Synthesis of macromolecular mimics of small leucine-rich proteoglycans with a poly(ethylene glycol) core and chondroitin sulphate bristles.

Small leucine-rich proteoglycans (SLRPs) are a class of molecules prevalent in almost all tissues types and are thought to be responsible for collagen organization and macro-scale biological properties. However, when they are dysfunctional or degraded, severe pathological phenotypes are observed. Here we investigate macromolecular mimics to SLRPs using poly(ethylene glycol) (PEG) as a core (replacing the protein core of natural SLRPs) and chondroitin sulphate (CS) bristle(s) in an end-on attachment (via epoxide-amine reactions), mimicking the physical structure of the natural SLRPs. Poly(ethylene glycol)-diglycidyl ether (PEG-DEG) and ethylene glycol-diglycidyl ether (EG-DGE) monomers were used to incorporate CS bristles into a macromolecule that closely mimics the SLRP biglycan structure in a grafting-to strategy. The kinetics of these reactions was studied along with the specific viscosity and cytocompatibility of resulting CS macromolecules. Structures were found to incorporate two CS chains (similar to biglycan) on average and exhibited cytocompatibility equivalent to or better than CS-only controls.