title: Biosensors elaborated on gold nanoparticles, a PM-IRRAS characterisation of the IgG binding efficiency.
abstract: This work is focused on studying the grafting of gold nanoparticles (Np) on a cystamine self-assembled monolayer on gold, in order to build sensitive immunosensors. The synthesis and deposition of gold nanoparticles, 13 and 55 nm sizes, were characterised by combining Polarisation Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS), X-ray Photoelectron Spectroscopy (XPS) Surface Enhanced Raman Scattering (SERS), and Atomic Force Microscopy (AFM) which all indicated the formation of a dispersed layer of nanoparticles. This observation is explained by the compromise between the high reactivity of amine-terminated layers towards gold, and interparticle repulsions. Nps were then functionalised with antibody probes, and the recognition by an anti-rIgG was assayed both on planar and Np gold surfaces. The important result is that nanoparticles of 55 nm are preferable for the following reasons: they enable to build a denser and well dispersed layer and they increase both the number of receptors (IgGs) and their accessibility. Beside these geometric improvements, a net enhancement of the Raman signal was observed on the 55 nm nanoparticle layer, making this new platform promising for optical detection based biosensors.
authors.affiliation: Université Pierre et Marie Curie, Paris 6, UMR CNRS 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Morel
authors.forename: Souhir
authors.initials: S
authors.lastname: Boujday
authors.forename: Christophe
authors.initials: C
authors.lastname: Méthivier
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Krafft
authors.forename: Claire-Marie
authors.initials: CM
authors.lastname: Pradier
mesh_terms: D000906:Antibodies; D000915:Antibody Affinity; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006046:Gold; D007074:Immunoglobulin G; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D011485:Protein Binding; D013057:Spectrum Analysis / Q000295:instrumentation*; D013059:Spectrum Analysis, Raman
chemical_list: D000906:Antibodies; D007074:Immunoglobulin G; D006046:Gold