title: High sensitivity protein assays on microarray silicon slides.
abstract: In this work, we report on the improvement of microarray sensitivity provided by a crystalline silicon substrate coated with thermal silicon oxide functionalized by a polymeric coating. The improvement is intended for experimental procedures and instrumentations typically involved in microarray technology, such as fluorescence labeling and a confocal laser scanning apparatus. The optimized layer of thermally grown silicon oxide (SiO(2)) of a highly reproducible thickness, low roughness, and fluorescence background provides fluorescence intensification due to the constructive interference between the incident and reflected waves of the fluorescence radiation. The oxide surface is coated by a copolymer of N,N-dimethylacrylamide, N-acryloyloxysuccinimide, and 3-(trimethoxysilyl)propyl methacrylate, copoly(DMA-NAS-MAPS), which forms, by a simple and robust procedure, a functional nanometric film. The polymeric coating with a thickness that does not appreciably alter the optical properties of the silicon oxide confers to the slides optimal binding specificity leading to a high signal-to-noise ratio. The present work aims to demonstrate the great potential that exists by combining an optimized reflective substrate with a high performance surface chemistry. Moreover, the techniques chosen for both the substrate and surface chemistry are simple, inexpensive, and amenable to mass production. The present application highlights their potential use for diagnostic applications of real clinical relevance. The coated silicon slides, tested in protein and peptide microarrays for detection of specific antibodies, lead to a 5-10-fold enhancement of the fluorescence signals in comparison to glass slides.
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare, CNR, 20131 Milano, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Cretich
authors.forename: Gabriele
authors.initials: G
authors.lastname: di Carlo
authors.forename: Renato
authors.initials: R
authors.lastname: Longhi
authors.forename: Cecilia
authors.initials: C
authors.lastname: Gotti
authors.forename: Natalia
authors.initials: N
authors.lastname: Spinella
authors.forename: Salvatore
authors.initials: S
authors.lastname: Coffa
authors.forename: Clelia
authors.initials: C
authors.lastname: Galati
authors.forename: Lucio
authors.initials: L
authors.lastname: Renna
authors.forename: Marcella
authors.initials: M
authors.lastname: Chiari
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000378:metabolism; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D007073:Immunoglobulin E / Q000097:blood* / Q000276:immunology; D009841:Oligonucleotides / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D040081:Protein Array Analysis / Q000379:methods*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D013194:Staining and Labeling
chemical_list: D000485:Allergens; D005456:Fluorescent Dyes; D009841:Oligonucleotides; D011108:Polymers; D011994:Recombinant Proteins; D007073:Immunoglobulin E; D012822:Silicon Dioxide