A New Method Of Electrochemiluminescence Biosensing Based On Nucleic Acid Cycle Amplification

Electrochemiluminescence?ECL?is a chemiluminescence technology induced by electrochemical reactions.Due to the advantages such as low detection limits,wide range,multi-parameter analysis,and fast speed,ECL technology has became a powerful analytical tool for ultra-sensitive detection in biological sciences.Nucleic acid amplification methods are nucleic acid-assistant signal amplification strategies.Smart design and efficient applications of various nucleic acid molecule-based recycling amplification techniques have emerged as most promising tools.ECL method integrated with nucleic acid amplification strategy,provides greatly enhanced sensitivity and selectivity for the targets in complicated biological samples,including blood,urine,saliva,tissues,and even living cells.In this paper,two ECL biological analysis methods with nucleic acid amplification strategies have been successfully established and used in bioanalysis.The contents are listed as follows:1.A portable electrochemiluminescence bipolar electrode array for the visualized sensing of Cas9 activityCRISPR/Cas9 has already become a powerful tool for genomic manipulation.Herein we develop a point-of-care platform for rapid and visible determination of Cas9 activity.A bipolar electrochemiluminescence?ECL?biosensor platform consists of an electrode array fabricated on a glass substrate and a PDMS layer act as a sample cell.DNA probes are modified on electrode and hybridization chain reaction?HCR?is applied to introduce ferrocene labeled DNA.The CRISPR/Cas9 system can recognize the immobilized DNA probes and cleave them from the electrode surface,as well as the labeled H1 and H2,so the cleavage activity is closely related to the labeled ferrocene.The modified electrode is embodied in a closed bipolar system,so that the oxidation reaction on sensing poles could be detected by the anodic ECL reactions on isolated luminescent poles due to charge balance,tuning the activity of Cas9 into ECL signals.This portable,integrated and convenient platform turns Cas9 activity into visible signals with high throughput,which is meaningful for the discovery of a new CRISPR/Cas9 system or additional Cas9inhibitors.2.Ultrasensitive electrochemiluminescence detection of helicobacter pylori nucleic acidA targeted cycle RCA reaction triggered by target DNA in helicobacter pylori is designed,resulting in massive tandem periodic C-rich DNA chains.Electrochemically generating Ag NCs are synthesized on the DNA chains,which can catalyze the reduction of S₂O₈^2-.Meanwhile,CdS quantum dots and the coreactant S₂O₈^2-form an ECL luminescence system to generate ECL signals,which changes obviously with the interfacial depletion of Ag NCs and S₂O₈^2-.This proposed biosensor holds great potential for further application in biomedical research and early clinical diagnostics.