Into the groove: instructive silk-polypyrrole films with topographical guidance cues direct DRG neurite outgrowth. - Hardy JG; Khaing ZZ; Xin S; Tien LW; Ghezzi CE; Mouser DJ; Sukhavasi RC; Preda RC; Gil ES; Kaplan DL; Schmidt CE (Journal of biomaterials science. Polymer edition, 2015)