Brazilian and US scientists have developed a glasses-based biosensor capable of measuring blood glucose levels through a person’s tears, offering a less invasive test for diabetics.
Glucose levels need to be frequently monitored in people with diabetes, a disease that affects 62 million people in the Americas and 380 million worldwide.
According to the World Health Organization (WHO), diabetes has been rising alarmingly in recent decades — with the fastest increase in low- and middle-income countries — and could affect 580 million people by 2035.
Many people with the disease use a portable glycosometer to measure blood glucose levels by pricking their fingertips to get a blood sample. The process, which may be repeated several times a day, can be painful and carries a risk of infection.
The Brazilian biosensor can identify an enzyme called glucose oxidase — widely used to detect free glucose in body fluids — in tears, eliminating the need for finger pricking. It can also measure blood sugar, vitamin and alcohol levels.
Biosensors are able to measure biological or chemical reactions and generate 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, and diagnose and prevent disease, even in some developing countries such as Brazil.
As the tears come into contact with the glucose oxidase, it alters the flow of electrons, producing a signal that is recorded and processed by the device installed in the arm of the eyeglasses, which sends the results in real-time to a computer or smartphone.