Characterizing hydrogel imposed strain fields on brain tissue phantom for use in neural implant device coatings in presence of micromotion

Glial scar tissue forms in the brain as a response to the implant injury and hampers the effectiveness of the implant treatment. Constant relative micromotion between the mechanically mismatched neural implant and brain tissue is thought to play a key role glial scar formation. This study investigated the effects of poly(ethylene glycol) (PEG) hydrogel coatings for glass brain implant devices on strain fields imposed by those devices to brain tissue due to micromotion in the brain. PEG hydrogels were created using macromers of 2000-8000 Mw and 5-20 wt.% in solution. The moduli of the hydrogels were calculated via Hertzian analysis of force-deflection curves produced using an AFM tip as a nanoindenter. The moduli of the samples did not change significantly with change in macromer Mw, but did change with solution concentration. 20% gels had moduli of 120-180 kPa and 5-10% gels had moduli of 0-20 kPa. The strains imposed by the coated devices were found to be lower at the surface by ~30% as compared to uncoated and the strain field dropped off much more quickly.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2014

Author dc:creator

• Plaut, Maxwell Ethan

Advisor dc:contributor.advisor

• Michael Cima.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/89977

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/89977