June 21, 2024 | Researchers at the Karolinska Institute in Stockholm, Sweden, have developed a new device for detecting malignant melanoma. Melanoma affects about one million people every year across the world, and over the past two decades, cases of melanoma have significantly increased due to higher rates of exposure to ultraviolet radiation and climate change (Advanced Materials, DOI: 10.1002/adma.202403758). According to Onur Parlak, assistant professor in the Department of Medicine, Solna, Dermatology, and Venereology at the Karolinska Institute and one of the researchers of this study, it is predicted that melanoma cases will increase by as much as 80% in the near future.
The Device’s Design and How It Works
With cases expected to nearly double, a quick and efficient way to diagnose melanoma is needed. The research team created a patch equipped with microneedles that can identify tyrosinase (Tyr), an enzyme that is intricately involved in melanin production and is a critical biomarker for melanoma diagnosis, directly in the skin. By measuring Tyr levels directly in the skin, researchers can quickly identify changes linked to disease.
The main motivation behind the study was to produce a small epidermal patch that can be an alternative to traditional invasive and time-consuming diagnostic methods, such as taking biopsies in the clinic, followed by complementary laboratory-based testing, which requires trained professionals and expensive equipment.
Microneedles puncture the skin and are designed to be electrically conductive and mechanically stable by mixing polyurethane (PU) and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). Then, the microneedles’ surfaces are coated with a Tyr-responsive chemical probe that enables a specific oxidation reaction between Tyr and the probe (Advanced Materials, DOI: 10.1002/adma.202403758). When brought together in an electrical circuit, the five-millimeter-sized patch can test for Tyr (Advanced Materials, DOI: 10.1002/adma.202403758) in the skin. Patients and clinicians can then read the results on a computer or other measurement reader connected to the device via a cable.
Though the device was applied to a healthy human skin model, it can also be applied to suspicious areas of skin, such as oddly colored areas, shapes, moles, and so on. The patch is simply pressed down and can be removed “as easy as peeling a Band-Aid,” according to Parlak. The device is not meant for long-term use, but it can be reapplied. For example, a patient can test an area of regular, healthy-looking skin, take it off, and then apply it to another spot that looks suspicious. The measurement reading is done in less than a minute.
Incidentally, the reusability of the device was a pleasant—and important—discovery during the experiment. Typically, unless enzymes or different biorecognition elements are used, sensors saturate over time, giving them a short lifetime. But when the team applied low electrical voltages to the microneedle, the sensor surface—particularly Tyr-responsive probes—for their device was able to regenerate, Parlak explains.
Easily Accessible for Patients
Ultimately, the goal is to follow the same strategy as glucometers that measure blood sugar levels. Many glucometers have smartphone apps for patients to track their blood sugar levels and access their information. Parlak relays, “At this stage, we haven’t developed an application yet, therefore patients or viewers need to read out the values from the computer screen that the microneedle patch is connected to with the cable.”
There is also a possibility that the patch will be over-the-counter and commercially available like glucometers, but Parlak says, “It’s difficult to say at this stage... It’s out of the lab and depends on the market, requests, and investment.” He also elaborates that further clinical testing and trials are required.
For clinicians and other medical professionals, they can look forward to a valuable and versatile tool that can make the diagnosis process easier and more efficient. For patients, Parlak highlights the importance of the non-invasive nature of the patch and how it can provide patients comfort and compliance, as well as making it easier to monitor skin health without multiple trips to the clinic.
As for next steps, Parlak says, “There are a lot of things to be done further and enhancing the sensor functionality [is what] we are currently working on.”