An interdisciplinary research team, led by Assistant Prof. Jun Nishida and Associate Prof. Takashi Kumagai at the Institute for Molecular Science, has successfully observed vibrational spectra of single proteins, consisting of approximately 500 amino acid residues, using advanced measurement techniques based on near-field optical microscopy. This method utilizes light confined at the nanometer scale, allowing for the detailed analysis of extremely small samples, which was previously challenging with conventional infrared spectroscopy.