Novel Single-Enzyme-Assisted Dual Recycle Amplification Strategy for Sensitive Photoelectrochemical MicroRNA Assay

Abstract

Herein, a novel single-enzyme-assisted dual recycle amplification strategy based on T7 exonuclease (T7 Exo) and a strand-displacement reaction (SDR) was designed to fabricate a photoelectrochemical (PEC) biosensor for sensitive microRNA-141 (miRNA-141) detection with the use of laminar bismuth tungstate (Bi2WO6) as photoactive material. Compared with a traditional enzyme-assisted dual recycle amplification strategy, the presented method could effectively refrain the enzyme interference reaction, reduce environmental sensitivity, and save cost. Here, hairpin DNA1 (H1) decorated on magnetic beads (MB) hybridized with target miRNA-141 to form an H1/miRNA-141 heteroduplex. With the introduction of hairpin DNA2 (H2)-labeled SiO2 (H2-SiO2), SDR was triggered between H2-SiO2 and H1, thus miRNA-141 was displaced from the H1/miRNA-141 heteroduplex and an H1/H2-SiO2 duplex was formed, realizing the reuse of the target. In the presence of T7 Exo, the H1/H2-SiO2 duplex was digested with the release of output DNA-SiO2. To enhance the target conversion rate, H1-MB was intactly released and cycled, which could initiate more T7 Exo digestion and free abundant output DNA-SiO2. Through such a process, a tiny miRNA-141 could induce substantial output DNA-SiO2, effectively improving the target amplification efficiency and detection sensitivity of a PEC biosensor. Furthermore, Bi2WO6 was modified on an electrode to provide a superior initial PEC signal due to its excellent electronic transformation capacity. With the introduction of output DNA-SiO2, the hairpin structure of H3 on the electrode was opened, making SiO2 close to the electrode surface, which significantly decreases the PEC signal. This work first established the PEC biosensor featuring a single-enzyme-assisted dual recycle amplification process for sensitive detection of biomarkers.

Ultrasensitive Photoelectrochemical Biosensor Based on Novel Z-Scheme Heterojunctions of Zn-Defective CdS/ZnS for MicroRNA Assay

“…The fabrication process is displayed in Scheme . Antecedent to modification, the surface of GCE was polished with alumina powder (0.3, 0.05 μm) and then ultrasonically cleaned in ultrapure water and ethanol alternately . Next, the pretreated mirror-like GCE was first coated with 10 μL of photoactive material CSZS–V Zn , followed by drying at 37 °C for obtaining a lightly yellow film.…”

“…Antecedent to modification, the surface of GCE was polished with alumina powder (0.3, 0.05 μm) and then ultrasonically cleaned in ultrapure water and ethanol alternately. 29 Next, the pretreated mirror-like GCE was first coated with 10 μL of photoactive material CSZS−V Zn , followed by drying at 37 °C for obtaining a lightly yellow film. After that, 10 μL of the as-prepared Au NPs was dripped on the electrode surface and desiccated at 37 °C to obtain a Au layer.…”

Colorimetric assay based on iron(iii) ions triggering the aggregation of a poly(tannic acid) coated Au nanocomposite for carbonic anhydrase II detection

“…1,2 However, developing rapid and cost-effective detection techniques with high sensitivity and specificity is always challenging. Compared with the various detection methods relying on professional and sophisticated analysis instrumentation, [3][4][5][6][7] the colorimetric assays, which is easy to monitor with the naked eye, are constantly improved for satisfying home-testing or on-site detection. [8][9][10][11][12] For this assay, numerous types of sensors such as Au nanoparticles, [13][14][15][16] quantum dots 17,18 and silver nanoparticles 19,20 have been explored.…”

Photoelectrochemical Assay Based on SnO2/BiOBr p–n Heterojunction for Ultrasensitive DNA Detection

“…The bare glassy carbon electrode (GCE) was pretreated based on the previous method to achieve a mirror-like surface. 33 Then, 10 μL of ■ RESULTS AND DISCUSSION Characterization of the Prepared Materials. The microstructures and morphologies of the synthesized materials were characterized by scanning electron microscopy (SEM).…”