Catalytic Beacons for the Detection of DNA and Telomerase Activity

Abstract

DNA and telomerase activity are detected by a DNAzyme generated upon hybridization and opening of a functional catalytic beacon.

Polymeric Membrane Neutral Phenol-Sensitive Electrodes for Potentiometric G-Quadruplex/Hemin DNAzyme-Based Biosensing

“…The hybridization of the target DNA with the recognition sequence could open the hairpin structure and release the G-rich sequence to assemble into the peroxidasemimicking G-quadruplex DNAzyme in the presence of hemin ( Figure 4A). 28 As shown in Figure 4B, by using the electrode responsive to the p-MOP oxidation, potential responses proportional to the concentration of the target DNA (1 to 100 nM) were obtained and the target DNA at a concentration as low as 0.2 nM could be detected. For the noncomplementary DNA (DNA3), however, negligible changes in the potential responses as compared to that of the blank solution were observed even at a high level of 100 nM (data not shown), which confirms that the potential signals were induced by the specific hybridization of the target DNA with the probe DNA.…”

Split DNA Enzyme for Visual Single Nucleotide Polymorphism Typing

“…4 This DNA enzyme was used for the design of allosterically regulated sensors for nucleic acids, AMP, and lysozyme that allow colorimetric or luminescent readouts. 5 To construct a binary probe, the sequence of the peroxidase-like DNA enzyme ( Figure 1A) was split into two halves, the deoxycytidine was removed, and the analyte binding arms were added to each half via triethylene glycol linkers ( Figure 1B). In the absence of nucleic acid analyte strands α and β exist predominantly in the dissociated form (at certain concentrations and buffer conditions), while assembling in a Gquadruplex structure and acquiring peroxidase activity when hybridized to the adjacent positions of the analyte ( Figure 1C).…”

Optical and electrochemical detection of a verotoxigenic E. coli gene using DNAzyme-labeled stem-loops

“…Moreover, their structures can be modulated for the adoption of active or inactive states. These versatile characteristics allow the combination, in a single DNA molecule, of both a recognition element and a catalytic label, as is the case of a peroxidase DNAzyme [3] combined with another DNA strand which acts as a biorecognition element [4]. Although this analytical strategy is attractive for the development of biosensors, its practical use can be hampered by a low sensitivity due to the lower catalytic activity of peroxidase DNAzymes when compared to peroxidase proteins.…”

“…Optical detection has been the preferred means of transduction for the development of DNAzyme-based biosensors, usually with the use of ABTS, a reducing agent which becomes greenblue upon oxidation [4,[6][7][8][9]. On the other hand, electrochemical transduction has been chosen when DNA strands were immobilized onto electroactive surfaces [10][11][12].…”