Fig. 6

Investigation of combed double-stranded (DS) DNA immobilised on a glass surface using TERS. a Near-field spectra measured at three different positions, marked as 1, 2, and 3, along the line across the DS DNA bundle in b. The star highlights the characteristic Raman band of Si at 520 cm⁻¹ from the AFM tip. Spectrum integration time: 10 s. b AFM height image of a combed DS DNA bundle. c Intensity profiles obtained from the integration of near-field bands marked in a and AFM topography along the line in b. The values of full width at half maximum (FWHM) of the intensity profile of band γ5 and AFM topography are indicated. Reprinted with permission from reference [8]. Copyright 2014 American Chemical Society