A research team from Helmholtz Munich and the Technical University of Munich (TUM) has developed a microscopy method that can be used to differentiate and map lipids in living cells without chemical labeling. These include cholesterol and sphingomyelin, among others. The technique uses hyperspectral medium-infrared light and optoacoustic detection to generate a molecular fingerprint of the lipids.

Until now, visualizing certain lipids in living cells has been difficult. Conventional fluorescence microscopy requires specific fluorescent markers for each lipid class, which are complex to develop and can interfere with the natural function of lipids. The new method called HyFOPM (hyperspectral medium-infrared optoacoustic microscopy) circumvents these problems.

The principle: The sample is illuminated with pulsed medium-infrared light at several wavelengths. Certain lipids absorb light, creating a minimal rise in temperature that produces ultrasonic waves. These are captured and converted into spectral images. A computer-aided analysis uses this to create maps of the lipid distribution in the cell.

The decisive factor is the use of the so-called fingerprint region in the infrared spectrum. In this area, absorption patterns are formed that are characteristic of the molecular structure and spatial arrangement of lipids. This allows even chemically very similar lipid types such as glycerophospholipids and sphingomyelin to be clearly distinguished from each other.

The method puts minimal strain on the cells and enables marker-free measurements directly in living cells for the first time. Comparisons with established infrared spectroscopy confirmed the reliability of the chemical fingerprints generated.

The researchers see long-term applications in basic research and medicine. The technique could help to better understand disease processes, monitor metabolic activities and identify new biomarkers for diseases such as cardiometabolic syndrome. The next steps are to accelerate the method and test it in complex cellular systems with the aim of later application in humans.

The results were published in the journal “Nature Methods”. The work was led by Prof. Vasilis Ntziachristos (Helmholtz Munich and TUM). The first author is Dr. Francesca Gasparin from the Institute of Biological and Medical Imaging at Helmholtz Munich and TUM.

Original paper:

Gasparin et al., 2026: Differentiation of sphingomyelin and cholesterol by hyperspectral mid-infrared detection of single-bond vibrational modes in the fingerprint region. Nature Methods. DOI: 10.1038/s41592-026-03025-w

Editor: X-Press Journalistenbüro GbR

Gender Notice. The personal designations used in this text always refer equally to female, male and diverse persons. Double/triple naming and gendered designations are used for better readability. ected.