Microneedle Array Technology in CGM

Introduction to Microneedle Array Technology in Continuous [Glucose Monitoring](/)

A microneedle (MN) array is a patch of tiny projections, most shorter than 1.5 mm, that reaches into the dermis, the skin layer just under the surface, instead of the fat beneath it [9]. The sensors from Dexcom and Abbott that most people picture don't use microneedles at all [8]. As of October 2026, one microneedle CGM has FDA authorization: the Biolinq Shine, whose seven microelectrodes sit in the upper (papillary) dermis of the inner forearm [2]. The main appeal is comfort. Microneedles usually stop short of the nerves and blood vessels deeper in the dermis, which is why researchers describe them as painless [9], although we found no pain claim in the FDA's decision summary for Shine [2]. Developers also hope dermal sensing will shorten lag time, the delay between a change in blood glucose and the same change in the fluid the sensor reads. The evidence on that point is still thin, as we explain below.

Technical Principles of Microneedle Array Technology

Each microneedle works like a miniature version of the electrode inside a standard CGM. In Shine, the enzyme glucose oxidase reacts with glucose in interstitial fluid (ISF), the fluid that bathes the cells, and produces an electric current proportional to the glucose present [2]. An adhesive patch holds the device on the forearm. It begins reporting about two hours after application and doesn't need fingerstick calibration [2].

The two companies most often named in this field have very different regulatory records. The FDA granted Biolinq's De Novo request for Shine, as a prescription device, on September 23, 2025 [3], and cleared it for over-the-counter use on September 18, 2026 [4]. Both cover adults 22 and older who don't use insulin. Instead of numbers, Shine shows glucose ranges with colored lights, and its labeling says users shouldn't take medical action on its output without consulting a healthcare professional [2][4]. We couldn't confirm from a primary source when the over-the-counter version goes on sale.

PKvitality, a French company, developed the K'Watch, a watch with a replaceable microneedle sensor that reads ISF glucose through a glucose oxidase reaction [7]. Here's what surprised us: a 2021 review already listed the K'Watch as neither FDA-cleared nor CE-marked [7], and when we searched FDA's databases in October 2026, we still found no 510(k) or premarket approval records for PKvitality [5][6]. The FDA has also said it hasn't authorized any smartwatch or smart ring intended to measure blood glucose on its own [10].

Key Benefits and Advantages

The case for microneedle arrays rests on a few ideas, and the evidence behind each one differs:

• Multiplexing: Because an array has many separate sensing sites, each can carry a different enzyme. Research prototypes have paired glucose with lactate and alcohol on a single microneedle patch, and ketone-sensing microneedle patches have also been reported [8]. Biolinq describes its platform as built for sensing multiple analytes [1], but Shine's FDA authorizations cover glucose only [2][4].
• Usability: Biolinq says its sensors are "so small you can barely feel them" [1]. That is the manufacturer's description, not a study result. Shine still goes on with a single-use applicator [2]. The FDA summary doesn't describe how that applicator works, so we can't confirm the common claim that microneedle CGMs do away with spring-loaded inserters.
• Lag Time: One dermal prototype showed a physiological lag of about 10 minutes, consistent with how quickly glucose diffuses [8]. We found no head-to-head study showing that dermal sensors lag less than subcutaneous CGMs. Physiological lag also varies between people and depends on how fast blood glucose is changing [7].

Challenges and Limitations

Getting a sensor into the dermis reliably, and keeping it working once it's there, is harder than it sounds:

• Mechanical Insertion: Skin is elastic, and a dense array can press the surface down instead of piercing it evenly, which is often described as the "bed of nails" effect. Even insertion matters because every needle needs consistent electrical contact with the tissue. Reviews also note that hollow microneedles can bend or insert unevenly, and silicon microneedles can break off under the skin [9].
• Sensor Stability: The enzyme layer has to survive being pushed through the skin. One research team built cavities into its array specifically to protect that layer during insertion, calling it critical to sensor performance [8]. Biofouling, the buildup of proteins and cells on a sensor's surface, is another problem: researchers say microneedle tips need better protection against it to reach the 15 days or more of common CGM platforms [8]. Shine is labeled for up to five days of wear [2]. Developers also have to work with the lower volume of ISF available in the dermis compared to subcutaneous tissue.

Conclusion

As of October 2026, microneedle CGMs have moved from lab prototypes to one FDA-authorized product, and that product is narrow. Shine measures glucose only and shows color-coded ranges rather than numbers. It is meant for adults who don't use insulin [2][4]. Multi-analyte sensing and shorter lag remain research findings, not features of an authorized device [8]. Whether a sensor like this fits into someone's diabetes management is a decision for their care team.