title: Nanomechanical properties of poly(lactic-co-glycolic) acid film during degradation.
abstract: Despite the potential applications of poly(lactic-co-glycolic) acid (PLGA) coatings in medical devices, the mechanical properties of this material during degradation are poorly understood. In the present work, the nanomechanical properties and degradation of PLGA film were investigated. Hydrolysis of solvent-cast PLGA film was studied in buffer solution at 37 °C. The mass loss, water uptake, molecular weight, crystallinity and surface morphology of the film were tracked during degradation over 20 days. Characterization of the surface hardness and Young's modulus was performed using the nanoindentation technique for different indentation loads. The initially amorphous films were found to remain amorphous during degradation. The molecular weight of the film decreased quickly during the initial days of degradation. Diffusion of water into the film resulted in a reduction in surface hardness during the first few days, followed by an increase that was due to the surface roughness. There was a significant delay between the decrease in the mechanical properties of the film and the decrease in the molecular weight. A sudden decline in mechanical properties indicated that significant bulk degradation had occurred.
authors.affiliation: Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Ireland. Electronic address: r.neghabatshirazi1@nuigalway.ie.
authors.forename: Reyhaneh Neghabat
authors.initials: RN
authors.lastname: Shirazi
authors.affiliation: School of Chemistry, National University of Ireland Galway, Ireland.
authors.forename: Fawaz
authors.initials: F
authors.lastname: Aldabbagh
authors.affiliation: School of Chemistry, National University of Ireland Galway, Ireland.
authors.forename: Andrea
authors.initials: A
authors.lastname: Erxleben
authors.affiliation: School of Chemistry, National University of Ireland Galway, Ireland; National Centre for Biomedical Engineering Science (NCBES), National University of Ireland Galway, Ireland.
authors.forename: Yury
authors.initials: Y
authors.lastname: Rochev
authors.affiliation: Biomechanics Research Centre (BMEC), Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Ireland.
authors.forename: Peter
authors.initials: P
authors.lastname: McHugh
mesh_terms: D002850:Chromatography, Gel; D055119:Elastic Modulus; D006244:Hardness; D019344:Lactic Acid / Q000737:chemistry*; D055595:Mechanical Phenomena; D008970:Molecular Weight; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Degradation; Nanoindentation; Poly(lactic-co-glycolic) acid; Solvent-cast film