Detecting vibrational tags by infrared microscopy

The use of infrared (IR) photothermal microscopy is emerging for imaging chemical substances in various samples. Although the technique provides high sensitivity, the background from water absorption in biological samples makes it difficult to extract target molecules in the signal. To overcome this issue, we propose the use of a vibrational tag to detect target molecules with reduced background. We performed infrared photothermal imaging of chemical in liquid condition and confirmed that the photothermal signal was produced from the vibrational tag in the sample. The results also confirm the possibility of vibrational tag imaging by using IR photothermal microscopy.