Probing Amyloid β and the Antibody Interaction Using Atomic Force Microscopy

Amyloid beta (A beta) peptide is considered to be the critical causative factor in the pathogenesis of Alzheimer's disease (AD) because the hydrophilic molecules accumulated outside of the neural cells and results in the formation of highly toxicity amyloid plaque. In this study, we probed the interaction between A beta and the antibody using atomic force microscopy (AFM). We compared two kinds of antibodies which are the antibody for A beta 1-42 (antibody42) and the antibody for A beta 1-16 (antibody16). To detect the interaction between A beta and the antibodies, the single molecular force spectroscopy was carried out using A beta modified glass substrate and the antibodies modified AFM probes. In the results, the single A beta-antibody42 dissociation constant was estimated to be 5.2 x 10(-3) s(-1) and the single A beta-antibody16 dissociation constant was 2.8x10(-2) s(-1). The A beta-antibody42 showed 5.3 times longer bond life time compare with A beta-antibody16. It suggested that antibody42 is better choice for the A beta sensor development.