We have developed a new fluorescent ensemble probe comprising an ionic conjugate between water-soluble thioglycolic acid (TGA) capped CdTe quantum dots (QDs) and Ru(bpy)2(dppx)2+ for the dual-color detection of complementary double-stranded DNAs (dsDNA). To provide the platform for DNA detection, the Rucomplex was first employed as an effective fluorescence quencher to TGA capped QDs via photoinduced electron transfer process. Because of its strong binding affinity with Ru(bpy)2(dppx)2+, complementary dsDNA can break up the low fluoresced ionic ensemble, set free the luminescent QDs, and concomitantly generate the Ru(bpy)2(dppx) 2+ intercalated DNA complex. Thus, the recognition of dsDNA by Ru(bpy)2(dppx)2+ can be realized via both the restoration of QDs fluorescence and the emergence of a new fluorescence emission signal of the quencher-substrate at 609 nm, while single-stranded DNA, ribonucleic acid, bovine albumin serum, and biological relevant metal ions cannot produce the similar results. Therefore, a simple, fast, sensitive, and highly selective assay for dsDNA has been realized.
Scopus Subject Areas
- Analytical Chemistry