title: Label-free monitoring of antibody-antigen interactions using optical microchip biosensors.
abstract: A rapid, label-free optical biosensor system for sensitive monitoring of bio-molecular interactions in real-time is presented. SpectroSens sensor chips are based on integrated planar Bragg gratings sensitive to localised changes in refractive index. Bio-molecule recognition is imparted by functionalisation of the sensing surface with antibodies against targets of interest. In this study, antibodies against selected proteins were oriented with recombinant Protein A/G, which was covalently immobilised to the sensor chip via amine coupling to a glutaraldehyde-activated silane layer. Immunoassays for the detection of rabbit IgG and ovalbumin proteins as model antibody-antigen interaction systems were performed. Binding of complementary antigens to respective antibody-functionalised sensors manifested as changes in wavelength of light reflected from the optical sensors. Quantitative binding kinetics with detection sensitivities in the mid ng/ml range were obtained for both antigens using this planar, two-dimensional surface coating. Data presented demonstrate the suitability of SpectroSens sensors as a valuable tool in life science research and development for monitoring bio-specific interactions, protein concentration determination and antibody selection; the optical integration and analytical characteristics of these sensors suggest that they may find numerous applications in bio-pharmaceutical development and clinical diagnostics.
authors.affiliation: Stratophase Ltd., Unit 10a, The Quadrangle, Premier Way, Romsey SO51 9DL, United Kingdom. devaki.bhatta@stratophase.com
authors.forename: D
authors.initials: D
authors.lastname: Bhatta
authors.forename: E
authors.initials: E
authors.lastname: Stadden
authors.forename: E
authors.initials: E
authors.lastname: Hashem
authors.forename: I J G
authors.initials: IJ
authors.lastname: Sparrow
authors.forename: G D
authors.initials: GD
authors.lastname: Emmerson
mesh_terms: D000818:Animals; D000906:Antibodies / Q000032:analysis*; D000941:Antigens / Q000032:analysis*; D001426:Bacterial Proteins / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D006041:Goats; D040081:Protein Array Analysis / Q000379:methods*; D011817:Rabbits; D012680:Sensitivity and Specificity; D013205:Staphylococcal Protein A / Q000737:chemistry*
chemical_list: D000906:Antibodies; D000941:Antigens; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D013205:Staphylococcal Protein A