Daniel McKinnon demonstrated the 3D culture of motor neurons in engineered PEG hydrogels that enabled good viability and robust axon extention. He further demonstrated the importance of ECM-mimic peptides to the viability of dissociated cells and the role of hydrogel modulus and crosslinker in axon extension.
http://pubs.rsc.org/en/content/articlelanding/2013/bm/c3bm00166k
D.D. McKinnon, A.M Kloxin, and K.S. Anseth, "Synthetic hydrogel platform for three-dimensional culture of embryonic stem cell-derived motor neurons," Biomaterials Science (2013).