title: A new controlled concept of immune-sensing platform for specific detection of Alzheimer's biomarkers.
abstract: We propose a concept of very specific immune-sensing platform dedicated to the quantification of biomarkers of Alzheimer disease (AD) in biological fluids. High sensitivity is required for the earliness of AD diagnostic, mainly based on clinical evaluation at present time. Accordingly, a controlled and adaptative surface functionalization of a silicon wafer with carboxylated alkyltrichlorosilane has been developed. The surface has extensively been characterized by AFM and X-ray Photoemissive Spectroscopy. The surface modification has been chemically assessed by XPS at each functionalization step. The survey spectra of silicon surface, after, 1, 3, 6 and 24 h of silanisation, highlight a significant enhancement of the functionalization efficiency upon time. The oxidation reaction has also been investigated by XPS and showed components related to the carboxylic group. AFM measurements pointed out a morphological modification consistent with a homogenous development of the carboxylic group and an almost protein monolayer on the surface. Moreover, we evaluated the biological activity of the grafted antibodies involved in (AD) biomarker detection onto this silanized surface by fluorescent microscopy. A sandwich immunoassay dedicated to the sensitive detection of one biomarker of Alzheimer disease (AD), the amyloid peptide 1-42 (Aβ 1-42), was carried out. The results demonstrated that the controlled silanized surface provides a novel and viable way to detect biomarkers with high specificity and open the route to an original development of immune-sensing applications on such surfaces.
authors.affiliation: Univ. Paris Sud, Institut d'Electronique Fondamentale, UMR CNRS 8622, Orsay F-91405, France. mehdi.ammar@u-psud.fr
authors.forename: M
authors.initials: M
authors.lastname: Ammar
authors.forename: C
authors.initials: C
authors.lastname: Smadja
authors.forename: L
authors.initials: L
authors.lastname: Giang Thi Phuong
authors.forename: M
authors.initials: M
authors.lastname: Azzouz
authors.forename: J
authors.initials: J
authors.lastname: Vigneron
authors.forename: A
authors.initials: A
authors.lastname: Etcheberry
authors.forename: M
authors.initials: M
authors.lastname: Taverna
authors.forename: E
authors.initials: E
authors.lastname: Dufour-Gergam
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D010446:Peptide Fragments / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42)