Rise of the Smart Patch: The Next Generation of Biomarker Sensing

From Skin to Signal: smart patches stream real-time biomarkers like cortisol, lactate, and troponin

Smartwatches and rings have taken us far. They count, pulse, nudge, and coach. But they mostly infer what’s happening inside the body. The next wave measures it directly. Smart patches—thin, skin-worn sensors—continuously watch the chemistry of our interstitial fluid or sweat to show how our metabolism is changing in real time. Continuous glucose monitors opened the door; a broader class of patches is now stepping through it.

Across the last year of WT and eWear showcases, the pattern is clear: quieter, faster progress. Microneedles are more comfortable, micro-cannulas for ISF access have moved beyond “novelty,” and sensing chemistries are more versatile. The user experience is simpler, too: patches talk via Bluetooth to a phone, while edge or cloud AI turns streams of signals into plain-English trends. With fresh regulatory momentum in glucose monitoring and a crowded pipeline of non-glucose targets, this isn’t just lab talk anymore—it’s something people will be wearing at home in the near future.

What counts as a “smart patch”

Smart patches are a sensors that adhere to the skin and continuously tracks molecules, not just heart rate or motion. Most do this by gently sampling interstitial fluid (ISF) using microneedles or cannulas you barely feel, or by steering sweat through soft channels across tiny sensors. The output isn’t a single number; it’s a trajectory—how quickly a marker is rising or falling, whether it’s drifting out of range, and how that aligns with symptoms, sleep, activity, or reference levels that indicate the severity of an ongoing condition or an imminent flare.

That’s why continuous has the potential to provide more nuanced information and earlier warnings than point-of-care measurements.

What these patches aim to measure

Glucose remains the flagship, but it’s no longer the whole story. On the metabolic side, lactate and ketones are edging toward everyday relevance for athletes and for patients in rehab or cardiac care. Cortisol brings a lens on stress. Electrolytes like sodium and potassium matter for hydration and for heart-failure patients who live on a tightrope. Creatinine offers a pragmatic read on cardio-renal status in congestive heart failure, and troponins—while technically challenging in ISF—are so central to cardiac detection that they belong in the conversation. On the inflammation front, cytokines and CRP are emerging, while drug levels (therapeutic drug monitoring) are a natural fit for medications with narrow safety windows.

Not every analyte is equally tractable. Larger proteins can be scarce in ISF and slower to move from blood to skin, which makes some cardiac markers (like troponin) harder to read continuously at the surface. But the overall menu is expanding, and so are the use-cases.

How a smart patch works

A typical patch completes a simple loop. The device samples interstitial fluid just beneath the skin—via microneedles or micro-cannulas—or guides sweat across a channel so molecules can meet a small sensing surface. That surface is coated with a recognizer—often an enzyme for things like glucose or lactate, or an aptamer/antibody for hormones and drugs. When the target binds, the surface’s electrical behavior changes slightly. The patch reads that tiny change, sends it via Bluetooth to your phone, and on-device or cloud AI turns it into a trend you can act on. Fluid → binding → signal → insight.

Patches vs. watches/rings

Watches and rings are terrific at vitals and behavior—but they can’t do chemistry. Patches do the opposite: they measure molecules directly, updating over minutes rather than seconds because analytes need time to move and equilibrate. The win comes from combining them—biochemical truth from a patch, context from a wrist wearable. Together they can flag issues earlier and with fewer false alarms.

Who’s building

Category leaders Abbott and Dexcom continue to push continuous glucose monitoring forward. Biolinq recently showed that a new form factor—a needle-free, autonomous patch with a built-in display—can meet the bar, a milestone that expands how we think about design. Early-stage players like Adaptyx, exploring aptamer-based multi-biomarker sensing, and Pheal, developing a flexible “smart health patch” platform, highlight the breadth of approaches now in development.

A broader cast of innovators is moving fast behind them. Gentag has long pursued disposable wireless biosensor patches; Nemaura Medical is developing sugarBEAT®, a daily-wear glucose monitoring patch; Xsensio is building a transistor-based “Lab-on-Skin” platform for cortisol and other biomarkers; Nutromics is advancing DNA-based aptamer sensors for drug monitoring; Metyos is targeting metabolic health with minimally invasive sensors; Nix focuses on sweat-based hydration tracking; Profusa explores injectable hydrogel sensors with skin-mounted readers; Hydrosense is developing sweat sodium and hydration patches; and Persperity Health is working on sweat-based sensing systems that use real-time sweat analysis to monitor hydration, stress, ovulation and metabolic markers.. These companies differ in chemistry and form factor, but all share the same trajectory: moving from single-analyte prototypes to multi-analyte patches designed for real-world use.

Skin as the Gatekeeper (and why BOHLD leans in early)

Every smart patch lives or dies at the skin interface. The most common failure modes in field use aren’t exotic chemistry problems—they’re human ones: adhesion that lifts after a workout, rashes that end a wear trial, or drift from movement artifacts that turns clean signals messy.

Two dermatological conditions dominate. Adhesive Contact Dermatitis (ACD) is an allergic reaction to components in the adhesive system; it shows up as itch, redness, sometimes small blisters, and gets worse with repeated exposure. Irritant Contact Dermatitis (ICD) isn’t an allergy; it’s the skin reacting to friction, moisture, pH shifts, occlusion, external irritants, and wear time. ICD is especially common on multi-day patches.

Good skin prep and materials discipline make a measurable difference in comfort and data quality. Skin preparation should be tailored to the intended wear duration and sensor design. On the materials side, knowing your adhesives and backings—including MVTR (moisture vapor transmission rate) and RET (evaporative resistance)—helps balance breathability with hold. BOHLD’s role is helping select adhesives with lower sensitizer risk that fit the wear duration, choosing backings that breathe and manage fluid accumulation, planning wear-time and placement, and designing protocols that real people can follow.

We also bring expertise in back-end analysis—reviewing skin irritation events during clinical trials or wear testing, tracing their biological or material basis, and recommending practical design or protocol changes to resolve them. Beyond advising on materials and design, BOHLD serves on clinical-trial safety boards for smart-patch programs, monitoring skin events in real time, guiding mitigations, and helping sponsors keep studies compliant and on track. By bridging dermatology and device engineering, we help teams anticipate problems early, respond effectively when they arise, and carry programs from prototype through approval with confidence

Dermatology for the Intersection of Skin and Technology

At BOHLD, we believe innovation in wearables only succeeds when the skin is part of the design equation from day one. Whether you’re building the next glucose patch or a multi-analyte platform for cardiac care, bring dermatology into the conversation early. The biology is ready. The market is ready. BOHLD makes sure the skin is ready too.