Dual-Mechanism-Driven Ratiometric Electrochemiluminescent Biosensor for Methicillin-Resistant Staphylococcus aureus

Abstract

Design of a ratiometric method is a promising pathway to improve the sensitivity and reliability of electrochemiluminescent (ECL) assay, for which the signals produced at two distinct potentials change reversely as it is applied to the target analyte. Herein, a biosensor for ECL assay of methicillin-resistant Staphylococcus aureus (MRSA) was constructed by immobilizing porcine IgG for capturing MRSA onto an electrode that was precoated with β-cyclodextrin-conjugated luminol nanoparticles (β-CD-Lu NPs) as an anodic luminophore. MOF PCN 224 loaded with an atomically distributed Zn element (PCN 224/ Zn) was conjugated with phage recombinant cellular-binding domain (CBD) to act as a cathodic luminophore for tracing MRSA. After the formation of the sandwich complex of β-CD-Lu NPs-porcine IgG/MRSA/PCN 224/Zn-CBD on the biosensor, two ECL reactions were triggered with cyclic voltammetry. The anodic process of the β-CD-Lu NPs-H 2 O 2 system and the cathodic process of the PCN 224/Zn−S 2 O 8 2− system competed to react with reactive oxygen species (ROS) for producing ECL emission, which led to a reverse change of the two signals. Meanwhile, the overlap of the β-CD-Lu NPs emission spectrum and PCN 224/Zn absorption spectrum effectively triggered ECL resonance energy transfer between the donor (β-CD-Lu NPs) and the acceptor (PCN 224/Zn). Thus, a ratiometric ECL method was proposed for assaying MRSA with a dual-mechanism-driven mode. The detection limit for assaying MRSA is as low as 12 CFU/mL. The biosensor was applied to assay MRSA in various biological samples with recoveries ranging from 84.9 to 111.3%.

Cu Single-Atom Nanozyme-Mediated Electrochemiluminescence Biosensor for Highly Sensitive Detection of MicroRNA-622

“…In an attempt to optimize the reliability, reproducibility, and sensitivity of its detection, we aimed to construct a new type of electrochemiluminescence (ECL) biosensor. − ECL is a redox-triggered light emission process . The specific luminescent mechanism and electrochemical reaction process have led to the rapid development of ECL detection technology with the remarkable advantages of outstanding sensitivity and near-zero background. − Additionally, the excellent luminescence quantum yield and stability of luminol have made it a crucial luminophore in the development of ECL systems for biosensing and bioimaging. , In the conventional luminol ECL system, the introduction of hydrogen peroxide (H 2 O 2 ) as the coreactant facilitates the generation of reactive oxygen species (ROSs), such as the hydroxyl radical (OH • ), superoxide radical (O 2 •– ), and singlet oxygen ( 1 O 2 ), which accelerate the oxidation of luminol and amplify the ECL singal. , For this reason, there is a pressing demand for the introduction of efficient catalysts to facilitate the generation of interfacial ROS and construct high-performance ECL biosensors.…”