Controlled adhesion of human lymphocytes on electrically charged polymer surface having phosphorylcholine moiety

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Abstract
The human lymphocytes were interacted with polymer surfaces whose surface potential was controlled by the formation of a polyion complex (PIC) having a phosphorylcholine moiety. 3-(Methacryloyloxypropyl)-trimethyl ammonium iodide as the cationic unit or potassium 3-methacryloyloxypropyl sulfonate as the anionic unit was copolymerized with 2-methacryloyloxyethylphosphorylcholine (MPC) and n-butyl methacrylate. PIC was made at the solid-liquid interface, that is, an aqueous solution containing an anionic polymer with different concentrations was contacted with a cationic polymer coated polymer membrane. The formation process of PIC was followed using a quartz crystal microbalance, and the PIC surfaces were analyzed by ζ potential and X-ray photoelectron spectroscopy. The surface potential on the PIC was controllable from +20 to -16 mV, which increased in the amount of adsorbed anionic copolymer as the ζ potential decreased toward the negative charge. The PIC surface in contact with human lymphocyte for 5 h was observed using ascanning electron microscopy and the density of the adherent human lymphocyte was determined by the lactate dehydrogenase method. The lymphocyte adhesion on the surface was gradually reduced with an increase in the negative value of the ζ potential. The morphological change in the adherent lymphocytes was not observed on the polymer surfaces with MPC units.The adherent lymphocytes were not activated on the PIC surface. The lymphocyte adhesion with reduced activation could be controlled by changing the surface potential on the polymer with the MPC unit.