title: Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor.
abstract: A novel high-throughput label-free resonant waveguide grating (RWG) imager biosensor, the Epic® BenchTop (BT), was utilized to determine the dependence of cell spreading kinetics on the average surface density (v(RGD)) of integrin ligand RGD-motifs. v(RGD) was tuned over four orders of magnitude by co-adsorbing the biologically inactive PLL-g-PEG and the RGD-functionalized PLL-g-PEG-RGD synthetic copolymers from their mixed solutions onto the sensor surface. Using highly adherent human cervical tumor (HeLa) cells as a model system, cell adhesion kinetic data of unprecedented quality were obtained. Spreading kinetics were fitted with the logistic equation to obtain the spreading rate constant (r) and the maximum biosensor response (Δλmax), which is assumed to be directly proportional to the maximum spread contact area (Amax). r was found to be independent of the surface density of integrin ligands. In contrast, Δλmax increased with increasing RGD surface density until saturation at high densities. Interpreting the latter behavior with a simple kinetic mass action model, a 2D dissociation constant of 1753 ± 243 μm(-2) (corresponding to a 3D dissociation constant of ~30 μM) was obtained for the binding between RGD-specific integrins embedded in the cell membrane and PLL-g-PEG-RGD. All of these results were obtained completely noninvasively without using any labels.
authors: 1] Department of Biological Physics, Eötvös University, Pázmány P. stny. 1/A, H-1117 Budapest, Hungary [2] Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1120 Budapest, Hungary.
authors: Norbert
authors: N
authors: Orgovan
authors: 1] Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1120 Budapest, Hungary [2] Doctoral School of Molecular- and Nanotechnologies, Faculty of Information Technology, University of Pannonia, H-8200 Egyetem u.10, Veszprém, Hungary.
authors: Beatrix
authors: B
authors: Peter
authors: Research Group of Peptide Chemistry, Hungarian Academy of Sciences, Eötvös Loránd University, Budapest 112, POB 32, Hungary, H-1518.
authors: Szilvia
authors: S
authors: Bősze
authors: 1] Clore Laboratory, University of Buckingham, MK18 1EG, UK [2] Centre for Molecular Recognition, Collegium Basilea (Institute of Advanced Study), Hochstrasse 51, CH-4053 Basel, Switzerland.
authors: Jeremy J
authors: JJ
authors: Ramsden
authors: 1] Department of Biological Physics, Eötvös University, Pázmány P. stny. 1/A, H-1117 Budapest, Hungary [2] Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1120 Budapest, Hungary.
authors: Bálint
authors: B
authors: Szabó
authors: Hungarian Academy of Sciences, Research Centre for Natural Sciences, Institute for Technical Physics and Materials Science, Konkoly-Thege út 29-33, H-1120 Budapest, Hungary.
authors: Robert
authors: R
authors: Horvath
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D016023:Integrins / Q000378:metabolism; D011092:Polyethylene Glycols; D011107:Polylysine / Q000031:analogs & derivatives; D011108:Polymers; D013499:Surface Properties
chemical_list: D016023:Integrins; D011108:Polymers; C443714:polylysine-graft-(poly(ethylene glycol)); D011107:Polylysine; D011092:Polyethylene Glycols