Date(s) - 01/08/2018
Hydrogels are an ideal material class in developing neural engineering approaches. The typical mild reaction conditions, manipulable material properties, and long-term biocompatibility of many of these hydrogels, especially alginate, evince strong candidacy for neural application. The material properties and in vivo stability of hydrogels can be tuned to match the surrounding meningeal or neural tissues and support tissue growth in a variety of geometries.
Neurosurgical approaches involving implantation of penetrating electrode arrays require unique approaches to seal the supportive meningeal tissues and the device without suture or harsh glues. An alginate-based dura mater patch was developed for this exact purpose. The material properties were tuned to match brain tissue and the biocompatibility and sealing capabilities were evaluated. The alginate dura mater patch resulted in a watertight seal around both a dural defect and an implanted microelectrode within a dural defect that supported cortical recordings while allowing for tissue regrowth without significant inflammation or scaring.
Regenerative peripheral-nerve interfaces are a novel method for interfacing the peripheral nervous system. Tissue engineered electronic neural interface (TEENI) devices have the potential to isolate and transduce both afferent (sensory) and efferent (motor) neural signals to produce fine control of advanced prosthetics. A novel TEENI comprised of microfabricated polyimide electrode threads supported by a hydrogel scaffold comprised of methacrylated hyaluronic acid, collagen I, and laminin was developed to enable intimate contact with regenerating axons. This unique electrode and hydrogel device has been successfully integrated into the regenerated sciatic nerve in the rat model and supported chronic implantation of the TEENI device with recordings from the regenerated peripheral nervous system.
Dr. Elizabeth Nunamaker received the BSE degree in Bioengineering from Arizona State University in 2000, the MS degree in Biomedical engineering in 2002 from Northwestern University, the PhD degree in Biomedical engineering in 2006 from University of Michigan, and the DVM degree from Purdue University in 2010. She became a Diplomate in the American College of Laboratory Animal Medicine in 2015.
From 2003 to 2006 Nunamaker was a research assistant in the Department of Biomedical Engineering, University of Michigan, where her work focused on the development of alginate for a variety of neurosurgical applications and understanding the device-tissue interface. From 2006-2007 she was a Post-Doctoral Fellow in the Center for Paralysis Research in the School of Veterinary Medicine at Purdue University, where her work focused on directed axonal growth for applications in spinal cord injuries. From 2010-2013 she was a Post-Doctoral Fellow in the Biologic Resources Laboratory at the University of Illinois at Chicago and Abbvie, Inc., where she developed as a laboratory animal veterinarian and focused her research on analgesia and anesthesia and humane endpoints for a variety of animal models.
Nunamaker is currently a clinical assistant professor with Animal Care Services at the University of Florida. Her research interests include hydrogel applications to support the neural device-tissue interfaces, animal model development and refinement, and laboratory animal analgesia.