A rapid and visual turn-off sensor for detecting copper (II) ion based on DNAzyme coupled with HCR-based HRP concatemers

Abstract

To solve the requirement of on-site, rapid, and visual detection of copper (II) (Cu2+) in aqueous solution, a turn-off sensor for detecting copper (II) ion was developed based on Cu2+-dependent DNAzyme as the recognition element and hybridization chain reaction (HCR)-based horseradish peroxidase (HRP) concatemers as the signal amplifier and the signal report element. The detection unit, which was composed of the immobilized Cu2+-dependent DNAzyme coupled with HCR-based HRP concatemers via Waston-Crick base pairing, could catalyze hydrogen peroxide (H2O2) via TMB, generating obvious green color and turning yellow after sulfuric acid termination with optical absorption at 450 nm. Upon Cu2+ addition, the substrate strand of the Cu2+-dependent DNAzyme concatenated with the HCR-based HRP complex was irreversibly cleaved, efficiently causing dramatic reduction of the detection signal. Under optimal conditions, the detection signal decreased with the concentration of Cu2+ in 5 min, exhibiting a linear calibration from 0.05 to 3 μM with a detection limit of 8 nM. The sensor also displayed a high selectivity for Cu2+ given the specificity and anti-interference of the detection unit, and this system was applicable for monitoring Cu2+ in real water samples. Generally speaking, the proposed sensor exhibits good potential in environment surveys.

Metal oxide QD based ultrasensitive microsphere fluorescent sensor for copper, chromium and iron ions in water

“…Accordingly, the ZCM microsphere sensors can be applied selectively and sensitively for detection of metal ions. Especially ZCM microsphere shows far better sensitivity towards Cu 2+ mostly by a factor 100 and Cr 6+ mostly by a factor of 10 as compared to those reported earlier [44][45][46][47][48][49] (Table 3).…”

DNAzymes in biological detection and gene therapy

“…(c) The third generation Pb 2+ sensor [21] . (d) The Pb 2+ sensor based on the single-strand DNAzyme [22] 1.1.2 Cu 2+ DNAzyme Cu 2+ DNAzyme是一种DNA-cleaving DNAzyme, 其切割作用需要在Cu 2+ 的协助才能完成 [23] , 因此可 以用于检测Cu 2+ . 如图3(a)所示, Lu课题组 [24] 基于此 [25] 基于如图3所示的Cu 2+ DNAzyme,…”

Dual Catalytic Hairpin Assembly-Based Automatic Molecule Machine for Amplified Detection of Auxin Response Factor-Targeted MicroRNA-160

“…Besides genetic molecules in living systems, DNA is now also known as a versatile tool in the fields of biochemical analysis and nanomaterials [28][29][30][31]. Due to the advantages of programmability, controllability, and diversity of base-pairing, a variety of DNA nanostructures have been assembled and found spectacular applications in designing DNA sensing probes, providing numerous opportunities for reliable detection of various target analytes, such as DNA, RNA, metal ion, and protein [32][33][34][35][36][37]. For example, Deng et al [38] developed a rolling circle amplification (RCA)-based amplification technology for miRNA detection with high specificity.…”