Date of Award
Master of Science
Metallurgical and Materials Engineering
Ryan B. Wicker
Lawrence E. Murr
One of the challenges in tissue engineering is to have spatial and temporal control over the biological elements within a scaffold used to guide regeneration for example of transected nerves. Some of the physical and chemical characteristics to regulate include incorporation of bioactive domains and release of chemical signals. This study presents the use of stereolithography (SL) to incorporate localized domains for cell adhesion in addition to include releasable nerve growth factor (NGF) in the process of building poly(ethylene glycol)diacrylate (PEGda) hydrogel scaffolds. Besides providing sites for cell attachment, an ideal nerve guidance conduit (NGC) should be able to release growth factors to promote the axonsÂ´ growth. NGF is a neurotrophin known to enhance survival, growth and differentiation of nerve cells. This protein was either encapsulated or conjugated to the polymer of varying concentrations of two molecular weights, PEGda 3.4 and 6 kDa. PEG hydrogels released the neurotrphin into RPMI-1640 cell culture medium. An NGF release profile was determined by enzyme-linked immunosorbent assay (ELISA). Results showed that protein release increased with increasing molecular weight of the matrixÂ´s mesh and diminished with decreased concentration within the same PEGÂ´s mw. The total amount of trapped NGF diffused after one week from PEG 20 wt% 3.4 kDa, 30 wt% 3.4 kDa and 10 %(w/v) 6 kDa was 93Â±1.9, 46Â±2ng and 292.23Â±6.5ng, respectively. Gels with the conjugated protein released 254.6Â±21.1 from 6kDa PEG matrix and 19.2Â±0.4 from 3.4kDa PEG gels after 15 days. The hydrogelsÂ´ supernatants were added to pheochromocytoma (PC-12) cells to demonstrate bioactivity by observing neurite extension of in response to NFG. Ultimately, SL shows as a promising tool for producing bioactive synthetic PEG guides for peripheral nerve regeneration.
Received from ProQuest
Zuverza, Nubia, "Exploring Poly(ethylene Glycol) As A Suitable Material For Peripheral Nerve Regeneration Scaffolds Manufactured By Stereolithography" (2009). Open Access Theses & Dissertations. 391.