A Hydrogel-Based Nerve Regeneration Conduit with Sub-Micrometer Feature Control

We are exploring a novel two-photon lithography technique for creating nerve guidance channels in PEGylated protein hydrogels for functional nerve regeneration. We have developed a two-photon lithography system for photoprinting of geometric landscapes at sub-micrometer spatial resolution. The photoprinting is accomplished in a light sensitive biocompatible precursor solution containing a biological backbone that is coupled to a synthetic polymer cross-linker. A non-toxic light-activated reaction is used to polymerize the precursor into the hydrogel matrix in the presence of cells and tissues. We show how PEGylated protein hydrogels made from fibrinogen and collagen are able to encourage outgrowth of neuronal and non-neuronal cells from explants of dorsal root ganglion (DRG) into the hydrogel matrix. In preliminary data, DRG cells are seen migrating out from the DRG and into channels inscribed into the hydrogel matrix. We aim to demonstrate the importance of three-dimensional (3D) spatial geometric resolution of the lithographic system in guiding nerve cells towards functional nerve regeneration.