Photoresponsive CHA-Integrated Self-Propelling 3D DNA Walking Amplifier within the Concentration Localization Effect of DNA Molecular Framework Enables Highly Efficient Fluorescence Bioimaging

Abstract

While three-dimensional (3D) DNA walking amplifiers hold considerable promise in the construction of advanced DNA-based fluorescent biosensors for bioimaging, they encounter certain difficulties such as inadequate sensitivity, premature activation, the need for exogenous propelling forces, and low reaction rates. In this contribution, a variety of profitable solutions have been explored. First, a catalytic hairpin assembly (CHA)-achieved nonenzymatic isothermal nucleic acid amplification is integrated to enhance sensitivity. Subsequently, one DNA component is simply functionalized with a photocleavage-bond to conduct a photoresponsive manner, whereby the target recognition occurs only when the biosensor is exposed to an external ultraviolet light source, overcoming premature activation during biodelivery. Furthermore, a special self-propelling walking mechanism is implemented by reducing biothiols to MnO 2 nanosheets, thereby propelling forces that are self-supplied to a Mn 2+ -reliant DNAzyme. By carrying the biosensing system with a DNA molecular framework to induce a unique concentration localization effect, the nucleic acid contact reaction rate is notably elevated by 6 times. Following these, an ultrasensitive in vitro detection performance with a limit of detection down to 2.89 fM is verified for a cancercorrelated microRNA biomarker (miRNA-21). Of particular importance, our multiple concepts combined 3D DNA walking amplifier that enables highly efficient fluorescence bioimaging in live cells and even bodies, exhibiting a favorable application prospect in disease analysis.

Sensitive fluorescence assay of chloramphenicol coupled with two-level isothermal amplification using a self-powered catalyzed hairpin assembly and entropy-driven circuit

“…21 To achieve better sensitivity, some isothermal amplification techniques have been coupled with aptamers, such as the hybridization chain reaction (HCR), rolling circle amplification (RCA), catalytic hairpin assembly (CHA) and entropy-driven circuit (EDC). 22–27 Isothermal amplification reactions of nucleic acids have emerged as promising alternatives for signal amplification, which can rapidly and efficiently amplify signals with constant temperature. 28 So far, they have been widely used for the bio-sensing of various targets such as ions, small molecules, DNA, RNA, proteins and cells.…”

Distance-Based Visual miRNA Biosensor with Strand Displacement Amplification-Mediated DNA Hydrogel Assembly

“…Quantitative reverse transcription PCR (qRT-PCR) requires complicated primer designs for short targets; Northern blotting is less sensitive and accurate. The development of convenient and reliable detection approaches is still challenging . Recently, isothermal strategies have been utilized for amplified detection. , For example, Hu et al fabricated a fluorescent method for miRNA assay based on a flow cytometry measurement.…”