NCCR Bio-Inspired Materials researchers from the University of Fribourg have developed a groundbreaking iteration of the fluorescence microscope utilizing smartphone technology. Both highly affordable and portable, their device could be used to perform rapid medical tests outside hospital facilities.

Invented more than a century ago, fluorescence microscopes are essential tools in biology and medicine. Since the 1990s, these microscopes have been able to detect single molecules, a milestone recognized with the 2014 Nobel Prize. This level of sensitivity allows scientists to observe and track individual molecules by attaching tiny fluorescent tags to them. It reveals details that would otherwise be hidden in the crowd, letting us see what a single molecule is doing and helping us understand life’s processes and materials at the most fundamental level. This knowledge is particularly important in medicine, driving advances such as earlier disease detection and the development of new drugs. It is also widely used in biology, chemistry, physics, nanotechnology, and biotechnology. Nevertheless, fluorescence microscopes used in research and diagnostic laboratories have their drawbacks: they are heavy, cumbersome, expensive, and require trained users.

To make fluorescence microscopes more widely accessible, NCCR PI Prof. Guillermo Acuna of the University of Fribourg’s physics department chose to harness the power of smartphones. “These devices have a number of advantages,” he explains. “They are mass-produced, relatively inexpensive, and have excellent image sensors as well as strong data-processing capabilities.” It is thanks to these features that smartphones are paired with medical applications for health monitoring, or used for rapid field testing, bringing lab-quality diagnostics to remote or underserved areas.

Smartphone-compatible fluorescence microscopes themselves have been around for a decade. Their sensitivity has steadily improved, but so far, they have been unable to detect individual molecules. To “correct this short-sightedness,” a team of researchers led by Acuna, developed the concept relying on a novel laser excitation method and the use of the raw RGB data from the smartphone camera. “After unlocking the ultimate level of detection with our smartphone-based microscope, we can implement super-resolution techniques and demonstrate an eleven-fold improvement in resolution. Meaning that we were able to pinpoint the localization of single molecules within 86 nanometers (a thousand times smaller than the size of a hair, 0.000086 mm),” explains Dr. Mariano Barella. This is important because users can distinguish between structures that would otherwise appear as a single, blurry region, detect individual molecules more reliably, and create clearer images of cellular structures, bacteria, and viruses, for example.

This ingenious device already exists in a compact physical form. Its designers managed to make the innovative fluorescence microscope extremely portable, weighing just 1.2 kg with a volume smaller than a shoebox (11 cm × 22 cm × 12 cm). It is an easy-to-use, stand-alone unit powered by a power bank, which can be connected to any smartphone with a camera. Built with components that cost less than €350, far less than traditional fluorescence microscopes, which can run into hundreds of thousands. The Fribourg researchers believe their fluorescence microscope could also be used to analyze cancer cells, examine fresh tissue samples, or detect hazardous substances in the environment. These tests could be carried out anywhere, even without medical infrastructure, with the results transmitted to remote servers and analyzed by medical professionals or using tools such as artificial intelligence. According to the researchers, this could transform diagnostics by making them faster, more reliable, and more widely accessible, while also contributing to disease prevention. “To give just one example,” says Dr. Morgane Lorétan, who carried out her PhD in the Acuna group, “our device could allow a doctor to quickly determine whether a patient’s symptoms are caused by a bacterium or a virus — avoiding the misuse of antibiotics.”

Lorétan’s research has already been recognized with the Fribourg School of Management’s 2023 Innovation Challenge award. The results were recently published in the open-access journal Nature Communications, and the technology is currently being patented.

Reference: Loretan, M.; Barella, M.; Fuchs, N.; Kocabey, S.; Kołątaj, K.; Stefani, F. D.; Acuna, G. P. Direct Single-Molecule Detection and Super-Resolution Imaging with a Low-Cost Portable Smartphone-Based Microscope. Nat Commun 2025, 16 (1), 8937. https://doi.org/10.1038/s41467-025-63993-z