Detection of Brain-Derived Neurotrophic Factor (BDNF) with a Sandwich Assay on a Plasmonic Chip

Abstract

  Brain-derived neurotrophic factor (BDNF) has been studied for one of candidate proteins for brain disorder. Its detection has been performed with Enzyme-Linked Immunosorbent Assay (ELISA) at present. However, developments of more rapid BDNF detection system using a small amount blood sample has been demanded and it is important to find the anti-BDNF antibody with highly affinity. In this study, BDNF was rapidly detected with the enhanced fluorescence in the sandwich assay prepared on the Ag/ZnO-coated plasmonic chip. We used protein-protein interaction among two peptides constituting BDNF, Mature-BDNF and Prodomain-BDNF, for detecting Mature-BDNF. As for the capture part, Prodomain-BDNF linked with anti-ZnO antibody was immobilized to the ZnO surface of a plasmonic chip. As the detection part, primary antibody (monoclonal or polyclonal antibody) and secondary labeled IgG antibody were used. The detailed analysis of the primary antibody provided the important information on the BDNF detection. Compared with large nonspecific adsorption between Prodomain-BDNF and primary polyclonal antibody, monoclonal antibody was found to show the specific affinity with Mature-BDNF. Mature-BDNF was quantitatively detected with the monoclonal antibody on the plasmonic chip until the concentration lower than that detectable on the glass slide.