Synthesis and protein immobilization of poly(acrylic acid) brushes for stem cell culture

Abstract

Surface-tethered poly(acrylic acid) (PAA) brushes were prepared by surface initiated polymerization of tert-butyl acrylate from glass substrates via activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) followed by hydrolysis using methanesulfonic acid. Upon using an optimized condition, poly(tert-butyl acrylate) brushes having a graft density of approximately 0.33 chains/nm² were obtained. Carboxyl group density of the PAA brushes can be varied as a function of the chain length or molecular weight ranging from 0.7 x10⁻⁹ to 1.6 x10⁻⁹ mol/cm². It has been demonstrated that the carboxyl groups of PAA brushes are readily available for attachment of BSA and N-cadherin mimic cyclic peptide. The successive surface modification via polymer brushes formation and protein/peptide immobilization were also verified by ATR-FTIR analysis and water contact angle measurements. According to cytotoxicity test against mouse neural progenitor cell, it was found that the immobilized N-cadherin mimic cyclic peptide on PAA brushes was non toxic and provided a level of cell compatibility equivalent to that of the surface coated with laminin, a commonly used adhesive protein for stem cell culture suggesting its potential in stem cell culture applications.