Skin-Deep Monitoring: The Role of Microneedle Glucose Sensors in Continuous Health Tracking

Biolinq Takes Inspiration from Semiconductor Manufacturing

For individuals managing diabetes, glucose monitors are essential in tracking blood sugar levels. Typically, these devices function by inserting thin metallic filaments into the subcutaneous tissue, the deepest skin layer containing most body fat. However, the medical technology firm Biolinq is pioneering a different glucose sensor model that operates within the dermis, the middle skin layer, just above the subcutaneous tissue.

The company’s innovative “intradermal” biosensors leverage the metabolic activity in the upper skin layers, utilizing a network of electrochemical microsensors capable of measuring glucose and other body chemicals right beneath the surface of the skin. Biolinq recently wrapped up a significant clinical trial, as noted by CEO Rich Yang, and aims to submit the device for U.S. Food and Drug Administration approval by year-end. Earlier this year, Biolinq garnered US million in funding to finalize these clinical trials and move forward with FDA submission.

Yang describes Biolinq’s sensor as “the world’s first intradermal sensor that is fully autonomous.” Unlike standard glucose monitors that require smartphones or separate devices to display data, Biolinq’s design features an LED display that indicates whether glucose levels are healthy (blue light) or exceeding the normal range (yellow light). This setup provides instant feedback for users who might not notice symptoms immediately. Additionally, users can upload long-term data onto a smartphone merely by placing it near the sensor, similar to Abbott’s FreeStyle Libre glucose monitor.

Biolinq places the device on the upper forearm for easy visibility, allowing users to receive instantaneous readings. For example, if someone consumes sugary beverages, they can observe their glucose level shift from blue to yellow, enhancing awareness of their glucose responses. The device is built using an array of microneedles on a silicon wafer, crafted through semiconductor manufacturing techniques, which differs from conventional methods that utilize introducer needles.

Each chip is compact, measuring 2mm by 2mm, housing seven independent microneedles, with membranes applied via a process similar to electroplating. Biolinq tackled a significant challenge in avoiding sensor breakage at this small scale. Yang emphasized that silicon is tougher than both titanium and steel at the required dimensions. This miniaturization process allows monitoring closer to the skin, optimizing the uptake of metabolic activity and making it an ideal location for glucose tracking, as well as monitoring other biomarkers.

With an integrated sensor array, Biolinq’s device will also be able to detect lactate, a marker of muscle fatigue, and ketones, substances produced when burning fat. This could essentially provide a metabolic profile from a single chip. Having multiple sensors enhances reliability, enabling better management of accuracy drift over time.

The autonomous display does, however, impact battery life, currently restricting the biosensor’s wear time to 5 days. The second generation of the device is slated to extend wear time to 10 days by incorporating a custom low-power chip.

Biolinq has amassed nearly 1 million human performance hours of data alongside benchmarks from commercial glucose monitors and blood samples. The current goal is to secure FDA approval for use among non-insulin-dependent type 2 diabetes patients before exploring additional medical applications.

This article will be featured in the August 2024 print edition as “Glucose Monitor Takes Page From Chipmaking.”