Non-enzymatic glucose sensor; No needles required!

Komal Bavaskar, D Y Patil University

Diabetes mellitus is a quite common disease that might also lead to fatality. Millions of people are affected around the world by this chronic metabolic disorder According to recent research conducted by the World Health Organization (WHO) and the International Diabetes Federation (IDF) – 422 million people are diabetic & the diabetic population is expected to rise to 642 million by 2030. Aside from treatments to reduce blood glucose levels, the development of accurate, dependable, and precise sensors to monitor blood glucose levels is becoming increasingly important in diabetes management.

While looking at such high numbers for blood glucose detection, ~85% of the biosensors are analytical devices. There are two kinds of sensors for measuring glucose levels: enzymatic sensors and non-enzymatic sensors. Due to the instability of enzyme-based biosensors, the development of non-enzymatic sensors is critical. In today’s world, non-enzymatic glucose sensors beat enzymatic ones in terms of cost, durability, sensitivity, stability, and operational length.

Non-enzymatic sensor:

Researchers of Pennsylvania State University have created a novel non-enzymatic sensor utilizing laser-induced graphene (LIG), a material composed of atom-thick carbon layers in different configurations. LIG looked to be a great foundation for the sensing device, with strong electrical conductivity and a simple manufacturing time of only seconds.

Limitation:

The problem here is that LIG is completely insensitive to glucose. As a result, we were required to apply a glucose-sensitive substance to the LIG.

Solution:

Nickel was chosen because of its high glucose sensitivity, and it was coupled with gold to reduce the chance of an allergic response. The researchers expected that the nickel-gold alloy-equipped LIG would be able to detect low quantities of glucose in sweat on the skin’s surface.

A substance with a high glucose tolerance was a primary concern. Sweat has very low glucose concentrations when compared to blood. But there is a significant link between sweat and blood glucose levels. Although the concentration of glucose in sweat is approximately 100 times lower than the concentration in blood. This device will be sufficient to precisely measure the glucose in sweat and reflect the concentration in blood.

Due to the sensitivity of the nickel-gold alloy researchers were allowed to exclude the enzymes, which are generally used to test glucose. These enzymes generally degrade rapidly with time and temperature changes. An enzymatic sensor must be maintained at a specific temperature and pH, and the enzyme cannot be retained indefinitely. A nonenzymatic glucose sensor, on the other hand, benefits from the consistent performance and glucose sensitivity independent of these changes.

How does non-enzymatic sensor work for the body?

Non-enzymatic sensors demand an alkaline solution, which might harm the skin and restrict device wearability. This issue was solved by affixing a microfluidic chamber to the LIG alloy. This chamber is smaller than previously produced designs to increase wearability, and it is porous to allow for a variety of movements, such as stretching or crushing. It is linked to a collecting inlet that allows perspiration (sweats) to enter the solution without enabling the solution to come into contact with the skin. The basic solution combines with the glucose molecules to form a chemical that reacts with the alloy. This process generates an electrical signal that indicates the concentration of glucose in the perspiration. By reducing the size of the alkaline solution chamber, the complete device is about the size of a quarter and flexible enough to retain a secure connection to the human body.

The researchers utilized skin-safe glue to adhere the reusable sensor to a patient’s arm for one hour and three hours after a meal. Just before each measurement period, the patient did a little workout (enough to make him sweat). The researchers discovered that the observed glucose concentration declined from the first measurement to the next a few minutes after obtaining the sweat. The glucose measurements from the sensor were validated using a commercially available glucose monitor.

Penn State University has shared a video in their YouTube channel demonstrating the working of the non-enzymatic sensor.

Link: https://youtu.be/23MpXrneNIM

Future aspects:

Researchers intend to develop their prototype for future applications such as how patients or physicians may utilize the sensor for progressive glucose levels or continuous monitoring to decide therapy measures such as insulin administration. They also plan to improve and expand this platform to allow for more comfortable monitoring of additional biomarkers found in sweat or interstitial fluids, which fill the gap between cells in the body.

They want to collaborate with physicians and other health care professionals to explore how we might use this technology to monitor patients regularly. This glucose sensor serves as a basic example to demonstrate how we might enhance biomarker detection in sweat at extremely low concentrations.

Also read: Genetic basis of the relation between Oxytocin, Adult relationships and Instagram

References:

Zhu, J., Liu, S., Hu, Z., Zhang, X., Yi, N., Tang, K., Dexheimer, M. G., Lian, X., Wang, Q., Yang, J., Gray, J., & Cheng, H. (2021). Laser-induced graphene non-enzymatic glucose sensors for on-body measurements. Biosensors and Bioelectronics, 193, 113606. https://doi.org/10.1016/j.bios.2021.113606

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Author info:

Komal Bavaskar is pursuing M.Sc in Biotechnology. She is a resourceful person with a positive and proactive attitude when faced with diversity. She is interested in the research field and is a very dedicated worker who sets realistic goals. Komal strives to do the best she can for whatever task is presented to her.