title: In situ characterization of the degradation of PLGA microspheres in hyaluronic acid hydrogels by optical coherence tomography.
abstract: The polymeric implant material poly(lactide-co-glycolide) (PLGA) degrades by a process of bulk degradation, which allows it to be used for the controlled release of therapeutic molecules from implants and microspheres. The temporal characterization of PLGA microsphere degradation has been limited by the need to destructively monitor the samples at each time point. In this study, a noninvasive imaging technology, optical coherence tomography (OCT), was utilized to characterize the in situ degradation of PLGA microspheres suspended within photo-crosslinked hyaluronic acid (HA) hydrogels. Microspheres with differing degradation rates were loaded with bovine serum albumin (BSA) as a marker protein, and temporal release of protein was correlated with morphological changes observed during 3-D OCT imaging. As proof-of-principle, a microsphere-loaded hydrogel scaffold was implanted in a modified rat calvarial critical size defect model and imaged using OCT. This animal model presents the opportunity to monitor microsphere degradation over time in living animals.
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA 98195 USA. jp98@u.washington.edu
authors.forename: Jennifer
authors.initials: J
authors.lastname: Patterson
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Stayton
authors.forename: Xingde
authors.initials: X
authors.lastname: Li
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry / Q000627:therapeutic use; D004337:Drug Carriers / Q000032:analysis / Q000737:chemistry / Q000627:therapeutic use; D004339:Drug Compounding; D004355:Drug Stability; D006820:Hyaluronic Acid / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry; D019344:Lactic Acid / Q000032:analysis* / Q000737:chemistry* / Q000627:therapeutic use; D008422:Materials Testing / Q000379:methods; D008863:Microspheres; D011100:Polyglycolic Acid / Q000032:analysis* / Q000737:chemistry* / Q000627:therapeutic use; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D012886:Skull / Q000601:surgery; D041623:Tomography, Optical Coherence
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D020100:Hydrogels; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D006820:Hyaluronic Acid