title: Plasma functionalization procedure for antibody immobilization for SU-8 based sensor.
abstract: In this paper, we report the study on a new protocol for the immobilization process of antigen/antibody assay on SU-8 layers by oxygen plasma treatment. Plasma treatments, at different plasma powers and for different duration times, are performed and their effects on immobilization efficiency are studied. The chemical properties and the surface morphology of SU-8 before and after the functionalization and immobilization of (IgG) are then verified by Raman spectroscopy and atomic force microscopy (AFM). An increase of the surface roughness of SU-8 layers is observed after the oxygen plasma treatment and an intensity variation of functional groups is also evidenced. To demonstrate the validity of the process the distribution of IgG immobilized on SU-8 surfaces is detected by fluorescence microscopy measurement after incubation with fluorescein isothiocyanate (FITC)-tagged anti-human IgG. An increase of the amount of the adsorbed protein of about 20% and a good repeatability on antigen/antibody distribution on the surface are detected for IgG on plasma treated substrates. Finally, label free measurements are performed by SU-8 optical ring resonators reaching detection limits of 0.86ngcm(-2). The proposed approach offers a smart protocol for IgG immobilization on SU-8 substrate that can be easily extended to different antigen/antibody assay and polymeric materials for the realization of high performance immunosensors.
authors.affiliation: Institute for Electromagnetic Monitoring of the Environment (IREA), National Research Council (CNR), Naples, Italy. Electronic address: grimaldi.a@irea.cnr.it.
authors.forename: Immacolata Angelica
authors.initials: IA
authors.lastname: Grimaldi
authors.affiliation: Institute for Electromagnetic Monitoring of the Environment (IREA), National Research Council (CNR), Naples, Italy.
authors.forename: Genni
authors.initials: G
authors.lastname: Testa
authors.affiliation: Institute for Electromagnetic Monitoring of the Environment (IREA), National Research Council (CNR), Naples, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Persichetti
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Portici Research Center, P.le Enrico Fermi 1, Portici, Naples, 80055 Italy.
authors.forename: Fausta
authors.initials: F
authors.lastname: Loffredo
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Portici Research Center, P.le Enrico Fermi 1, Portici, Naples, 80055 Italy.
authors.forename: Fulvia
authors.initials: F
authors.lastname: Villani
authors.affiliation: Institute for Electromagnetic Monitoring of the Environment (IREA), National Research Council (CNR), Naples, Italy.
authors.forename: Romeo
authors.initials: R
authors.lastname: Bernini
mesh_terms: D000327:Adsorption; D000906:Antibodies / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D004852:Epoxy Compounds / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology*; D010100:Oxygen / Q000737:chemistry; D058626:Plasma Gases / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D000906:Antibodies; D004852:Epoxy Compounds; D007074:Immunoglobulin G; D058626:Plasma Gases; D011108:Polymers; C520895:SU-8 compound; D010100:Oxygen
keywords: Biosensing; Immunoglobulin G; Microring resonator; Optical biosensor; Surface immobilization