A photolabile hydrogel for guided three-dimensional cell growth and migration.

Tissue engineering aims to replace, repair or regenerate tissue/organ function, by delivering signalling molecules and cells on a three-dimensional (3D) biomaterials scaffold that supports cell infiltration and tissue organization. To control cell behaviour and ultimately induce structural and functional tissue formation on surfaces, planar substrates have been patterned with adhesion signals that mimic the spatial cues to guide cell attachment and function. The objective of this study is to create biochemical channels in 3D hydrogel matrices for guided axonal growth. An agarose hydrogel modified with a cysteine compound containing a sulphydryl protecting group provides a photolabile substrate that can be patterned with biochemical cues. In this transparent hydrogel we immobilized the adhesive fibronectin peptide fragment, glycine-arginine-glycine-aspartic acid-serine (GRGDS), in selected volumes of the matrix using a focused laser. We verified in vitro the guidance effects of GRGDS oligopeptide-modified channels on the 3D cell migration and neurite outgrowth. This method for immobilizing biomolecules in 3D matrices can generally be applied to any optically clear hydrogel, offering a solution to construct scaffolds with programmed spatial features for tissue engineering applications.