title: A biodegradable vascularizing membrane: a feasibility study.
abstract: Regenerative medicine and in vivo biosensor applications require the formation of mature vascular networks for long-term success. This study investigated whether biodegradable porous membranes could induce the formation of a vascularized fibrous capsule and, if so, the effect of degradation kinetics on neovascularization. Poly(l-lactic acid) (PLLA) and poly(dl-lactic-co-glycolic) acid (PLGA) membranes were created by a solvent casting/salt leaching method. Specifically, PLLA, PLGA 75:25 and PLGA 50:50 polymers were used to vary degradation kinetics. The membranes were designed to have an average 60mum pore diameter, as this pore size has been shown to be optimal for inducing blood vessel formation around nondegradable polymer materials. Membrane samples were imaged by scanning electron microscopy at several time points during in vitro degradation to assess any changes in pore structure. The in vivo performance of the membranes was assessed in Sprague-Dawley rats by measuring vascularization within the fibrous capsule that forms adjacent to implants. The vascular density within 100microm of the membranes was compared with that seen in normal tissue, and to that surrounding the commercially available vascularizing membrane TheraCyte. The hemoglobin content of tissue containing the membranes was measured by four-dimensional elastic light scattering as a novel method to assess tissue perfusion. Results from this study show that slow-degrading membranes induce greater amounts of neovascularization and a thinner fibrous capsule relative to fast degrading membranes. These results may be due both to an initially increased number of macrophages surrounding the slower degrading membranes and to the maintenance of their initial pore structure.
authors.affiliation: Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road E310, Evanston, IL 60208, USA.
authors.forename: Anchal
authors.initials: A
authors.lastname: Kaushiva
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Turzhitsky
authors.forename: Marissa
authors.initials: M
authors.lastname: Darmoc
authors.forename: Vadim
authors.initials: V
authors.lastname: Backman
authors.forename: Guillermo A
authors.initials: GA
authors.lastname: Ameer
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D005240:Feasibility Studies; D048091:Guided Tissue Regeneration / Q000295:instrumentation / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D008567:Membranes, Artificial; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial; D011091:Polyesters; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide)