title: Design, fabrication, and characterization of a composite scaffold for bone tissue engineering.
abstract: Poly(lactide-co-glycolide) (PLGA) scaffolds have been successfully used in bone tissue engineering, with or without hydroxyapatite (HA) and with a macroporosity given either by simple PLGA sphere packaging and/or by leaching out NaCl. The objective of this work was the optimization of the design parameters for bone tissue engineering scaffolds made by sintering microspheres of PLGA, HA nanocrystals for matrix reinforcement and osteoconduction, and salt crystals for macroporosity and control of matrix pore size. Microsphere fabrication by a single-emulsion and solvent evaporation technique was first optimized to obtain a high yield of PLGA microspheres with a diameter between 80 and 300 microm. The influence of the sintering process and matrix composition on the scaffold structure was then evaluated morphologically and mechanically. Three scaffold types were tested for biocompatibility by culturing with human fibroblasts for up to 14 days. The most important parameters to obtain microspheres with the selected diameter range were the viscosity ratio of the dispersed phase to the continuous phase and the relative volume fraction of the 2 phases. The Young's modulus and the ultimate strength of the sintered matrices ranged between 168-265 MPa and 6-17 MPa, respectively, within the range for trabecular bone. Biocompatibility was demonstrated by fibroblast adhesion, proliferation, and spreading throughout the matrix. This work builds upon previous work of the PLGA/HA sintering technique to give design criteria for fabricating a bone tissue engineered matrix with optimized morphological, functional, and biological properties to fit the requirements of bone replacements.
authors.affiliation: LaBS, Department of Structural Engineering, Politecnico di Milano, Milan and IRCCS Istituto Ortopedico Galeazzi, Milan, Italy. federica.boschetti@polimi.it
authors.forename: F
authors.initials: F
authors.lastname: Boschetti
authors.forename: A A
authors.initials: AA
authors.lastname: Tomei
authors.forename: S
authors.initials: S
authors.lastname: Turri
authors.forename: M A
authors.initials: MA
authors.lastname: Swartz
authors.forename: M
authors.initials: M
authors.lastname: Levi
mesh_terms: D001861:Bone Regeneration / Q000187:drug effects; D018786:Bone Substitutes / Q000737:chemistry* / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry* / Q000494:pharmacology; D055119:Elastic Modulus; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D019344:Lactic Acid / Q000737:chemistry* / Q000494:pharmacology; D008422:Materials Testing; D008863:Microspheres; D011100:Polyglycolic Acid / Q000737:chemistry* / Q000494:pharmacology; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D012965:Sodium Chloride / Q000737:chemistry; D013997:Time Factors; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*; D014783:Viscosity
chemical_list: D018786:Bone Substitutes; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D012965:Sodium Chloride; D017886:Durapatite