Highly Sensitive Genosensing Coupling Rolling Circle Amplification with Multiple DNAzyme Cores for DNA Walking

Abstract

Herein, a highly sensitive electrochemical genosensor is proposed by the construction of an innovative DNA walking machine. Generally, a number of tetrahedral DNA (TDNA)supported tracks and walkers are comodified on the electrode surface. DNA walking is inhibited in the absence of target DNA. After the interaction between a DNA walker strand and target DNA, a single-stranded primer sequence could be released, which initiates subsequent rolling circle amplification (RCA). The generated long single-stranded product contains multiple DNAzyme cores, which facilitate highly efficient cleavage of track strands and subsequent DNA walking. The electrode then loses the ability to localize silver nanoparticles (AgNPs) as the electrochemical species. Thus, when the reduced silver stripping current is recorded, a highly sensitive method for the detection of DNA is fabricated. Under optimal conditions, it achieves an admirable sensitivity with the limit of detection as low as 0.1 fM. Satisfactory specificity is also guaranteed. In addition, the practicality is further confirmed by applying human serum samples, which show great potential utility for clinical diagnosis.

Trace miRNA Assay Based on DNA Nanostructures Formed by Hybridization Chain Reaction and Gold‐Nanoparticle Tags

“…Although amplification‐free assays are convenient for practical applications, [19–21] in order to further improve the sensitivity, isothermal amplification techniques have been extensively investigated such as rolling circle amplification (RCA), [22] hybridization chain reaction (HCR), [23] ligase chain reaction, [24] and catalytic hairpin assembly (CHA) [25] . In addition, the application of nanomaterials have received great attention [26] .…”

Rolling Circle Amplification as a Universal Method for the Analysis of a Wide Range of Biological Targets

“… The most commonly used variants of solid-phase RCA: (a) capture of an NA target by the immobilized DNA probe, target-mediated ligation of the probe with the primer, and the initiation of RCA; (b) capture of an NA target by the immobilized DNA probe, the cyclization of the NA target, and the initiation of RCA; (c) recognition of a target other than NA by an immobilized receptor, formation of a sandwich complex with a conjugate of the receptor with the primer, and the initiation of RCA; (d) recognition of a biotarget other than NA by the immobilized receptor and FSS, which carries the primer, and initiation of RCA; (e) variant of the combination of RCA with the “DNA walker” technology [ 45 ]. …”

“…After the NA is fixed by probe no. 1, a cascade of repeated rounds of denaturation–annealing of NA structures and enzymatic reactions is triggered on the surface, leading to the synthesis of RCAPs [ 45 – 47 ].…”

Nanocomposite of electrochemically reduced graphene oxide and gold nanourchins for electrochemical DNA detection

“…Among different types of nanobiosensors, the electrochemical nanobiosensors of DNA comprise even more advantages, including higher accuracy, lower price, and a more simple fabrication process [ 9 , 10 , 11 ]. That is why electrochemical DNA biosensors have been used mostly in medical and agricultural detection strategies, and their applications are constantly growing day after day [ 11 , 12 , 13 ]. They also proved to be effective in the recent COVID‐19 pandemic for the detection of the virus [ 14 ].…”