Ultrasensitive Protein Detection Using an Au/ZnO SPR-Based Biosensor
C.-C. Chang, S.-H. Lin, N.-F. Chiu, C.-W. Lin
National Taiwan University, TW
Keywords: ultrasensitive, Au/ZnO, tumor marker, Carbohydrate antigen 15.3
Abstract:In this study, we demonstrated that the Au/ZnO nanocomposite films could be effectively used to enhance the performance of SPR for the detection of tumor marker. Carbohydrate antigen 15.3 (CA15.3) tumor marker for breast cancer was chosen as a model analyte. We analyzed experimentally intensity response to the samples that had different concentrations (0.0125 U/ml to 160 U/ml) in pleural fluid to evaluate the detection capability of the Au/ZnO SPR-based biosensor. As a result, it was found that the linear range extended from 0.025 to 40 U/ml with correlation coefficient of R = 0.9531 and the limit of detection at S/N of 3:1 reached 0.025U/ml. Compared with the shift degree of SPR intensity by the specific binding event between antibody and antigen, the change of intensity on the Au/ZnO layers increased at least 2 fold more than that on the Au/Cr layers. In addition, we determined that the Au/ZnO layers had a detection limit 4 times lower than the gold / chromium (Au/Cr) layers that were widespread use of the sensing interfaces on SPR. In conclusion, the use of Au/ZnO films greatly enhanced the SPR signal after carrying out bimolecular interactions and presented high sensitivity and reproducibility.