title: Development and in vitro characterization of vascular endothelial growth factor (VEGF)-loaded poly(DL-lactic-co-glycolic acid)/poly(ethylene glycol) microspheres using a solid encapsulation/single emulsion/solvent extraction technique.
abstract: Poly(DL-lactide-co-glycolide) (PLGA)/polyethylene glycol (PEG) microspheres are one modality of controlled delivery of biologically active molecules that would further the development of engineered tissues. As a possible mechanism to stimulate angiogenesis within an engineered tissue, vascular endothelial growth factor (VEGF) and bovine serum albumin (BSA) were coencapsulated into microspheres fabricated from PEG and 50/50 PLGA using a solid-encapsulation/single-emulsion/solvent extraction technique. Two VEGF/BSA ratios were studied: 1:2000 and 1:10,000. Analysis consisted of the loading efficiency, particle size distribution, bright-field microscopy, scanning electron microscopy, release kinetics, and an in vitro human umbilical vein endothelial cell proliferation assay to assess biological activity of the released VEGF. Results show the microspheres could be manufactured, stored, and degraded over 28 days. The burst release rates for 1:2000 and 1:10,000 VEGF/BSA microspheres were 71.87 +/- 8.11 and 27.91 +/- 1.71 ng/mL (mean +/- standard error of the mean), respectively; steady-state release rates were 6.56 +/- 1.10 and 2.21 +/- 0.47 ng/mL, respectively. The microspheres released biologically active VEGF, and the VEGF increased the proliferation of HUVECs in culture (p <.05). The successful development of a novel, cost-effective, scalable technique for producing microspheres loaded with biologically active proteins is presented. Using the data obtained from these studies, a defined concentration of microspheres will deliver a quantifiable level of VEGF at a known release rate.
authors.affiliation: Laboratory of Reparative Biology and Bioengineering, Department of Plastic Surgery, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 62, Houston, Texas 77030, USA.
authors.forename: T W
authors.initials: TW
authors.lastname: King
authors.forename: C W
authors.initials: CW
authors.lastname: Patrick
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001698:Biomedical Engineering; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems; D004655:Emulsions; D016228:Endothelial Growth Factors / Q000008:administration & dosage*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008222:Lymphokines / Q000008:administration & dosage*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011092:Polyethylene Glycols; D011098:Polyglactin 910; D011994:Recombinant Proteins / Q000008:administration & dosage; D012997:Solvents; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D004655:Emulsions; D016228:Endothelial Growth Factors; D008222:Lymphokines; D011994:Recombinant Proteins; D012997:Solvents; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C102418:poly(lactic-glycolic acid)-poly(ethyleneglycol) copolymer; D011098:Polyglactin 910; D011092:Polyethylene Glycols