AgAuS Quantum Dots as a Highly Efficient Near-Infrared Electrochemiluminescence Emitter for the Ultrasensitive Detection of MicroRNA

Abstract

Herein, the novel alloyed silver gold sulfur quantum dots (AgAuS QDs) with highly efficient near-infrared (NIR) electrochemiluminescence (ECL) emission at 707 nm were successfully prepared to construct a biosensing platform for ultrasensitive detection of microRNA-222 (miRNA-222). Interestingly, AgAuS QDs revealed excellent ECL efficiency (34.91%) compared to that of Ag2S QDs (10.30%), versus the standard [Ru­(bpy)3]2+/S2O8 2– system, which benefited from the advantages of abundant surface defects and narrow bandgaps by Au incorporation. Additionally, an improved localized catalytic hairpin self-assembly (L-CHA) system was developed to display an increased reaction speed by improving the local concentration of DNA strands, which addressed the obstacles of time-consuming traditional CHA systems. As a proof of concept, based on AgAuS QDs as an ECL emitter and improved localized CHA systems as a signal amplification strategy, a “signal on–off” ECL biosensor was developed to exhibit a superior reaction rate and excellent sensitivity with a detection limit of 10.5 aM for the target miRNA-222, which was further employed for the analysis of miRNA-222 from cancer cell (MHCC-97L) lysate. This work advances the exploration of highly efficient NIR ECL emitters to construct an ultrasensitive biosensor for the detection of biomolecules in disease diagnosis and NIR biological imaging.

Single-Atom Iron Doped Carbon Dots with Highly Efficient Electrochemiluminescence for Ultrasensitive Detection of MicroRNAs

“…Nevertheless, the ECL signal responses changed in value more rapidly in MHCC-97L than HeLa cells, suggesting that miRNA-222 was overexpressed in MHCC-97L and low expressed in HeLa. Meanwhile, the outcome was consistent with those reported by predecessors . In addition, a real-time quantitative polymerase chain reaction (qRT-PCR) also confirmed the high expression of miRNA-222 in MHCC-97L (Supporting Information section 2.9).…”

Electrochemiluminescence of Semiconductor Quantum Dots and Its Biosensing Applications: A Comprehensive Review

“…Based on the dual quenching effects, a sensitive ECL biosensing of microRNA is achieved with a wide linear range and acceptable selectivity. In addition, various signal amplification strategies have been widely explored to further improve the sensitivity of nucleic acid analysis, such as target-induced recycling amplification, cascade amplification strategies and strand displacement reactions [110][111][112][113][114][115][116]. For example, Yuan et al constructed a novel ECL biosensor to achieve the ultrasensitive detection of microRNA by combining target recycling amplification and double-output conversion strategies [110].…”

Co-Reactive Ligand In Situ Engineered Gold Nanoclusters with Ultra-Bright Near-Infrared Electrochemiluminescence for Ultrasensitive and Label-Free Detection of Carboxylesterase Activity

“…Near-infrared (NIR) ECL emitters possess intrinsic merits of almost zero background and deep tissue penetration, advancing their ECL interference-free sensing applications. To date, substantial NIR ECL emitters (organic dyes, , quantum dots, , metal complexes, − etc.) have been reported, but some limitations such as poor biocompatibility and heavy-metal toxicity persist.…”