Aptamer-based Colloidal Gold Chromatography Strips For Rapid Detection Of Creatine Kinase-MB

For patients with myocardial infarction symptoms,Creatine Kinase-MB is important for clinical diagnosis.Colloidal gold chromatography strips,a representative of the simple,rapid and low-cost detection devices,enable more patients get timely diagnosis and treatments.Actually,researchers have used nucleic acid aptamers to replace antibodies in conventional colloidal gold chromatography strips,which further reduces the cost of diagnosis.Because aptamers are stable,cheap,easy to be modified and able to reaction a wider range of targets.At present,most of the aptamer-based detection methods are using thrombin as their targets,because during the past two decades,thrombin aptamers have been studied thoroughly.However,for other protein molecules,the use of nucleic acid aptamers to achieve detection is not easy,since there is no excellent nucleic acid aptamers for them,or existing aptamers cannot be directly applied to current detection methods,which means extra optimizations are required.Therefore,based on the existing researches,this research hopes to solve the problem that Creatine Kinase-MB,do not have aptamers,and then design and fabricate colloidal gold chromatography strips based on nucleic acid aptamers for the detection of Creatine KinaseMB.In this paper,firstly,a screening method based on SELEX(Systematic Evolution of Ligands by Exponential Enrichment)was established.Tosylactivated beads were utilized to immobilize and isolate Creatine Kinase-MB.Streptavidin beads are involved in the generation of single-stranded DNA.The relative affinity of DNA libraries with the Creatine Kinase-MB gradually increased with the increase of screening cycles,indicating that the screening method was successfully established.Then,ten kinds of Creatine Kinase-MB aptamers were obtained by this method,and the dissociation constants for the aptamers with Creatine Kinase-MB were between 0.81-272 nM.The results showed that aptamers with strong binding affinities were successfully screened,and these aptamers could be used for strips or other biosensors.Finally,Creatine Kinase-MB aptamers were applied to colloidal gold chromatography strips.The fabrication and testing conditions of strips were optimized.Finally,the LOD of the aptamer-aptamer sandwich strips was 82 nM,while the LOD of aptamer-antibody sandwich strips was 3.27 nM.Besides,the results showed that two kinds of aptamer-based colloidal gold chromatography strips were successfully constructed and their specificity was good.Bovine serum albumin,human serum albumin,immunoglobulin G,myoglobin and cardiac troponin I will not cause a positive test results.