Constructing DNAzyme-driven three-dimensional DNA nanomachine-mediated paper-based photoelectrochemical device for ultrasensitive detection of miR-486-5p.

As a unique class of dynamic nanostructures, biomimetic DNA walking machines that exhibit geometrical complexity and nanometre precision have gained great success in photoelectrochemical (PEC) bioanalysis. Despite certain achievements, the slow reaction kinetics and low processivity severely restrict the amplification efficiency of the DNA walker-mediated biosensors. Herein, by taking advantage of efficient DNA rolling machines, a three-dimensional (3D) DNA nanomachine-mediated paper-based PEC device for speedy ultrasensitive detection of miR-486-5p was successfully constructed.

Tetrahedral DNA Nanostructure-Engineered Paper-Based Sensor with an Enhanced Antifouling Ability for Photoelectrochemical Sensing.

Herein, a newly designed two-in-one tetrahedral DNA (TDN) nanostructure with an antifouling surface and backbone-rigidified interfacial tracks was developed for highly sensitive and selective detection of miRNA-182-5p. The well-regulated TDN tracks were assembled onto the surface of the TiO/MIL-125-NH-functionalized paper electrode, which efficiently avoided the obstacle of DNA strand tangling and decreased the probability of suspension during the walking process, thus greatly promoting the moving efficiency of DNA walkers. More interestingly, the TDN-modified sensing interfaces demonstrated incomparable antifouling ability against protein samples and interfering miRNAs due to the strong hydrophilic capacity and special molecular conformations, which addressed the dilemma of low sensitivity from traditional antifouling coating strategies.

Photothermal-Reagent-Triggered Visual Thermoresponsive and Quantized Photoelectrochemical Dual-Signal Assay.

In vitro biosensing chips are urgently needed for early-stage diagnosis and real-time surveillance of epidemic diseases. Herein, a versatile zone with photothermal effects is implanted in the miniature space of a collapsible lab-on-paper photoelectrochemical biosensor for on-site detection of microRNA-141 in body fluids, which can flexibly interconnect the traditional photocurrent signal with functional temperature response. The visualized thermoresponsive results are enhanced by the exciton energy conversion between FeO nanoparticles (FeO NPs) and formed Prussian blue nanoparticles under near-infrared irradiation, which not only presents heat energy gradient variations but also generates color changes.

Paper-Based Bipolar Electrode Electrochemiluminescence Platform Combined with Pencil-Drawing Trace for the Detection of M.SssI Methyltransferase.

Herein, a hand-drawing paper-based bipolar electrode (BPE) electrochemiluminescence (ECL) platform for M.SssI methyltransferase (M.SssI MTase) assay was proposed via employing high electrocatalytic Pt@CeO as an ECL co-reaction accelerator and pencil-drawing graphite electric circuits as wires and electrodes.

A Target-Driven Self-Feedback Paper-Based Photoelectrochemical Sensing Platform for Ultrasensitive Detection of Ochratoxin A with an InS/WO Heterojunction Structure.

Currently, developing versatile, easy-to-operate, and effective signal amplification strategies hold great promise in photoelectrochemical (PEC) biosensing. Herein, an ultrasensitive polyvinylpyrrolidone-treated InS/WO (InS-P/WO)-functionalized paper-based PEC sensor was established for sensing ochratoxin A (OTA) based on a target-driven self-feedback (TDSF) mechanism enabled by a dual cycling tactic of PEC chemical-chemical (PECCC) redox and exonuclease III (Exo III)-assisted complementary DNA. The InS-P/WO heterojunction structure with 3D open-structure and regulable topology was initially in situ grown on Au nanoparticle-functionalized cellulose paper, which was served as a universal signal transducer to directly record photocurrent signals without complicated electrode modification, endowing the paper chip with admirable anti-interference ability and unexceptionable photoelectric conversion efficiency.

Engineering paper-based visible light-responsive Sn-self doped domed SnO nanotubes for ultrasensitive photoelectrochemical sensor.

Exploring novel photoactive materials with high photoelectric conversion efficiency plays a crucial role in enhancing the analytical performance of paper-based photoelectrochemical (PEC) biosensor. SnO, which possesses higher photostability and electron mobility, can be regarded as a promising photoactive material. Herein, paper-based one dimensional (1D) domed SnO nanotubes (NTs) have been developed with the template-consumption strategy.