Generic, anthracene-based hydrogel crosslinkers for photo-controllable drug delivery

Abstract

Light-responsive polymers with controllable, reversible crosslink mechanisms have the potential to create unique biomaterials with stimulus-controlled swelling, degradation and diffusion properties useful in tissue engineering and drug delivery applications. Generic photodimerizing polyethylene glycol-anthracene macromolecules that may be grafted to various polymers to effectively control their crosslinking via a photodimerization mechanism have been developed. These generic crosslinkers were shown to effectively introduce photoresponsive properties into hyaluronate and alginate as model hydrophilic polymers. In vitro testing using human corneal epithelial cells was used to demonstrate cytocompatibility of the resulting photogels. The effective crosslinking density of the photogels could be increased resulting in a decrease in the release rate of small and large molecules from the photogels following exposure to 365nm light. This tuneable crosslinking has the potential to manipulate the delivery rates of therapeutics resulting in control over treatment profiles and may lend itself to various applications, which may benefit from light induced changes in crosslinking. Photoreversible, dimerizable polyethylene glycol-anthracene (PEG-anthracene) macromolecules were designed and synthesized as generic, graftable photocrosslinkers that may be bound to different polymers. When bound to alginate and hyaluronan, PEG-anthracene introduces photoinduced crosslinking via dimerization. Preliminary tests demonstrate cytocompatibility and light-controlled drug delivery. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.