An Electrochemiluminescent Immunosensor For Detection Of Cancer-related Indicators On Hollowed Nanomaterial Supporting Interface

The early diagnosis of tumor has important value and significance for the future treatment effect and prolonging life of patients.Carbohydrate antigen 19-9 is a common tumor marker,also known as gastrointestinal cancer-associated antigen,which is often used in the diagnosis and post-operative monitoring of pancreatic cancer.It is also abnormal in the serum of patients with gallbladder cancer,gastric cancer,colon cancer and so on.At present,ELISA is the main method to detect CA19-9,but this method is expensive and the detection process is complicated.Therefore,it is important to develop a simple and rapid detection method for detecting CA19-9 in cancer patients.In this paper,an ECL immunosensor was prepared for the detection of CA19-9.The details are as the follows:The first part:We have improved the traditional sol-gel method to prepare silica nanoparticles with a particle size of about 50 nm.The core-shell structure of SiO₂-PDA was obtained by self-polymerization of dopamine with this small size silica as template.The gold sol with a particle size of about 5 nm was prepared by improving the method of reducing chloroauric acid.The gold nanoparticles were grafted onto the surface of SiO₂-PDA material to obtain SiO₂-PDA-Au composite material.The hollow microsphere structure of PDA-Au was prepared by etching silicon dioxide with hydrofluoric acid.The obtained hollow microsphere structure of PDA-Au was used as an electrode material.The second part:PDA-Au/ITO material electrodes were prepared by one-step dropping method,and the preparation conditions and ECL parameters of the electrodes were optimized.The drop amount of PDA-Au on ITO is 30μL,the pH of the buffer solution is pH=8,the optimal upper limit potential is 1.2 V,and the optimal lower limit potential is-0.3 V.Five parallel electrodes were tested by CV.It was found that PDA-Au/ITO material electrodes had good reproducibility.The third part:The anti-CA19-9 was incubated on the PDA-Au/ITO material electrode,and the non-specific binding site was blocked with BSA to obtain the immunosensor bovine serum albumin（BSA）Anti-CA19-9/PDA-Au/ITO.The target CA19-9 was detected as an ECL signal probe.The results show that the quenching value of the ECL intensity is linear with the concentration of the target CA19-9.The detection range is 0.5 U/mL-80 U/mL with a detection limit of 0.10 U/mL.This kind of immunosensor has the advantages of strong specificity,high sensitivity,low cost and simple preparation.It is suitable for immunoassay。...