Pleitez, M. A. et al. Nat. Biotechnol. https://doi.org/10.1038/s41587-019-0359-9 (2019).

Vibrational imaging methods like Raman and infrared microscopy can yield information-rich images of unlabeled cells based on chemical differences among biomolecules. Compared to Raman, mid-infrared spectroscopy and microscopy benefit from biomolecules having high absorbance cross sections, but are limited in biological applications by the absorption from water in these wavelengths, which weakens the measured signal. Pleitez et al. have developed mid-infrared optoacoustic microscopy (MiROM), which combines the benefits of mid-IR excitation and optoacoustic detection. In MiROM, ultrasound waves generated by mid-IR absorption, which are much less attenuated than photons, are measured for improved signal-to-noise and contrast-to-noise imaging. The researchers demonstrate that their approach could be used for diffraction-limited resolution imaging of proteins, carbohydrates and lipids in adipocytes and pancreatic tissue.