title: Manipulating cell adhesions with optical tweezers for study of cell-to-cell interactions.
abstract: This paper presents an approach to manipulating cell adhesions using optical tweezers for cell-to-cell interactions at single cell level. A case study of investigating the adhesions between leukemia cells and bone marrow stromal cells is reported. First, the trapping force imposed on the cell is calibrated and the viability of leukemia cells after optical trapping is tested and verified. This is for demonstrating the feasibility of the proposed optical manipulation method. Second, properties of adhesions of leukemia cells K562 on stromal cells M210B4 from mouse and HS5 from human are characterized. Based on characterization results, we classify adhesions into three categories namely tightly adherent, loosely adherent or free suspending. Finally, the adhesion abilities of K562 on M210B4 and HS5 are changed by adding heparin into culture medium, which demonstrates the specificity of the adhesion. The important contribution of this paper lies in development of a dexterous cell manipulation method to characterize cell adhesion properties, which helps create a new opportunity to investigate cell-to-cell interactions at single cell level.
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Songyu
authors.initials: S
authors.lastname: Hu
authors.forename: Xue
authors.initials: X
authors.lastname: Gou
authors.forename: Hochun
authors.initials: H
authors.lastname: Han
authors.forename: Anskar Y H
authors.initials: AY
authors.lastname: Leung
authors.forename: Dong
authors.initials: D
authors.lastname: Sun
mesh_terms: D000818:Animals; D002138:Calibration; D002448:Cell Adhesion / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D020014:K562 Cells; D051379:Mice; D052898:Optical Tweezers; D011419:Propidium / Q000378:metabolism
chemical_list: D011419:Propidium; D006493:Heparin