title: Surface characterization and efficiency of a matrix-free and flat carboxylated gold sensor chip for surface plasmon resonance (SPR).
abstract: We report the preparation and characterization of a matrix-free carboxylated surface plasmon resonance (SPR) sensor chip with high sensing efficiency by functionalizing a bare gold thin film with a self-assembled monolayer of 16-mercaptohexadecanoic acid (SAM-MHDA chip). The self assembled monolayer surface coverage of the gold layer was carefully evaluated and the SAM was characterized by infrared reflection absorption spectroscopy, X-ray photoemission spectroscopy, atomic force microscopy, X-ray reflectivity-diffraction, and SPR experiments with bovine serum albumin. We compared the SPR signal obtained on this chip made of a dense monolayer of carboxylic acid groups with commercially available carboxylated sensor chips built on the same gold substrate, a matrix-free C1 chip, and a CM5 chip with a ~100 nm dextran hydrogel matrix (GE Healthcare). Two well-studied interaction types were tested, the binding of a biotinylated antibody (immunoglobulin G) to streptavidin and an antigen-antibody interaction. For both interactions, the well characterized densely functionalized SAM-MHDA chip gave a high signal-to-noise ratio and showed a gain in the availability of immobilized ligands for their partners injected in buffer flow. It thus compared favourably with commercially available sensor chips.
authors.affiliation: Laboratoire de Physique de l'Etat Condensé, UMR 6087 CNRS-Université du Maine, molecular landscape and biophotonic horizons, Avenue Olivier Messiaen, 72085 Le Mans, France.
authors.forename: L
authors.initials: L
authors.lastname: Roussille
authors.forename: G
authors.initials: G
authors.lastname: Brotons
authors.forename: L
authors.initials: L
authors.lastname: Ballut
authors.forename: G
authors.initials: G
authors.lastname: Louarn
authors.forename: D
authors.initials: D
authors.lastname: Ausserré
authors.forename: S
authors.initials: S
authors.lastname: Ricard-Blum
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology; D019921:Biotinylation; D002264:Carboxylic Acids / Q000737:chemistry*; D002417:Cattle; D043169:Endostatins / Q000032:analysis / Q000276:immunology; D006046:Gold / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism; D018625:Microscopy, Atomic Force; D010169:Palmitic Acids / Q000737:chemistry*; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000032:analysis / Q000378:metabolism; D019809:Streptavidin / Q000378:metabolism; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013499:Surface Properties; D056928:X-Ray Absorption Spectroscopy
chemical_list: C450319:16-mercaptohexadecanoic acid; D000941:Antigens; D002264:Carboxylic Acids; D043169:Endostatins; D007074:Immunoglobulin G; D010169:Palmitic Acids; D012710:Serum Albumin, Bovine; D006046:Gold; D019809:Streptavidin