Nonviral Gene Delivery of Growth and Differentiation Factor 5 to Human Mesenchymal Stem Cells Injected into a 3D Bovine Intervertebral Disc Organ Culture System. - Bucher, Christian; Gazdhar, Amiq; Benneker, Lorin M.; Geiser, Thomas; Gantenbein-Ritter, Benjamin (Stem Cells International, 2013)