Functionalization Of Porous Anodic Alumina Film In The Application Of Biochemical Analysis

Biosensors are composed of recognition elements and signal converters,which are used to monitor the biochemical processes occurring in vivo and in vitro.These biosensors have a wide application prospect in biochemical analysis,clinical examination,disease screening and other fields.The classic recognition elements are usually nucleic acid,peptide,protease,antibodies and cells.The common detection methods include electrochemical methods,spectroscopic analysis,etc.In recent years,academical community has developed many bioanalytical sensors which facilitates the building of novel methods in biochemical analysis field.However,when the detection process is cumbersome,the application of traditional detection methods in the actual sample detection is often hindered.The spatial confining effect of artificial nanostructures provides a new idea for the biosensors,among which the most typical bionic asymmetric nanochannels can recognize molecules through the surface and inner hole of the nanochannels.Therefore,this kind of sensor has the advantages of low cost,fast detection,high sensitivity and so on.This paper is to construct functionalized biomolecules(peptide and aptamer)on the surface of artificial ion nanochannel,which is used for biochemical analysis and detection of disease markers.The specific contents are as follows:1.Peptide self-assembly on the ion nanochannel for the analysis of MMP-2 in tumor extracellular matrixWe used biomimetic asymmetric nanochannels(porous anodic alumina film)to construct a model for the detection of matrix metalloproteinase-2 in extracellular matrix(ECM).To be more specific,the well-designed peptide sequence was modified on barrier layer of porous anodic alumina film which can self-assemble to nanofibers which greatly change the space steric hinderance.After reacting with MMP-2,the network was damaged,the difference can be recorded by electrochemical station.The detection range of method is 10 fg/m L-10 ng/m L,and the limit of detection is 6.6 fg/m L.The method of peptide-based ion nanochannel not only is valuable for clinical application for the detection of MMP-2 in tumor microenvironment,but also has good implications for the research and development of human intelligent sensors for the monitoring of other disease markers.2.Aptamer-specific ion nanochannels for the analysis of SARSCoV-2 spike proteinIn this part of our work,we used the aptamer of SARS-CoV-2 spike protein S1 subunit to design an assay for COVID-19.Firstly,we immobilize the aptamer of S1 protein on the surface of porous anodic alumina films.In the presence of S1 protein,aptamer can specifically bind to S1 protein and change the charge density and steric hindrance of the ion channel,which changes the ion rectification of the channel before and after the binding.The difference can be presented by the current-voltage curve of electrochemical workstation.This method can achieve the detection of SARS-CoV-2.Furthermore,the detection range was 0.001?1000 p M,and the limit of detection was0.138 f M(10.557 pg/L).In clinical pharyngeal swab samples,the detection results of this method are consistent with the PCR results.The aptamer used in this method contained only 24 nucleotides,which was easy to be synthesized,stable,and low in price.This method is simple in steps,short in detection time,high in sensitivity and does not require enzyme labeling,etc.Therefore,this method has great prospect in the clinical diagnosis of COVID-19.