In situ nanomechanical characterization of the early stages of swelling and degradation of a biodegradable polymer.
The interactions of a biodegradable scaffold with cells or living tissues depend on the time-evolution of the nanoscale properties of the scaffold. We present an in situ quantitative study on the early-stage swelling and degradation of poly(lactic-co-glycolic acid) (PLGA). A novel metrology scheme based on force microscopy measurements of the patterns of PLGA nanostructures is developed to characterize the evolution of topography, volume and nanomechanical properties. The volume and nanoscale roughness show an oscillating behaviour during the first eight days of immersion; at a later stage, we observe a continuous decrease of the volume. The effective Young's modulus exhibits a monotonic decrease from an initial value of about 2.4 GPa down to 9 MPa at day 14. The oscillating behaviour of the volume before the onset of full degradation is explained by a coupled diffusion-swelling mechanism. The appearance of a second maximum in the volume evolution results from the competition between swelling and degradation.
Instituto de Ciencia de Materiales de Madrid, CSIC, c/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain. r.garcia@csic.es.
A C
AC
Dumitru
F M
FM
Espinosa
R
R
Garcia
G
G
Foschi
S
S
Tortorella
F
F
Valle
M
M
Dallavalle
F
F
Zerbetto
F
F
Biscarini
D020341:Absorbable Implants; D065966:Absorption, Physicochemical; D001672:Biocompatible Materials / Q000737:chemistry*; D063566:Biodegradable Plastics / Q000737:chemistry*; D004058:Diffusion; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006244:Hardness; D007700:Kinetics; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D008956:Models, Chemical; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012965:Sodium Chloride / Q000737:chemistry*; D013499:Surface Properties; D054457:Tissue Scaffolds; D014783:Viscosity
D001672:Biocompatible Materials; D063566:Biodegradable Plastics; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D012965:Sodium Chloride