Vascular Smooth Muscle Cells on Polyelectrolyte Multilayers:  Hydrophobicity-Directed Adhesion and Growth

Abstract

Polyelectrolyte multilayer films were employed to support attachment of cultured rat aortic smooth muscle A7r5 cells. Like smooth muscle cells in vivo, cultured A7r5 cells are capable of converting between a nonmotile "contractile" phenotype and a motile "synthetic" phenotype. Polyelectrolyte films were designed to examine the effect of surface charge and hydrophobicity on cell adhesion, morphology, and motility. The hydrophobic nature and surface charge of different polyelectrolyte films significantly affected A7r5 cell attachment and spreading. In general, hydrophobic polyelectrolyte film surfaces, regardless of formal charge, were found to be more cytophilic than hydrophilic surfaces. On the most hydrophobic surfaces, the A7r5 cells adhered, spread, and exhibited little indication of motility, whereas on the most hydrophilic surfaces, the cells adhered poorly if at all and when present on the surface displayed characteristics of being highly motile. The two surfaces that minimized cell adhesion consisted of two varieties of a diblock copolymer containing hydrophilic poly(ethylene oxide) and a copolymer bearing a zwitterionic group AEDAPS, (3-[2-(acrylamido)-ethyldimethyl ammonio] propane sulfonate). Increasing the proportion of AEDAPS in the copolymer decreased the adhesion of cells to the surface. Cells presented with micropatterns of cytophilic and cytophobic surfaces generated by polymer-on-polymer stamping displayed a surface-dependent cytoskeletal organization and a dramatic preference for adhesion to, and spreading on, the cytophilic surface, demonstrating the utility of polyelectrolyte films in manipulating smooth muscle cell adhesion and behavior.

Multiple Functionalities of Polyelectrolyte Multilayer Films: New Biomedical Applications

“…[122,154] For PAH/PAA films, the non-adhesiveness of the films built at pH 2 and the high adhesion observed for films built at pH 6.5 were instead attributed to the ability of the former to swell. [122] Synthetic polymers were also employed by Salloum et al [155] for investigating the combined effects of increasing surface charge and hydrophobicity on vascular smooth muscle cell (SMCs) adhesion. On the most hydrophobic surfaces, the A7R75 SMCs spread and were not very motile, whereas on the most hydrophobic surfaces, these cells adhered poorly and displayed characteristics of being highly motile.…”

Nanostructured materials for applications in drug delivery and tissue engineering

“…Layer-bylayer deposition provides an alternative strategy to fine tune the surface properties of polymeric scaffolds on the nanometer scale [182][183][184]. Recent studies demonstrate that one can easily control the cell behaviors on these self-assembled multilayers by simple manipulation of the deposition process [185][186][187][188][189][190]. However, polyelectrolyte multilayer studies are limited to planner surfaces and spherical particles.…”

Polyelectrolyte Multilayers in Tissue Engineering

“…Thicker PEMs were less rigid due to a higher degree of hydration. 5,64 When SMCs were cultured on the PLL/HA multilayer, projected cell areas were observed to be *1100 mm 2 on substrates comprised of 20 bilayers, compared to 800 mm 2 for a substrate coated with 60 bilayers. 16 In another study by the same group, the adhesion of human chondrosarcoma cells increased with decreased PLL/poly (L-glutamic acid) (PLGA) PEM thickness.…”