Characterization of Immunological Interactions at an Immunoelectrode by Scanning Electron Microscopy

Abstract

A method to visualize an immunointeraction occurring at an electrode surface by the use of scanning electron microscopy is demonstrated. A colloidal gold-labeled antigoat antibody was used for the visualization of two immunosensor platforms where an antiatrazine single chain antibody and an antibiotin were immobilized on the surface, respectively. Firstly, a silver enhancement treatment was optimized in order to improve the visualization of the gold label. Subsequently, protein distribution on the surface was evaluated in relation to the immobilization time. Finally, this method was adopted to evaluate specific immunological interactions. Comparing the images of the immunosensor surfaces with those of different control surfaces, it was established that the immunological interactions were effectively occurring at the electrode and it was also possible to gain an appreciation of the extent and distribution of the immunological interaction at the electrode surface and the level of non-specific binding occurring. Energy Dispersive X-ray (EDX) analysis was also performed for a qualitative evaluation of the atomic electrode surface composition.