Manufacture of porous biodegradable polymer conduits by an extrusion process for guided tissue regeneration

Markus S. Widmer, Puneet K. Gupta, Lichun Lu, Rudolf K. Meszlenyi, Gregory R.D. Evans, Keith Brandt, Tom Savel, Ali Gurlek, Charles W. Patrick, Antonios G. Mikos

Research output: Contribution to journalArticlepeer-review

320 Scopus citations


We 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.

Original languageEnglish (US)
Pages (from-to)1945-1955
Number of pages11
Issue number21
StatePublished - Nov 1998


  • Biodegradable polymer;
  • Conduit
  • Extrusion
  • Guided tissue regeneration
  • Poly(DL-lactic-co-glycolic acid)
  • Poly(L-lactic acid)
  • Polymer processing
  • Scaffold
  • Tissue engineering

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials


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