title: Cell receptor and surface ligand density effects on dynamic states of adhering circulating tumor cells.
abstract: Dynamic states of cancer cells moving under shear flow in an antibody-functionalized microchannel are investigated experimentally and theoretically. The cell motion is analyzed with the aid of a simplified physical model featuring a receptor-coated rigid sphere moving above a solid surface with immobilized ligands. The motion of the sphere is described by the Langevin equation accounting for the hydrodynamic loadings, gravitational force, receptor-ligand bindings, and thermal fluctuations; the receptor-ligand bonds are modeled as linear springs. Depending on the applied shear flow rate, three dynamic states of cell motion have been identified: (i) free motion, (ii) rolling adhesion, and (iii) firm adhesion. Of particular interest is the fraction of captured circulating tumor cells, defined as the capture ratio, via specific receptor-ligand bonds. The cell capture ratio decreases with increasing shear flow rate with a characteristic rate. Based on both experimental and theoretical results, the characteristic flow rate increases monotonically with increasing either cell-receptor or surface-ligand density within certain ranges. Utilizing it as a scaling parameter, flow-rate dependent capture ratios for various cell-surface combinations collapse onto a single curve described by an exponential formula.
authors.affiliation: Department of Aerospace and Mechanical Engineering, the University of Arizona, Tucson, AZ, USA.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Zheng
authors.forename: Luthur Siu-Lun
authors.initials: LS
authors.lastname: Cheung
authors.forename: Joyce A
authors.initials: JA
authors.lastname: Schroeder
authors.forename: Linan
authors.initials: L
authors.lastname: Jiang
authors.forename: Yitshak
authors.initials: Y
authors.lastname: Zohar
mesh_terms: D000906:Antibodies / Q000378:metabolism; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D002469:Cell Separation / Q000295:instrumentation*; D006801:Humans; D008024:Ligands; D046210:Microfluidic Analytical Techniques; D009360:Neoplastic Cells, Circulating / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D000906:Antibodies; D008024:Ligands; D011956:Receptors, Cell Surface