Figure 4.
Two strategies for using Forster resonance energy transfer (FRET) to shift emission wavelength away from excitation wavelength. (A) Co-intercalated donor (blue) and acceptor (red) dyes allow efficient FRET to occur, but some donors must be displaced to accommodate acceptors. (B) Non-intercalated acceptor dyes (red spheres) linked to DNA termini allow FRET without displacing donor dyes. Note that efficient energy migration among intercalated donor dyes prior to energy transfer to an acceptor dye can occur in both formats.