In Situ 3D SERS Imaging of CO ₂ Reduction in Living Cells

Abstract The advancement of catalytic processes for therapeutic applications is pivotal to the development of next‐generation medical technologies. One of the major challenges in this field lies in elucidating the intracellular generation of small molecules, such as carbon monoxide (CO), nitric oxide (NO), and others, which possess significant therapeutic potential. In this study, in situ surface‐enhanced Raman spectroscopy (SERS) is employed to visualize and monitor the carbon dioxide (CO ₂ ) reduction process mediated by a rhenium coated gold nanoflower (Re@Au) catalyst within living cells. The findings provide direct spectroscopic evidence of CO ₂ reduction under intracellular conditions, demonstrating that CO can be catalytically generated from CO ₂ in the cellular environment. These results position SERS as an indispensable tool for investigating catalytic processes in biological systems, providing molecular‐level insights through the analysis of molecular fingerprint spectra that are typically beyond the capabilities of conventional microscopy techniques.