Infrared imaging of an A549 cultured cell by a vibrational sum-frequency generation detected infrared super-resolution microscope.

We performed infrared (IR) spectroscopic imaging of molecular species in cultured cell interiors of A549 cells using in-house developed vibrational sum-frequency generation detected IR super-resolution microscope. The spatial resolution of this IR microscope was approximately 1.1 microm, which exceeds the diffraction limit of IR light. Therefore, we clearly observed differences in the signal intensity at various IR wavelengths which appear to originate from the differing IR absorptions of specific vibrational modes, and reveal the distribution of molecular species in the single cell. These results were never imaged with the conventional IR microscope.