to a device for analysis. The process, which can be repeated several times a day, can be painful and carries a risk of infection. The new (different and encouraging) methods have not yet taken off.
The biosensors developed by the USA-Brazil team are able to identify an enzyme called glucose oxidase (widely used to detect free glucose in body fluids) from tears, eliminating the need to prick your fingers. But that's not all: they can also measure blood sugar, vitamin and alcohol levels.
Biosensors are capable of measuring biological or chemical reactions and generating a signal proportional to the concentration of a particular substance. They are increasingly being designed and used to speed up laboratory test results, monitor health conditions, diagnose and prevent disease.
Monitor diabetes through tears
The project was born from researchers from São Carlos Physics Institute of the University of São Paulo, together with scientists from the Department of Nanoengineering from the University of California, San Diego. The teams immobilized the enzyme on an electrode coupled to a circuit with a constant flow of electrons, then installed the device on the nose pad of the glasses. The user can produce tears on command (if he has good acting skills…just kidding) or by exposing his eyes to a substance that stimulates the lacrimal gland.
When the tears come in contact with glucose oxidase, they alter the flow of electrons, producing a signal that is recorded and processed by the device installed in the bar of the glasses, which sends the results in real time to a computer or smartphone.
Laís Canniatti Brazaca, doctor and researcher at the Institute of Chemistry of São Carlos and one of the authors of the study published in the journal Biosensors and Bioelectronics, He declares: “Concentrations of various metabolites in tears reflect concomitant blood levels, making them fertile ground for biosensors that can monitor diabetes noninvasively, and also observe other physiological parameters.”
In addition to being painless, the biosensor could "reduce the risk of infection in people who frequently use glycosometers," Brazaca added.
The scientist said the device could also measure the levels of vitamins and alcohol in the blood “simply changing the electrode positioned on the nose pads of the glasses”.
A single drop of blood
Using the same approach, a team of researchers from Sao Paulo State University has developed biosensors capable of detecting and quantifying biomarker proteins for the clinical diagnosis of neglected diseases and chronic degenerative diseases, such as certain types of cancer.
Paulo Roberto Bueno, materials engineer at the Chemical Institute of São Paulo State University, “the idea is to conduct the test using just a drop of blood on the device.”. A bit like the dream (unfortunately it turned out to be such) of Elizabeth Holmes and her Theranos.
This simple approach could improve disease diagnosis by medical professionals or patients themselves at home. With the help of artificial intelligence software they could monitor vital parameters.
The researchers plan to market the new device within three years. In the case of biosensors mounted on glasses to monitor diabetes, the device is not yet expected to reach the market.
Biosensors: it takes time, unless…
Cleverton Pirich, a biochemist at Paraná Federal University, Brazil, said the benefits of biosensors for improving the quality of life and human health have long been known. However, there is still a way to go to produce and market them on a large scale, at least in countries like Brazil.
