Combating neural degeneration from injury or disease is extremely difficult in the brain and spinal cord, i.e. central nervous system (CNS). Unlike the peripheral nerves, CNS neurons are bombarded by physical and chemical restrictions that prevent proper healing and restoration of function. The CNS is vital to bodily function, and loss of any part of it can severely and permanently alter a person's quality of life. Tissue engineering could offer much needed solutions to regenerate or replace damaged CNS tissue. This review will discuss current CNS tissue engineering approaches integrating scaffolds, cells and stimulation techniques. Hydrogels are commonly used CNS tissue engineering scaffolds to stimulate and enhance regeneration, but fiber meshes and other porous structures show specific utility depending on application. CNS relevant cell sources have focused on implantation of exogenous cells or stimulation of endogenous populations. Somatic cells of the CNS are rarely utilized for tissue engineering; however, glial cells of the peripheral nervous system (PNS) may be used to myelinate and protect spinal cord damage. Pluripotent and multipotent stem cells offer alternative cell sources due to continuing advancements in identification and differentiation of these cells. Finally, physical, chemical, and electrical guidance cues are extremely important to neural cells, serving important roles in development and adulthood. These guidance cues are being integrated into tissue engineering approaches. Of particular interest is the inclusion of cues to guide stem cells to differentiate into CNS cell types, as well to guide neuron targeting. This review should provide the reader with a broad understanding of CNS tissue engineering challenges and tactics, with the goal of fostering the future development of biologically inspired designs. Table of Contents: Introduction / Anatomy of the CNS and Progression of Neurological Damage / Biomaterials for Scaffold Preparation / Cell Sources for CNS TE / Stimulation and Guidance / Concluding Remarks

Autorentext

Ashley E. Wilkinson is currently pursuing her PhD in Chemical and Biomolecular Engineering at the University of Akron (Akron, Ohio). She received her Bachelor of Science in Biomedical Engineering in 2010 from the University of Akron with a specialization in drug delivery and tissue engineering. During her undergraduate studies, Ashley participated in cooperative education at DePuy Orthopaedics as a product development engineer. Her current research interests include neuroregenerative strategies in the brain and spinal cord, specifically stem cell differentiation via specific chemical and mechanical stimulation. Nic D.Leipzig is the Iredell Chair Assistant Professor in Chemical and Biomolecular Engineering at the University of Akron (Akron, OH). He received a Bachelor of Engineering in Chemical Engineering from McGill University (Montreal, Quebec) in 2001 and a PhD in Bioengineering from Rice University (Houston, Texas) in 2006. During his PhD he studied the biomechanics of single chondrocytes, or cartilage cells, explored how growth factors change both the cytoskeleton and the material properties of chondrocytes,developed new methods for measuring gene expression in single cells and utilized these techniques to be the first to successfully demonstrate gene expression changes by mechanotransduction in single chondrocytes. He was a postdoctoral fellow at the University of Toronto (Toronto, Ontario) in the department of Chemical Engineering and Applied Chemistry from 2006 to 2009, where he developed hydrogel systems to enable precise control of the cell microenvironment, or niche, in order to guide the differentiation of adult stem cells. He has also revealed that substrate stiffness can influence neural stem cell proliferation and differentiation and demonstrated the advantages of covalently attaching growth factors for precisely guiding stem cell differentiation. Dr. Leipzig's current research is pioneering approaches for tissue engineering of the central nervous system utilizing engineered biomaterials, incorporating niche level stimuli and new stem cell sources. Aleesha M. McCormick obtained her Bachelor of Science at Kent State University (Kent, Ohio) in Integrated Science Education and taught high school chemistry and physics for two years. She is currently pursuing a PhD at the University of Akron (Akron, OH) in Chemical and Biomolecular Engineering. Her research area focuses on recombinant protein analysis and production for utilization in axon guidance and neural regenerative applications as well as examining potential cell sourcesfor neuronal differentiation.

Inhalt
Introduction.- Anatomy of the CNS and Progression of Neurological Damage.- Biomaterials for Scaffold Preparation.- Cell Sources for CNS TE.- Stimulation and Guidance.- Concluding Remarks.