Disease Detection Study Based On Magnetoelastic DNA Sensor

With the development of social economy and the advancement of science and technology,people's life and work pressure are increasing,and there are more and more hidden diseases of physical diseases.Disease prevention,early diagnosis and treatment have become critical issues that need to be resolved.Traditional disease detection methods have the disadvantages of complicated instruments,higher detection costs,and longer time,and they are in short supply in remote areas and disease outbreak areas.Therefore,it is necessary to develop a small and portable sensor for highly sensitive and rapid detection of diseases.With the development of information,biology and materials science,biosensors came into being.Existing disease detection related biosensors have higher costs,larger instruments,and unsatisfactory sensitivity and stability.Magnetoelastic DNA biosensors based on magnetoelastic materials show many advantages:small and convenient,less sample required,low cost,simple experimental process,and easy mass production,etc.Therefore,the preparation and application of magnetoelastic DNA biosensors for disease detection is a very practical research topic.Combined with the advantages of magnetoelastic materials and DNA,this thesis uses magnetoelastic materials as the substrate,and performs surface functionalization design through competition mechanism,triple clip structure,and nanoparticle amplification signal.The magnetoelastic DNA biosensor for detecting carcinoembryonic antigen(CEA)and disease-related genes was constructed,and its sensing performance was verified as follows:1.A magnetoelastic DNA biosensor based on competition mechanism is proposed,which realizes highly sensitive and specific detection of CEA.The magnetoelastic chip is the substrate,the CEA aptamer is the specific recognition element,and the silver nanoclusters using DNA as the template(DNA-Ag NCs)are used to amplify the signal.The prepared magnetoelastic DNA biosensor was used to detect different concentrations of CEA.The resonance frequency offset was linear with the logarithm of the CEA concentration,the response range was2 pg/m L?6.25 ng/m L,and the sensitivity was 105.05 Hz/ng m L^-1,the limit of detection(LOD)is 1 pg/m L,which is lower than the minimum value of the normal reference range.The magnetoelastic biosensor has good specificity and stability,and has potential application value in clinical diagnosis.2.A magnetoelastic DNA biosensor based on signal amplification of gold nanoparticles(Au NPs)is proposed,which realizes highly sensitive and label-free detection of the most common mutant gene that causes?-thalassemia.Magnetoelastic DNA biosensors use a magnetoelastic material as a platform,and DNA sequences that are semi-complementary to the target sequence(t DNA)form the specific recognition layers.DNA signal probe modified gold nanoparticles(s DNA-Au NPs)are used for signal amplification and signal indicator,realizing label-free detection of t DNA.The offset of the resonance frequency of the magnetoelastic biosensor is linearly related to the logarithm of the t DNA concentration,ranging from 1.0×10^-8 M to 1.0×10^-12 M,and the LOD is 0.571 p M.The magnetoelastic DNA biosensor has the ability to distinguish between t DNA and mismatched DNA sequences.The magnetoelastic DNA biosensor also has good stability,and can be used as a potential tool for the determination of?-thalassemia.3.A magnetoelastic DNA biosensor was proposed to detect the vitamin K cyclooxygenase complex subunit 1(VKORC1)gene and guide the adjustment of warfarin dosage.The DNA that are semi-complementary to t DNA form the specific recognition layers,which meets the high detection requirements for single nucleotide polymorphisms(SNP)of the VKORC1 gene.The three-clamp structure based on the biotin-avidin reaction system is used to optimize the surface functionalization unit of the biosensor,and the avidin is introduced as a direct signal indicator and amplifier through the high specificity of biotin avidin to achieve label-free detection.The results show that the frequency response of the magnetoelastic DNA biosensor has a linear relationship with the logarithm of t DNA concentration from 1.0×10^-11 M to 1.0×10^-16 M,the LOD is 0.00389f M(S/N=3),and the sensitivity 45.7 Hz/p M.In addition,the magnetoelastic DNA biosensor also has good selectivity,stability and reproducibility.