Fig. 5.

Fluorescence lifetimes of (a) the acceptor AF750 and (b) the donor QD655-SA vary as the base number of oligonucleotide increases. Excitation: 490 nm; emission: $785/62\mathrm{nm}$ bandpass filter for (a) and $650/60\mathrm{nm}$ bandpass filter for (b). B2T: the sample was incubated in borate buffer and then diluted with Tris buffer. B2P: the sample was incubated in borate buffer and then diluted with PBS buffer. B2T + NaCl: 140 mM NaCl was added into the B2T sample.