The Development Of A Novel Chemiluminiscence System And Its Application In Detecting Sequence-specific DNA And A Fluoroimmunoassay Method To Detect Breast Cancer Biomarkers

Sequence-specific DNA detection and immunoassay played an important role in early clinical diagnosis.Hence,it is important to develop novel methods for the detection of sequence-specific DNA and immunoassay.In the present study,we developed a novel chemiluminescence method to detect sequence-specific DNA and a fluorescence immunoassay method to detect breast cancer biomarkers.Firstly,a novel luminol-H2O2-HRP CL system which is enhanced by both bromophenol red and BSA was developed.This novel CL system showed higher sensitivity than p-Iodophenol(PIP)which is a classic enhancer used in luminol-H2O2-HRP CL system.Then the mechanism was discussed in the present study.The proposed CL system was employed for the detection of HBV related target DNA.The use of bromophenol red as enhancer and BSA as co-enhancer led to a detection limit as low as 0.4 fmol.Secondly,a fluorescent immunoassay was established to detect breast cancer biomarkers.This method is simple and needs no washing steps,and can be used for the noninvasive early diagnosis of breast cancer.The method is based on the fluorescence quenching function of graphene oxide(GO)and competitive binding of free breast cancer biomarker and GO-breast cancer biomarker conjugates on quantum dots(QDs)-antibody conjugates.In this study,antibody was modified on the surface of QDs to form QDs-antibody conjugates.Through the immunoreaction,the antibody labeled quantum dots will bind to the surface of GO which is modified with antigen leading to fluorescence quenching.On the other hand,in the presence of free breast cancer biomarker,the free antigen will compete with the antigen modified on the GO resulting in fluorescence recover.This fluorescence immunoassay was applied to detect CEA,CA153 and CA125.After condition optimization and method validation,the proposed method was used to the applied to the detection of CEA,CA153,and CA125 successfully.As the QDs used in this method will not interfere with each other at their maximum emission wavelength,the results of cross reaction showed that the proposed method can be used for the simutanous detection of three kinds of tumor markers.