title: Layer-by-layer generation of PEG-based regenerable immunosensing surfaces for small-sized analytes.
abstract: Small molecules (haptens) like pharmaceuticals or peptides can serve as targets for antibody binding in competitive immunoassay-based flow-through assays. In this work, a strategy for preparing polyethylene glycol (PEG) coatings for subsequent hapten immobilization on glass-type silica surfaces is presented and characterized in detail. Two substrates bearing terminal silanol groups were utilized, a glass slide and a silicon wafer. First, surfaces were thoroughly cleaned and pretreated to generate additional silanol groups. Then, a silane layer with terminal epoxy groups was created using 3-glycidyloxypropyltrimethoxysilane (GOPTS). Epoxy groups were used to bind a layer of diamino-poly(ethylene glycol) (DAPEG) with terminal amino groups. Finally, the low molecular weight compound diclofenac was bound to the surface to be used as model ligand for competitive biosensing of haptens. The elementary steps were characterized using atomic force microscopy (AFM), water contact angle measurement, grazing-angle attenuated total reflection (GA-ATR) FT-IR spectroscopy, and X-ray photoelectron spectroscopy (XPS). The data collected using these techniques have confirmed the successive grafting of the molecular species, evidencing, that homogeneous monolayers were created on the silica surfaces and validated the proposed mechanism of functionalization. The resulting surfaces were used to investigate polyclonal anti-diclofenac antibodies recognition and reversibility using quartz crystal microbalance with dissipation (QCM-D) measurements or an automated flow-through immunoassay with chemiluminescence (CL) read-out. For both techniques, recognition and reversibility of the antibody binding were observed. The stability of sensors over time was also assessed and no decrease in CL response was observed upon 14 days in aqueous solution. The herein presented strategy for surface functionalization can be used in the future as reproducible and reusable universal platform for hapten biosensors.
authors.affiliation: Chair for Analytical Chemistry and Institute of Hydrochemistry, Technische Universität München, Marchioninistr. 17, Munich, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Huebner
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 6, UMR CNRS 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France; CNRS, UMR 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France.
authors.forename: Maroua
authors.initials: M
authors.lastname: Ben Haddada
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 6, UMR CNRS 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France; CNRS, UMR 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Méthivier
authors.affiliation: Chair for Analytical Chemistry and Institute of Hydrochemistry, Technische Universität München, Marchioninistr. 17, Munich, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Niessner
authors.affiliation: Chair for Analytical Chemistry and Institute of Hydrochemistry, Technische Universität München, Marchioninistr. 17, Munich, Germany. Electronic address: dietmar.knopp@ch.tum.de.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Knopp
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 6, UMR CNRS 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France; CNRS, UMR 7197, Laboratoire de Réactivité de Surface, F75005 Paris, France. Electronic address: souhir.boujday@upmc.fr.
authors.forename: Souhir
authors.initials: S
authors.lastname: Boujday
mesh_terms: D000906:Antibodies / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D015374:Biosensing Techniques; D006241:Haptens / Q000737:chemistry* / Q000276:immunology; D049449:Luminescence; D018625:Microscopy, Atomic Force; D011092:Polyethylene Glycols / Q000737:chemistry; D058525:Quartz Crystal Microbalance Techniques; D012822:Silicon Dioxide / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000906:Antibodies; D006241:Haptens; D014867:Water; D011092:Polyethylene Glycols; D012822:Silicon Dioxide
keywords: Hapten; Immunosensor; Microarray; PEG coating; QCM-D; Regeneration