Chemically selective imaging of subcellular structure in human hepatocytes with coherent anti-stokes raman scattering (CARS) near-field scanning optical microscopy (NSOM)

Chemically selective imaging of human hepatocytes via intrinsic vibrational resonances with spatial resolution below the diffraction limit was carried out. The combination of coherent anti-Stoke Raman scattering (CARS) with near-field scanning optical microscopy (NSOM) was used for the imaging. Femtosecond, near-IR pulses produced CARS signals from hepatocytes and the signal was tuned to be resonant with C-H stretching frequencies. Results showed an image contrast with an optical spatial resolution ∼128 nm.