Authors: A. Papadopoulou-Bouraoui, M. Lejeune, J. Barrero-Moreno, A. Valsesia, M. Manso, D. Gilliland, G. Ceccone, and F. Rossi
Affilation: European Commission - JRC, Italy
Pages: 394 - 397
Keywords: quartz crystal microbalance, QCM, immunosensor, ellipsometry, AFM, TOF-SIMS, XPS, gold nanoparticles
During this study the QCM (Quartz Crystal Microbalance) crystal surface was functionalized in order to provide active amino groups, and serve as an active platform for antibody immobilization and the development of direct, label-free immunosensors. This was achieved through the formation of a Self Assembled Monolayer (SAM) using 4-aminothiophenol (4-ATPh) and through plasma deposition of allylamine polymer film (ALL). Two different antibody immobilization routes were investigated during this study. The first involved the use of glutaraldehyde as a linker, followed by protein A (PA) for optimal antibody orientation and consecutively highly sensitive antibody-antigen interaction. The second route involved the use manometer-sized gold (20 nm) particles (GNP) in combination with PA. Complete characterization of each activation step was performed by QCM, Ellipsometry, Atomic Force Microscopy, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and X-Ray Photoelectron Spectroscopy (XPS). The combination of surface analytical, optical and mass balance techniques is confirming the effectiveness of these immunosensor fabrication strategies.