title: An amphiphilic degradable polymer/hydroxyapatite composite with enhanced handling characteristics promotes osteogenic gene expression in bone marrow stromal cells.
abstract: Electrospun polymer/hydroxyapatite (HA) composites combining biodegradability with osteoconductivity are attractive for skeletal tissue engineering applications. However, most biodegradable polymers such as poly(lactic acid) (PLA) are hydrophobic and do not blend with adequate interfacial adhesion with HA, compromising the structural homogeneity, mechanical integrity and biological performance of the composite. To overcome this challenge, we combined a hydrophilic polyethylene glycol (PEG) block with poly(d,l-lactic acid) to improve the adhesion of the degradable polymer with HA. The amphiphilic triblock copolymer PLA-PEG-PLA (PELA) improved the stability of HA-PELA suspension at 25wt.% HA content, which was readily electrospun into HA-PELA composite scaffolds with uniform fiber dimensions. HA-PELA was highly extensible (failure strain>200% vs. <40% for HA-PLA), superhydrophilic (∼0° water contact angle vs. >100° for HA-PLA), and exhibited an 8-fold storage modulus increase (unlike deterioration for HA-PLA) upon hydration, owing to the favorable interaction between HA and PEG. HA-PELA also better promoted osteochondral lineage commitment of bone marrow stromal cells in unstimulated culture and supported far more potent osteogenic gene expression upon induction than HA-PLA. We demonstrate that the chemical incorporation of PEG is an effective strategy to improve the performance of degradable polymer/HA composites for bone tissue engineering applications.
authors.affiliation: Department of Orthopedics & Physical Rehabilitation, University of Massachusetts Medical School, 55 Lake Ave North, Worcester, MA 01655, USA.
authors.forename: Artem B
authors.initials: AB
authors.lastname: Kutikov
authors.forename: Jie
authors.initials: J
authors.lastname: Song
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D018786:Bone Substitutes / Q000138:chemical synthesis*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D017886:Durapatite / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005786:Gene Expression Regulation / Q000502:physiology; D057927:Hydrophobic and Hydrophilic Interactions; D007773:Lactates / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology; D010012:Osteogenesis / Q000502:physiology*; D011092:Polyethylene Glycols / Q000737:chemistry*; D051381:Rats; D054457:Tissue Scaffolds
chemical_list: D018786:Bone Substitutes; D007773:Lactates; C058523:polyethylene oxide-polylactic acid block copolymer; D011092:Polyethylene Glycols; D017886:Durapatite
keywords: Amphiphilic polymer; Bone tissue engineering; Composite materials; Electrospinning; Hydroxyapatite