DNAzyme-Triggered Visual and Ratiometric Electrochemiluminescence Dual-Readout Assay for Pb(II) Based on an Assembled Paper Device

Abstract

Currently, portable, low-cost, and easy to operate on-chip analytical units are urgently demanded to meet the requirement for point-of-care testing in resource-limited regions. Herein, a dual-mode lab-on-paper platform is presented, which integrates distance-based visualized readout with ratiometric electrochemiluminescence (ECL) assay in one device. The distance-based measurement is based on a brown visualized strip generated from the oxidation reaction of 3,3′-diaminobenzidine in the presence of H2O2 initiated by horseradish peroxidase (HRP). Notably, visualized semiquantitative results are displayed as the length of a brown bar chart directly on the devicewithout the need for any data processing or plotting steps, thus avoiding the error caused by the naked eye for distinguishing the color depth. On the contrary, a ratiometric ECL technique was employed for accurate analysis based on the specific biorecognition between Pb2+-dependent DNAzymes and targets. Concretely, upon addition of Pb2+ into the fabricated device, cleaved oligonucleotide fragments connected with HRP functionalized Au nanocubes could permeate through the cellulose on account of their size that is smaller than paper pores, quench the ECL signal of the CdS quantum dots because of resonance energy transfer, and synchronously boost the ECL intensity generated from luminol by catalyzing H2O2. As a consequence, satisfied prediction and accurate monitoring performance was obtained in the range 0.1–2000 nM and 0.01–2000 nM by measuring the length of colored product and the ratio of ECL intensity, respectively. The beneficial advantages of low cost, high efficiency, and the capacity to perform dual-mode assay qualify this innovative device for use with diverse applications.

Paper-based immunoassay based on 96-well wax-printed paper plate combined with magnetic beads and colorimetric smartphone-assisted measure for reliable detection of SARS-CoV-2 in saliva

“…In the era of sustainability, the use of paper-based devices and smartphone-assisted biosensors has established one of the main pillars in the diagnostics field. The use of paper in their design allows for: i) the fabrication of the plastic-free devices; ii) the loading of the reagents onto the cellulose network delivering a reagent-free measure; iii) the customization of microfluidics with an equipment-free system exploiting the capillarity of the paper; iv) a treatment-free measurement thanks to the filter paper which can treat the sample during the analysis, v) the possibility to be incinerated, rendering more sustainable the management of waste in the case of infected samples ( Cate et al, 2015 ; Hamedi et al, 2016 ; Caratelli et al, 2020 ; Grant et al, 2020; Antiochia, 2021 , Zhu et al, 2021 , Zhang et al, 2020 , Noviana et al, 2021 ). At the same level, smartphone-assisted devices can boost the acquisition of the signal by smartphone, avoiding the use of a dedicated instrument.…”

Mycotoxins Detection Based on Electrochemical Approaches

“…The ratiometric analysis technique can effectively normalize the changes of the external environment via self-correction, thereby improve the selectivity and sensitivity of detection [130]. Following the principle, Li et al designed ratiometric ECL sensor by two ECL emitters of Ru(dcbpy) 3 2 + and luminol for sensing DON [131].…”

Electrochemiluminescence Enhanced by the Synergetic Effect of Porphyrin and Multi‐walled Carbon Nanotubes for Uric Acid Detection

“…Ascribe to its high sensitivity, low background signal and wide measurement range [4,5], electrochemiluminescence (ECL) method can solve these above problems well and detect UA accurately. To date, inorganic metal complexes (Ru, Pt, Os) [6,7], aromatic organic compounds (anthracene, perylene, phenothiazine derivatives) [8][9][10][11][12], and nanomaterials (semiconductor quantum dots, metal nanoclusters, carbon quantum dots) [13,14] have been employed as ECL luminophores.…”