Functionalization of polylactide (PLA) surface using heterobifunctional PEG/PLA block copolymers for the control of cell behavior at surfaces

This paper deals with novel approaches established by our group for the construction of a functionalized poly(ethylene glycol) (PEG) layer, PEG-brushed layer possessing a reactive group at the free end of tethered PEG chain, on substrates. An AB-type block copolymer composed of /spl alpha/-acetal-poly(ethylene glycol) (PEG) as the hydrophilic segment and polylactide (PLA) as the hydrophobic segment was synthesized, and utilized to construct the functionalized PEG layer on the biodegradable polylactide surface by simple coating. In this way, a PEG-brushed layer with a terminal aldehyde group was readily prepared which may have both non-fouling and ligand-binding properties. Non-fouling property of PEG strands eliminates nonspecific and uncontrolled interactions of the surface with biological components, including cells and proteins, while presentation of tethered ligands attached to the chain end of PEG brush allows cell behavior at the surface to be modulated in a specific manner via receptor-mediated signaling. Based on the characterization of these PEGylated surfaces from a physicochemical (contact angle, atomic force microscopy, electron spin resonance) as well as biological (protein adsorption/cell adhesion) point of view, our strategy to construct a functionalized PEG layer was confirmed. Active functional groups were present at the tethered PEG-chain end, these materials will provide new insights into controlling cell behavior at surfaces for tissue engineering and biomedical applications.