title: In vitro degradation of porous poly(propylene fumarate)/poly(DL-lactic-co-glycolic acid) composite scaffolds.
abstract: This study investigated the in vitro degradation of porous poly(propylene fumarate) (PPF-based) composites incorporating microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) during a 26-week period in pH 7.4 phosphate-buffered saline at 37 degrees C. Using a fractional factorial design, four formulations of composite scaffolds were fabricated with varying PEG content of the microparticles, microparticle mass fraction of the composite material, and initial leachable porogen content of the scaffold formulations. PPF scaffolds without microparticles were fabricated with varying leachable porogen content for use as controls. The effects of including PLGA/PEG microparticles in PPF scaffolds and the influence of alterations in the composite formulation on scaffold mass, geometry, water absorption, mechanical properties and porosity were examined for cylindrical specimens with lengths of 13 mm and diameters of 6.5 mm. The composite scaffold composition affected the extent of loss of polymer mass, scaffold length, and diameter, with the greatest loss of polymer mass equal to 15+/-5% over 26 weeks. No formulation, however, exhibited any variation in compressive modulus or peak compressive strength over time. Additionally, sample porosity, as determined by both mercury porosimetry and micro-computed tomography did not change during the period of this study. These results demonstrate that microparticle carriers can be incorporated into PPF scaffolds for localized delivery of bioactive molecules without altering scaffold mechanical or structural properties up to 26 weeks in vitro.
authors.affiliation: Department of Bioengineering, Rice University, P.O. Box 1892-MS 142, Houston, TX 77251-1892, USA.
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Hedberg
authors.forename: Charles K
authors.initials: CK
authors.lastname: Shih
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Lemoine
authors.forename: Mark D
authors.initials: MD
authors.lastname: Timmer
authors.forename: Michael A K
authors.initials: MA
authors.lastname: Liebschner
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D005650:Fumarates / Q000737:chemistry*; D006016:Glycolates / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000737:chemistry; D008422:Materials Testing; D008628:Mercury / Q000737:chemistry; D008833:Microcirculation; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011126:Polypropylenes / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D023822:Tissue Engineering; D014057:Tomography, X-Ray Computed; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D005650:Fumarates; D006016:Glycolates; D011108:Polymers; D011126:Polypropylenes; C097850:poly(propylene fumarate); D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D008628:Mercury