Study On The Mechanism Of Immunosensing Detection Based On Nanocomposites

Early diagnosis of disease is essential for the treatment and management of disease,helping to prevent or reduce disease progression and maximize the chances of successful treatment while reducing treatment and social costs.Related studies have shown that excessive or insufficient secretion of serum thyroxine（3,5,3,5′-tetraiodothyronine,T4）can affect human metabolism and physiological functions.In addition,serum tau-441 is a major component of the neuronal endoskeleton protein tau,which can be used as a biomarker for Alzheimer’s disease（AD）and can be used in combination with clinical symptoms and brain imaging to diagnose and detect AD.Although there are many methods to detect T4 and tau-441 protein,there are still problems in actual samples limitations such as low selectivity,low sensitivity and poor anti-interference ability.In recent years,immunosensors have received more and more attention in clinical diagnosis because of their high sensitivity,high specificity,rapid detection,and high cost effectiveness,etc.Nanomaterials can improve the sensitivity and selectivity of immunosensors,and in this thesis,based on the study of immunosensing detection mechanism of nanocomposite materials,different immunosensing platforms were constructed to detect T4 and tau-441 proteins,as follows:（1）The synthetic route of T4 compounds was improved by using a new catalytic system to synthesize 1,2-dioxetane derivatives（3-（2-Spiroadamantane）-4-methoxy-4-（3-phosphoryloxy）phenyl-1,2-dioxetane,by replacing the conventional seven-step method with a three-step method.AMPPD）,was used to achieve high sensitivity detection of T4 in serum.The experimental results showed that the synthesized T4 compounds were thermally stable and did not differ significantly from natural T4,and there was no difference between the synthesized AMPPD and other products.The immunoassay constructed in this paper has a wide linear range（5～300 ng/m L）,high accuracy（recovery up to 103%）and high specificity.The proposed chemiluminescent immunosensor for the detection of T4 shows potential for good stability and sensitivity in clinical diagnostic detection of T4.（2）MWCNT-Cu₃（PO₄）₂-BSA composites were synthesized by hybridization of copper nanoflowers and multi-walled carbon nanotubes（MWCNT）,and a sandwich method electrochemical immunosensor with multiple signal amplification was established for achieving highly specific and sensitive detection of tau-441 protein.The detection range of the constructed electrochemical immunosensor was 0.0004μg/m L～6μg/m L,and the detection limit was 11.47 pg/m L.In addition,the reproducibility and stability of the immunosensor were good,and the cost effectiveness was high,which provided a new idea for the early in vitro diagnostic detection of AD.