Research On The Application Of Peptide Nucleic Acid And Carbon Dots Interaction In Biosensors

Peptide nucleic acid is a deoxyribonucleic acid analog with many excellent properties,including the ability to bind to structured nucleic acid targets,excellent biological and chemical stability,and strong specific recognition capabilities.In addition,the uncharged backbone of peptide nucleic acids can be uniquely designed for experiments that cannot be done with oligonucleotides or negatively charged backbone analogs.In recent years,the application of peptide nucleic acids in nanotechnology has received extensive attention and has gradually become an important substitute for deoxyribonucleic acid.Carbon dots are a new type of fluorescent carbon nanomaterials with a size of less than 10 nm.Because of their strong luminescent properties and good solubility,they have received widespread attention.Compared with organic dyes and traditional semiconductor quantum dots,carbon dots have the advantages of resistance to photobleaching,easy surface modification,high solubility,and strong chemical inertness.In addition,due to its excellent biological characteristics such as low toxicity and good biocompatibility,carbon dots have broad application prospects in biosensors,bioimaging,biomolecule detection,and drug delivery.In this paper,the peptide nucleic acid probe main chain is uncharged,with high binding affinity and strong specificity,the fluorescence emission characteristics of carbon dots and easy functionalization modification,to jointly construct a biosensing platform for nucleic acid molecule detection and identification.The research content mainly has two directions:1.Peptide nucleic acid regulates fluorescent energy resonance transfer between carbon dots/gold nanoparticles to detect DNA.The carbon dots fluorescence prepared by the solvothermal method can be quenched by the gold nanoparticles.Since PNA can aggregate the gold nanoparticles,the fluorescence quenching intensity decreases.When the target DNA appears in the system,PNA and DNA form a stable double-stranded structure,the gold nanoparticles are in a dispersed state,and the carbon dots fluorescence is quenched,thereby realizing the detection of the target2.Covalently coupled carbon dots-peptide nucleic acid bioprobe for miRNA detection.The carbon dots and peptide nucleic acid are covalently coupled into a carbon dots-peptide nucleic acid(CDs-PNA)biological probe.Order carboxyfluorescein(FAM)labeled DNA probe,namely FAM-DNA,FAM-DNA and CDs-PNA bioprobe partially complementary sequence and hybridize in buffer solution,at this time the carbon dots and FAM fluorescence energy resonance transfer,FAM fluorescence intensity is enhanced.When the target miR-21 appears,the FAM-DNA is replaced,and the FAM fluorescence intensity decreases.Therefore,by measuring the change of FAM fluorescence signal intensity,the concentration of target miR-21 in the system can be quantified.