title: Effects of neutral polymers on the mechanics of red blood cell adhesion onto coated glass surfaces.
abstract: BACKGROUND
  Cell-cell and cell-surface adhesion modulated by water-soluble polymers continues to be of current interest, especially since prior reports have indicated a role for depletion-mediated attractive forces.
  
  
  OBJECTIVE
  To determine the effects of concentration and molecular mass of the neutral polymer dextran (40 kDa to 28 MDa) on the adhesion of human red blood cells (RBC) to coated glass coverslips.
  
  
  METHODS
  Confocal-reflection interference contrast microscopy (C-IRM), in conjunction with phase contrast imaging, was utilized to measure the adhesion dynamics and contact mechanics of RBC during the initial stages of cell contact with several types of substrates.
  
  
  RESULTS
  Adhesion is markedly increased in the presence of dextran with a molecular mass ⩾ 70 kDa. This increased adhesiveness is attributed to reduced surface concentration of the large polymers and hence increased attractive forces due to depletion interaction. The equilibrium deformation of adhering RBC was modeled as a truncated sphere and the calculated adhesion energies were in close agreement with theoretical results.
  
  
  CONCLUSIONS
  These results clearly demonstrate that polymer depletion can promote RBC adhesion to artificial surfaces and suggest that this phenomenon may play a role in other specific and non-specific cell-cell interactions, such as rouleau formation and RBC-endothelial cell adhesion.
authors.affiliation: Division of Bioengineering, Nanyang Technological University, Jurong West, Singapore.|Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Zhengwen
authors.affiliation: Department of Physiology and Biophysics, Keck School of Medicine, Los Angeles, CA, USA.
authors.forename: Herbert J
authors.initials: HJ
authors.lastname: Meiselman
authors.affiliation: Faculty of Life Sciences, University of Applied Sciences Rhine-Waal, Kleve, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Neu
mesh_terms: D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D003911:Dextrans / Q000737:chemistry*; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism; D005898:Glass / Q000737:chemistry; D006801:Humans; D008857:Microscopy, Interference; D008970:Molecular Weight; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013499:Surface Properties
chemical_list: D003911:Dextrans; D012710:Serum Albumin, Bovine
keywords: Adhesion; depletion interaction; dextran; interference reflection microscopy; red blood cell