title: Aligned PLGA/HA nanofibrous nanocomposite scaffolds for bone tissue engineering.
abstract: Aligned nanofibrous scaffolds based on poly(d,l-lactide-co-glycolide) (PLGA) and nano-hydroxyapatite (nano-HA) were synthesized by electrospinning for bone tissue engineering. Morphological characterization using scanning electron microscopy showed that the addition of different amounts of nano-HA (1, 5, 10 and 20wt.%) increased the average fiber diameter from 300nm (neat PLGA) to 700nm (20% nano-HA). At higher concentrations (>or=10%), agglomeration of HA was observed and this had a marked effect at 20% concentration whereby the presence of nano-HA resulted in fiber breaking. Thermal characterization showed that the fast processing of electrospinning locked in the amorphous character of PLGA; this resulted in a decrease in the glass transition temperature of the scaffolds. Furthermore, an increase in the glass transition temperature was observed with increasing nano-HA concentration. The dynamic mechanical behavior of the scaffolds reflected the morphological observation, whereby nano-HA acted as reinforcements at lower concentrations (1% and 5%) but acted as defects at higher concentrations (10% and 20%). The storage modulus value of the scaffolds increased from 441MPa for neat PLGA to 724MPa for 5% nano-HA; however, further increasing the concentration leads to a decrease in storage modulus, to 371MPa for 20% nano-HA. Degradation characteristics showed that hydrophilic nano-HA influenced phosphate-buffered saline uptake and mass loss. The mechanical behavior showed a sinusoidal trend with a slight decrease in modulus by week 1 due to the plasticizing effect of the medium followed by an increase due to shrinkage, and a subsequent drop by week 6 due to degradation.
authors.affiliation: Department of Materials Science and Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Moncy V
authors.initials: MV
authors.lastname: Jose
authors.forename: Vinoy
authors.initials: V
authors.lastname: Thomas
authors.forename: Kalonda T
authors.initials: KT
authors.lastname: Johnson
authors.forename: Derrick R
authors.initials: DR
authors.lastname: Dean
authors.forename: Elijah
authors.initials: E
authors.lastname: Nyairo
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning / Q000379:methods; D017886:Durapatite / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D019344:Lactic Acid / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D016062:Porosity; D011312:Pressure; D013055:Spectrophotometry, Infrared / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes; D010710:Phosphates; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D017886:Durapatite