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Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regenerationWe have fabricated porous, biodegradable tubular conduits for guided tissue regeneration using a combined solvent casting and extrusion technique. The biodegradable polymers used in this study were poly(DL-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). A polymer/salt composite was first prepared by a solvent casting process. After drying, the composite was extruded to form a tubular construct. The salt particles in the construct were then leached out leaving a conduit with an open-pore structure. PLGA was studied as a model polymer to analyze the effects of salt weight fraction, salt particle size, and processing temperature on porosity and pore size of the extruded conduits. The porosity and pore size were found to increase with increasing salt weight fraction. Increasing the salt particle size increased the pore diameter but did not affect the porosity. High extrusion temperatures decreased the pore diameter without altering the porosity. Greater decrease in molecular weight was observed for conduits manufactured at higher temperatures. The mechanical properties of both PLGA and PLLA conduits were tested after degradation in vitro for up to 8 weeks. The modulus and failure strength of PLLA conduits were approximately 10 times higher than those of PLGA conduits. Failure strain was similar for both conduits. After degradation for 8 weeks, the molecular weights of the PLGA and PLLA conduits decreased to 38% and 43% of the initial values, respectively. However, both conduits maintained their shape and did not collapse. The PLGA also remained amorphous throughout the time course, while the crystallinity of PLLA increased from 5.2% to 11.5%. The potential of seeding the conduits with cells for transplantation or with biodegradable polymer microparticles for drug delivery was also tested with dyed microspheres. These porous tubular structures hold great promise for the regeneration of tissues which require tubular scaffolds such as peripheral nerve, long bone, intestine, or blood vessel.
Document ID
20040142131
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Widmer, M. S.
(Department of Chemical Engineering and Institute of Biosciences and Bioengineering, Rice University Houston, TX 77251-1892, United States)
Gupta, P. K.
Lu, L.
Meszlenyi, R. K.
Evans, G. R.
Brandt, K.
Savel, T.
Gurlek, A.
Patrick, C. W. Jr
Mikos, A. G.
McIntire, L. V.
Date Acquired
August 22, 2013
Publication Date
November 1, 1998
Publication Information
Publication: Biomaterials
Volume: 19
Issue: 21
ISSN: 0142-9612
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: R29-AR42639
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cell Biology
Non-NASA Center

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