Versatile Luminol/Dissolved Oxygen/Fe@Fe₂O₃ Nanowire Ternary Electrochemiluminescence System Combined with Highly Efficient Strand Displacement Amplification for Ultrasensitive microRNA Detection

Abstract

Herein, a versatile ECL biosensor was fabricated for ultrasensitive detection of microRNA-21 (miRNA-21) from cancer cells based on a novel H 2 O 2 -free electrochemiluminescence (ECL) system (luminol/dissolved oxygen/Fe@Fe 2 O 3 nanowires). Compared with the previously reported coreaction accelerator that needed a negative potential to produce reactive oxygen species (ROS), these newly discovered Fe@Fe 2 O 3 nanowires could generate ROS in the detection solution immediately without the application of voltage, which narrowed down the detection potential range to avoid side reactions, favoring their practical application in biological systems. Especially, the Fe@Fe 2 O 3 nanowires could produce H • for activating dissolved oxygen into ROS to improve the ECL intensity dramatically, which initiates a novel pathway to promote the generation of ROS for the ECL system. In addition, an original strand displacement amplification coupled with strand displacement reaction (SDA-SDR) was developed to improve the conversion efficiency of the target for sensitive detection of miRNA-21. By virtue of the SDR, a quadruple quenching effect was achieved through each output DNA strand of SDA; hence, the nucleic acid signal amplification efficiency was effectively enhanced. As expected, on account of the superb activation performance of Fe@Fe 2 O 3 nanowires and the outstanding amplification efficiency of the SDR-SDA strategy, the fabricated ECL biosensor realized ultrasensitive detection of miRNA-21 with a detection limit down to 52.5 aM. The established ECL sensing platform ushered a new route for H 2 O 2 -free detection and a promising biomarker assay method for clinical diagnosis.

Electrochemiluminescence DNA Biosensor for HBV Based on Coralloid Poly(Aniline‐Luminol)‐MWCNTs and Catalysis of Ferrocene

“…Meanwhile, Figure 6B shows that luminol (curve a) had a small oxidation peak at 0.5 V, and the current of the oxidation peak increased in the presence of ferrocene (curve b). The ECL behaviour was due to that luminol was electrooxidized to luminol radical L⋅ − , and dissolved oxygen was reduced to O 2 ⋅ − ; then L⋅ − reacted with O 2 ⋅ − to generate excited‐state 3‐aminophthalate (AP 2−* ), which underwent a radiative reaction and released luminescence [26]. In the presence of Fc, Fc was electrooxidized to Fc + at low potential, and Fc + oxidized luminol to a high energy state, which was favourable to the following electro‐oxidation of luminol and subsequent ECL reaction with dissolved oxygen, and the ECL signal was enhanced.…”

Materialistic Interfaces with Nucleic Acids: Principles and Their Impact

“…The nucleic acids skills contained HCR, [161] DNAzyme, [162] circle rolling amplification, [163] catalytic hairpin assembly (CHA), [164] and strand displacement amplification (SDA). [165] Lin et al also developed the photoelectrochemical biosystems via the alternation of photosensitive materials. Previously, his group identified that Cu(I)-formed coordination polymer exhibited visible-light absorption and its proper band edge position enables attractive performance forming p-n junction with TiO 2 .…”

Nucleic acid isothermal amplification-based soft nanoarchitectonics as an emerging electrochemical biosensing platform

“…Further, with the aid of a highly efficient SDA amplification strategy in the solution, ultrasensitive detection for miRNA was realized with a detection limit down to 52.5 aM. 66…”