文章基本信息

标题：Dependence of cancer cell adhesion kinetics on integrin ligand surface density measured by a high-throughput label-free resonant waveguide grating biosensor
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作者：Norbert Orgovan ; Beatrix Peter ; Szilvia Bősze 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2014
卷号：4
DOI：10.1038/srep04034
出版社：Springer Nature
摘要：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 (Δλ_max), which is assumed to be directly proportional to the maximum spread contact area ( A _max). r was found to be independent of the surface density of integrin ligands. In contrast, Δλ_max 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.