Zinc–Metal Organic Frameworks: A Coreactant-free Electrochemiluminescence Luminophore for Ratiometric Detection of miRNA-133a

Abstract

Developing a coreactant-free ratiometric electrochemiluminescence (ECL) strategy based on a single luminophore to achieve more accurate and sensitive microRNA (miRNA) detection is highly desired. Herein, utilizing zinc−metal organic frameworks (Zn-MOFs) as the single luminophore, a novel dualpotential ratiometric ECL biosensor was constructed for ultrasensitive detection of miRNA-133a. The as-prepared Zn-MOFs exhibited simultaneous cathode and anode ECL emission. Furthermore, the Zn-MOFs were confirmed to be a multichannel ECL sensing platform with excellent annihilation and coreactant ECL emission. The corresponding ECL behaviors were investigated in detail. Benefiting from the hybridization chain reaction (HCR) amplification technology, N,N-diethylethylenediamine (DEAEA) was modified on hairpin DNA, and the gained products loaded with quantities of DEAEA enhanced the anodic ECL intensity of Zn-MOFs. In the presence of miRNA-133a, the ECL intensity ratio of anode to cathode (I a /I c ) was significantly increased, which realized the ultrasensitive ratiometric detection of miRNA-133a. In addition, without an exogenous coreactant, the biosensor revealed superb accuracy and stability. Under optimal conditions, the detection linearity of miRNA-133a was from 50 aM to 50 fM with a low detection limit of 35.8 aM (S/N = 3). This is the first work to use Zn-MOFs as a single emitter for reliable ratiometric ECL bioanalysis, which provides a new perspective for fabricating a ratiometric ECL biosensor platform.

Gold Nanoparticle-Bridge Array to Improve DNA Hybridization Efficiency of SERS Sensors

“…To further investigate the application of the proposed method, the microRNA-21 concentrations in HeLa and MCF-7 cells were detected (Figure g). Compared with previously reported works, − this work exhibited rapid DNA hybridization kinetics (Figure e).…”

Kinetics-Based Ratiometric Electrochemiluminescence Analysis for Signal Specificity: Case Studies of Piperazine Drug Discrimination with Au Nanoclusters

“…This fundamental principle is anticipated to be generalizable to other ECL luminophore–co-reactant systems for broader applications. Note that the kinetics-based ratiometric analysis differs fundamentally from classic ECL ratiometric methods where (1) either multiple ECL luminophores and/or energy transfer reagents or both cathodic and anodic reactions are necessary; and (2) the ECL signals are again almost exclusively under equilibrium or steady states, and additional recognition elements are required. − …”

Hydrophobic Localized Enrichment of Co-reactants to Enhance Electrochemiluminescence of Conjugated Polymers for Detecting SARS-CoV-2 Nucleocapsid Proteins

“…Such a method is simple, but the stability and repeatability problems of the ECL system cannot be ignored. 17 The in situ production of co-reactants by the enzyme-catalyzed reaction faces complex operation and harsh conditions of enzyme use, so its applications are limited. 18 Attaching co-reactants to the electrode surface can overcome the disadvantage of introducing the co-reactants described above, and some strategies such as covalent bonding and cross-linking have been adopted.…”

“…The most common method to introduce co-reactants is to add them directly into the detection solution. Such a method is simple, but the stability and repeatability problems of the ECL system cannot be ignored . The in situ production of co-reactants by the enzyme-catalyzed reaction faces complex operation and harsh conditions of enzyme use, so its applications are limited .…”

“…Yuan’s group also reported that the co-reactants could be enriched around the electrode surface by hydrophobic interaction between cholesterol and co-reactants . However, the hydrophobic localized enrichment of co-reactants described above was for the co-reactants present in the detection solution, which still caused stability and repeatability problems in the ECL system . Therefore, it is of great value to develop a material with an inner hydrophobic cavity for enriching co-reactants to achieve their immobilization on the electrode surface.…”