title: Kinetics of Antibody Binding to Membranes of Living Bacteria Measured by a Photonic Crystal-Based Biosensor.
abstract: Optical biosensors based on photonic crystal surface waves (PC SWs) offer a possibility to study binding interactions with living cells, overcoming the limitation of rather small evanescent field penetration depth into a sample medium that is characteristic for typical optical biosensors. Besides this, simultaneous excitation ofs- andp-polarized surface waves with different penetration depths is realized here, permitting unambiguous separation of surface and volume contributions to the measured signal. PC-based biosensors do not require a bulk signal correction, compared to widely used surface plasmon resonance-based devices. We developed a chitosan-based protocol of PC chip functionalization for bacterial attachment and performed experiments on antibody binding to living bacteria measured in real time by the PCSW-based biosensor. Data analysis reveals specific binding and gives the value of the dissociation constant for monoclonal antibodies (IgG2b) against bacterial lipopolysaccharides equal toKD= 6.2 ± 3.4 nM. To our knowledge, this is a first demonstration of antibody-binding kinetics to living bacteria by a label-free optical biosensor.
authors.affiliation: Laboratoire de Physique de la Matière Vivante, IPHYS, École Polytechnique Fédérale de Lausanne (EPFL); Rte de la Sorge, 1015 Lausanne, Switzerland. ekaterina.rostova@epfl.ch.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Rostova
authors.affiliation: Laboratoire de Physique de la Matière Vivante, IPHYS, École Polytechnique Fédérale de Lausanne (EPFL); Rte de la Sorge, 1015 Lausanne, Switzerland. carine.benadiba@epfl.ch.
authors.forename: Carine
authors.initials: C
authors.lastname: Ben Adiba
authors.affiliation: Laboratoire de Physique de la Matière Vivante, IPHYS, École Polytechnique Fédérale de Lausanne (EPFL); Rte de la Sorge, 1015 Lausanne, Switzerland. giovanni.dietler@epfl.ch.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Dietler
authors.affiliation: Laboratoire de Physique de la Matière Vivante, IPHYS, École Polytechnique Fédérale de Lausanne (EPFL); Rte de la Sorge, 1015 Lausanne, Switzerland. serguei.sekatski@epfl.ch.
authors.forename: Sergey K
authors.initials: SK
authors.lastname: Sekatskii
mesh_terms: D000906:Antibodies; D001419:Bacteria; D015374:Biosensing Techniques; D002462:Cell Membrane; D007700:Kinetics; D017785:Photons; D011485:Protein Binding
chemical_list: D000906:Antibodies
keywords: antibody; bacteria; binding kinetics; label-free biosensor; ligand-receptor interaction; photonic crystal