VENICE/MADRID - A team of researchers from Ca’ Foscari University of Venice and the Universidad Autónoma de Madrid has developed a groundbreaking technique that maps temperature in three dimensions within biological tissue, using invisible light and artificial intelligence.
The approach, just published in Nature Communications, could transform how we monitor temperature inside the human body, potentially improving early disease detection and treatment monitoring, without the need for costly or invasive imaging technologies.
“We’re turning optical distortions, usually considered a problem, into a source of information,” says Riccardo Marin, associate professor at Ca’ Foscari and one of the lead authors of the study. “With this method, we can detect both how hot a tissue is and how deep it lies beneath the surface.”
The method relies on luminescent nanothermometers, ultra-small particles made of silver sulfide (Ag₂S) that glow in the near-infrared when stimulated by light. The color and intensity of that glow depend on both the temperature of the particle and the amount of biological tissue the light has to pass through.
To decode these subtle spectral shifts, the team trained a dual-layer neural network on hundreds of hyperspectral images collected under different conditions. The result is a model that can reconstruct accurate, three-dimensional thermal maps of tissue, even under biologically complex scenarios.
Proof-of-concept experiments demonstrated the system’s ability to detect temperature gradients in both artificial tissue phantoms and real biological samples. The researchers also succeeded in mapping blood vessels in a living animal, marking the first time that remote, high-resolution 3D thermal imaging has been achieved using light alone.
While conventional techniques like fMRI or PET scans require costly equipment and specialized training, this new optical method is portable, safer, and significantly less expensive, potentially enabling diagnostics even outside the hospital setting.
Beyond temperature sensing, the same principles could be adapted to measure other vital parameters such as oxygen concentration and pH, by tailoring the optical properties of the nanoparticles.
“We believe this is just the beginning,” Erving Ximendes, assistant professor and Ramón y Cajal Fellow at the Universidad Autónoma de Madrid, adds. “Machine learning offers a powerful tool for navigating the complexity of real biological systems—far beyond what traditional models can achieve.”
The research also highlights the value of international collaboration and talent circulation. The project was initiated during Marin’s time at the Universidad Autónoma de Madrid and involved Anna Romelli, a Ca’ Foscari student on Erasmus mobility. The study now coincides with Marin’s return to Ca’ Foscari, his alma mater, as part of the university’s broader efforts to attract outstanding researchers and strengthen its global research networks.
Looking ahead: ERC-funded research into the cell’s inner life
This publication lays the foundation for a new five-year project led by Marin, who recently secured a €1.5 million ERC Starting Grant to advance luminescence nanosensing technologies. His project, MAtCHLESS, will develop next-generation sensors and imaging systems to monitor key intracellular parameters, such as temperature, pH, and oxygen, with unprecedented speed and resolution.
The project, carried out at Ca’ Foscari in close collaboration with Madrid-based colleagues, will explore the function of both mammalian cells and extremophile microbes, microorganisms that can withstand extreme conditions. It aims to deliver breakthroughs for medical diagnostics, biotechnology, and even astrobiology, deepening our understanding of life under extreme conditions, on Earth and possibly beyond.