Highly Sensitive Biochemical Analysis Based on a Single Molecule SERS Measurement Using a Gold Nanoparticle Dimer

We have proposed and demonstrated a novel digital counting surface-enhanced Raman spectroscopy (SERS) technique that measures multiple molecules in a sample solution based on a single molecule SERS, which allows us a label-free biochemical analysis with high identification capability and single-molecule sensitivity. This method realizes robust highly sensitive biochemical analysis by counting molecules one by one. This is expected to solve the problems of Raman intensity variation, low correlation between concentration and Raman intensity, and spectral superposition caused by multiple molecule mixed samples, which are the disadvantages of high-sensitivity SERS. This study characterized single-molecule measurements using gold nanoparticle dimers and demonstrated that multiple types of molecules can be discriminated and identified, and their molecular concentrations can be estimated, by digital counting SERS measurements.