1 research outputs found
Quenching of the Electrochemiluminescence of Tris(2,2′-bipyridine)ruthenium(II)/Tri‑<i>n</i>‑propylamine by Pristine Carbon Nanotube and Its Application to Quantitative Detection of DNA
In this study, we describe the quenching of electrochemiluminescence
(ECL) of trisÂ(2,2′-bipyridine)-rutheniumÂ(II)Â(RuÂ(bpy)<sub>3</sub><sup>2+</sup>)/tri-<i>n</i>-propylamineÂ(TPA) at pristine
multiwall carbon nanotube (MWNT) modified glassy carbon (GC) electrode.
Even though the faradic current of the RuÂ(bpy)<sub>3</sub><sup>2+</sup>/TPA system and the oxidation of TPA obtained at pristine MWNT-modified
GC electrode is enhanced compared with those at the bare GC electrode,
the intensity of ECL produced at MWNT electrode is smaller than that
at GC electrode. For testing the possible reason of quenching, a comparison
of ECL behavior of RuÂ(bpy)<sub>3</sub><sup>2+</sup>/TPA at pristine
MWNT and acid-treated, heat-treated, and polyethylene glycol (PEG)-wrapped
MWNT-modified GC electrode is studied. The results demonstrate that
the oxygen-containing groups at the surface of MWNT and the intrinsic
electron properties of MWNT are considered to be the major reason
for the suppression of ECL. The comparison also demonstrates that
this quenching is related to the distance between MWNT and RuÂ(bpy)<sub>3</sub><sup>2+</sup>/TPA. Utilizing this essential quenching mechanism,
a new signal-on DNA hybridization assay is proposed on the basis of
the MWNT modified electrode, where single-stranded DNA (ssDNA) labeled
with RuÂ(bpy)<sub>3</sub><sup>2+</sup> derivatives probe (Ru-ssDNA)
at the distal end is covalently attached onto the MWNT electrode.
ECL signal is quenched where Ru-ssDNA is self-organized on the surface
of MWNT electrode; however, the quenched ECL signal returns in case
of the presence of complementary ssDNA. The developed approach for
sequence-specific DNA detection has good selectivity, sensitivity,
and signal-to-background ratio. Therefore, the quenching of the ECL
of RuÂ(bpy)<sub>3</sub><sup>2+</sup>/TPA system by the pristine MWNT
can be an excellent platform for nucleic acid studies and molecular
sensing