Researchers at the Université de Montréal and the Institut national de la recherche scientifique (INRS) have developed an innovative system that can detect skin cancer (melanoma) at a very early, still invisible stage. The technology, called SMEAR-ULM, uses a painless microneedle patch that inserts special nanoparticles under the skin. These particles form a temporary “smart tattoo” that works like an array of microscopic thermometers.

When irradiated with near-infrared light, the nanoparticles emit visible light, the lifetime of which depends directly on the local temperature. Since tumor cells have a higher metabolism and produce more heat, tiny temperature differences can be recorded and converted into a detailed thermal map. An ultra-fast imaging system makes this possible in a single imaging process with high spatial resolution and temperature sensitivity.

The researchers were able to detect micromelanomas after only four days – a stage at which conventional imaging methods still fail. Compared to conventional infrared methods, the new system offers significantly better accuracy and could reduce unnecessary biopsies in the future as well as improve early detection and targeted therapy selection.

In the long term, the technology could also be adapted to measure other physiological parameters such as pH or ion concentrations. The study was published in the journal Nature Sensors on 20 May 2026 and was supported by several Canadian funding organisations.

The researchers see great potential in this approach to revolutionize the diagnosis of melanoma and significantly improve early detection.

Explanatory video:

SMEAR-ULM: Detecting Invisible Melanomas via Intelligent Nanoparticle Tattoos

Original paper

«Single-shot microneedle-encoded upconversion lifetime mapping for real-time in vivo thermo-dermoscopy», by Yingming Lai et al., May 20 2026, Nature Sensors.

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