Target Recycling Transcription of Lighting-Up RNA Aptamers for Highly Sensitive and Label-Free Detection of ATP

We describe here a target recycling transcription of lighting-up aptamer strategy for detecting ATP in human serums in a label-free means with high sensitivity.ATP molecules specifically recognize the binding aptamer and result in the structure switching of the DNA assembly probes to imitate the target ATP molecule recycling cycles through the toehold-mediated strand displacement reaction,which causes the formation of many dsDNAs containing the RNA promoter sequences for subsequent transcription generation of large amounts of lighting-up aptamers.The organic dye,malachite green,then associates with these lighting-up aptamers to produce significantly enhanced fluorescence signals,which can sensitively detect ATP within a dynamic range from 10 to 500 nM in a label-free way.The sensing approach shows a detection limit of 7.3 nM and also has an excellent selectivity for ATP analogue molecules.In addition,this method can detect ATP molecules in diluted human serum samples sensitively,which proves the promising potential to diagnose ATP-related diseases.

Engineering Multipedal DNA Walker on Paper for Sensitive Electrochemical Detection of Plant MicroRNA

MicroRNAs (miRNAs) are vital regulators in both plants and animals. Therefore, it is highly desirable to develop portable and user-friendly biosensors for convenient and sensitive detection of miRNAs. Herein, a novel paper-based electrochemical biosensor was intelligently engineered for the detection of plant miRNA based on a smart DNA walking machine and λ-exonuclease (λ-Exo)-assisted target recycling amplification. Using TaMIR5086 as a target plant miRNA, the presence of TaMIR5086 could initiate the target recycling process and activate the DNA walker to move along the track on the paper. Then, numerous electroactive molecules-labeled single-strand DNA (ssDNA) would be released and adsorbed onto the surface of screen-printed electrode, generating a remarkably increased electrochemical signal. Benefitting from the dual amplification, the developed biosensor exhibits excellent analytical performance toward TaMIR5086 with a detection limit down to 0.37 pmol/L. Furthermore, the paper-based biosensor could be applied for the analysis of target miRNA in complex biological samples, which found great potential in the fields of miRNA analysis and plant biology research.