An ‘intelligent tattoo’ may detect skin cancer before it appears

Detecting melanoma, one of the most aggressive forms of skin cancer, is a major challenge for oncologists. Because of their small size, the melanomas are usually excluded from clinical inspection, which leaves the threat unwatched. Researchers from Université de Montréal, scientists at Université du Québec’s Institut national de la recherche scientifique (INRS) have developed an “intelligent tattoo” to solve this problem. 

Called SMEAR-ULM, it is a high-tech system that can detect skin cancers at their earliest stages by measuring tiny temperature variations at the surface of the skin. The findings of the study were published in Nature Sensors yesterday. 

Experts note that the melanoma incidence is rising worldwide and early diagnosis is critical to improve survival rates. Currently, diagnostic approaches rely on visual examination followed by biopsies. These procedures are invasive and sometimes unnecessary. 

By enabling rapid, direct, and non-invasive assessment of suspicious skin lesions, this technology could reduce unnecessary biopsies, improve early diagnostic accuracy, and support clinical decision-making. 

“Our goal is to provide a minimally invasive tool to detect very small, but still aggressive melanomas,” said Jinyang Liang, the study’s senior author, who specialises in ultrafast imaging and biophotonics at INRS. 

A temporary “tattoo” 

At the core of the system is a patch of painless microneedles that deposits specialised nanoparticles just beneath the skin. These nanoparticles form a temporary “intelligent tattoo” that behaves like an array of microscopic thermometers. 

When illuminated with near-infrared light, the nanoparticles emit visible light. Crucially, the lifetime of this light emission—how long it lasts—depends directly on local temperature. Because cancer cells consume more oxygen and nutrients than healthy cells, they produce additional heat, which can be detected through this optical signal. 

Using an ultrafast imaging system, SMEAR-ULM captures all this information in a single high-speed snapshot, generating a detailed thermal map with submillimeter spatial resolution and sub-degree temperature sensitivity. 

“We capture all the necessary information for an instantaneous temperature map in a single shot, which makes the method fast and robust to continuously monitor abnormal thermal responses in small melanomas—even within complex in vivo conditions,” said first author Yingming Lai, an INRS postdoctoral fellow who completed their PhD in Energy and Materials Sciences at INRS.

With this approach, the researchers successfully detected micro‑melanomas as early as four days old. This is a stage at which they are typically far too small to be identified by conventional imaging techniques. 

Conversely, conventional thermal imaging methods rely on infrared technologies that suffer from limited spatial resolution and high noise levels. As a result, they usually only detect tumours larger than 5 millimeters—lesions already visible to the naked eye.  

The approach also redefines the role of temperature in cancer detection. While tumours are known to generate more heat due to their higher metabolic activity, this signal has traditionally been too imprecise to use as a diagnostic marker. SMEAR-ULM changes that by turning subtle thermal variations into a highly sensitive and measurable signal. 

“Even though this study was conducted in mice, this animal model replicates the genetic changes observed in human melanomas and could therefore potentially benefit patients,” added Sylvain Meloche, a researcher at UdeM’s Institute for Research in Immunology and Cancer and co-corresponding author of the study.