An ultrasensitive electrochemical aptasensor with autonomous assembly of hemin–G-quadruplex DNAzyme nanowires for pseudo triple-enzyme cascade electrocatalytic amplification

Abstract

We for the first time fabricate a pseudo triple-enzyme cascade electrocatalytic electrochemical aptasensor by using the alcohol dehydrogenase (ADH) as well as the autonomously assembled hemin-G-quadruplex that simultaneously acted as an NADH oxidase and HRP-mimicking DNAzyme.

DNA for Non-nucleic Acid Sensing

“…The idea remains the design of a nucleotide sequence comprising an aptamer portion (capture) and an input portion that triggers construction of a supramolecular DNA structure (DNA detection/ amplification). This principle has been successfully implemented using the CHA (Zheng et al 2012a), EDC (Cheng et al 2014a, b;Li et al 2013), and HCR Zhang et al 2013;Zhao et al 2013b;Song et al 2012;Yuan et al 2013) strategies.…”

An enzyme-free and label-free fluorescent biosensor for small molecules by G-quadruplex based hybridization chain reaction

“…The opened H2 can be used as a new initiator to hybridize with a new H1 and trigger the new H1 to be opened. Thus, H1 and H2 are cross-opened successively and self-assembled into long DNA nanowires incorporated with numerous G-quadruplexes [21,22,30,39], resulting in fluorescence enhancement after binding with NMM.…”

“…HCR not only provides an enzyme-free signal amplification method but also involves a unique assembly process, which works under mild conditions with no specific demand for ionic strength, pH or temperature. Nowadays, many studies combined the amplification capability of HCR with various sensing platforms and showed promising results for the detection of biomolecules such as DNA [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], microRNA [23,24], proteins [25][26][27][28][29][30][31], cells [32,33]. However, to this day there are few reports for the detection of small molecules [34][35].…”

An “Off–On” Electrochemiluminescent Biosensor Based on DNAzyme-Assisted Target Recycling and Rolling Circle Amplifications for Ultrasensitive Detection of microRNA

“…18 Such lead-requiring DNAzyme has been isolated in test tubes 19,20 and is highly affinitive for specific metal ions covering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Pb(II) [21][22][23] , Cu(II) 24 and Zn(II) 25,26 . A typical Pb 2+ -requiring DNAzyme design named "8-17" is consisted of a substrate strand (17DS) and an enzyme strand (17E) [21][22] 31,32 . In addition, the quenching of luminol ECL signal was also studied [33][34][35][36] .…”