Coatings from Polyelectrolytes: Tuning Surface Properties for Controlled Cell Fate

摘要

Controlling the fate of cells via the mechanical properties of their cultural substrates provides an important tool for the improvement of biomedical devices. Thin films of polyelectrolyte multilayer (PEMU) have been used as substrates for cell culture applications due to their biocompatibility, and the ability to coat any surface and to controllably tune the surface properties.~(1-3) We were able to synthesize poly(acrylic acid) grafted with a photosensitive benzophenone molecule (PAABp). PEMU were then prepared by the alternating deposition of poly(allylamine hydrochloride) (PAH) that served as the polycation and PAABp as the polyanion on a negatively charged silicon substrate. The resulting film was photocrosslinked under UV irradiation. The apparent modulus of the film, measured using atomic force microscopy, increased with increasing irradiation times over a wide range. Photocrosslinking provided control over the regions of crosslinking. Thus, we were able to prepare a PEMU film with a gradient in elasticity or stiffness. A7r5 cells (rat aortic smooth muscle cells), known to transform from the synthetic (motile) phenotype to contractile (static) phenotype on stiffer substrates,~1 were plated on the gradient and they showed higher preference for the rigid part of the gradient, expressing the contractile phenotype.