title: Photochemical attachment of biomolecules onto fibre-optics for construction of a chemiluminescent immunosensor.
abstract: We report herein a simple and effective way to photochemically immobilize biomolecules onto a fibre-optic silica surface. The system is based on a photoreactive benzophenone derivative that is bound to SiO2 surfaces of the optical fibre via a silane anchor. The benzophenone derivative was 4-allyloxybenzophenone, synthesized by standard procedures that were later used to synthesize the 4-(3'-chlorodimethylsilyl) propyloxybenzophenone and 4-(3'-dichloromethylsilyl) propyloxybenzophenone by regular hydrosilation procedures. After silanization with the benzophenone derivatives, the fibres were immersed in a cholera toxin B subunit solution and illuminated with UV light (wavelength > 345 nm). As a result of the photochemical reaction, a thin layer of the antigen was covalently bound to the benzophenone-modified surface. The photochemically modified fibre-optics were then tested as immunosensors in the detection of cholera anti-toxin antibody and revealed through chemiluminescence measurements. A secondary antibody labelled with horseradish peroxidase acted as the marker for the cholera toxin antibody. A photo-electronic set-up was designed specifically to monitor the signal. The immunosensor system was shown to be both specific and sensitive. The lowest rabbit serum titre detected was 1:1 700,000.
authors.affiliation: Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653, Beer Sheva 84105, Israel.
authors.forename: Boaz
authors.initials: B
authors.lastname: Leshem
authors.forename: Gadi
authors.initials: G
authors.lastname: Sarfati
authors.forename: Andres
authors.initials: A
authors.lastname: Novoa
authors.forename: Igor
authors.initials: I
authors.lastname: Breslav
authors.forename: Robert S
authors.initials: RS
authors.lastname: Marks
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis; D000937:Antigen-Antibody Reactions; D000941:Antigens / Q000737:chemistry; D001577:Benzophenones / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002772:Cholera Toxin / Q000737:chemistry*; D005336:Fiber Optic Technology; D007118:Immunoassay; D008163:Luminescent Measurements; D008958:Models, Molecular; D015394:Molecular Structure; D010777:Photochemistry; D011485:Protein Binding; D011817:Rabbits; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000906:Antibodies; D000941:Antigens; D001577:Benzophenones; D012822:Silicon Dioxide; D002772:Cholera Toxin