Highly Luminescent and Self-Enhanced Electrochemiluminescence
of Tris(bipyridine) Ruthenium(II) Nanohybrid and Its Sensing Application
for Label-Free Detection of MicroRNA
posted on 2019-09-26, 17:07authored byJing Ye, Guoyong Liu, Mengxia Yan, Qiuju Zhu, Liping Zhu, Jianshe Huang, Xiurong Yang
Inspired
by the coreactive activity of carbon nanodots (CDs) and
branched polyethylenimine (BPEI) toward electrochemiluminescence (ECL)
of Ru(bpy)32+, a highly luminescent and self-enhanced
ECL nanohybrid (Ru-BCDs) was synthesized through covalently linking
BPEI-coated carbon dots (BCDs) with Tris (4,4′-dicarboxylic
acid-2,2′-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)32+). The composition and morphological characterization
demonstrated that the spherical Ru-BCDs particles with 12.1 ±
1.4 nm diameter were obtained. The enhanced ECL property of Ru-BCDs
was proved to originate from the dual coreactive contribution of BPEI
and CDs as coreactants as well as the intramolecular electron transfer
process, which could shorten the electron transfer path and minimize
energy loss. A carbon nitride nanosheet (CNN) was utilized to stabilize
the Ru-BCDs-modified glassy carbon electrode, which greatly improved
the stability of solid-state ECL. By utilizing
the affinity discrepancy of the CNN to single-stranded and double-stranded
nucleic acids, a label-free and signal-on ECL biosensor was constructed
for the determination of microRNA-133a (miR-133a), a potential biomarker
of acute myocardial infarction. The designed biosensor exhibited good
performance of miR-133a detection with a detection limit of 60 fM
and could be used for the detection of real human serum with satisfactory
results. The self-enhanced ECL nanohybrid with distinguished ECL efficiency
holds a promising prospect in biosensing and bioimaging applications.