title: Cytoplasmic delivery of a macromolecular fluorescent probe by poly(d, l-lactic-co-glycolic acid) microspheres.
abstract: A macromolecular fluorescent probe encapsulated in poly(d, l-lactic-co-glycolic acid) (PLGA) microspheres was used as a model for studying cytoplasmic delivery of antigens. We hypothesized that Texas red dextran loaded in PLGA microspheres would be delivered to the cytoplasm and that cytoplasmic delivery would be affected by polymer molecular weight. Cellular localization of the Texas red dextran was investigated at two different molecular weights of PLGA: 6000 and 60,000 g/mol. Intracellular degradation and processing of Texas red dextran-loaded PLGA microspheres by mouse peritoneal macrophages was monitored both in vitro and in vivo for a 7-day period using confocal laser scanning microscopy (CLSM). The results revealed cytoplasmic delivery of the fluorescent probe at both molecular weights of PLGA. Furthermore, the CLSM images showed that both in vitro and in vivo, the kinetics of microsphere degradation and cytoplasmic delivery were more rapid for the 6000 g/mol PLGA microspheres than the 60,000 g/mol PLGA microspheres. Hence, this study provides physical evidence that PLGA microspheres are capable of cytoplasmic delivery and that delivery to the cytosol can be controlled by modifying formulation parameters such as polymer molecular weight.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta T6G 2N8, Canada.
authors.forename: K D
authors.initials: KD
authors.lastname: Newman
authors.forename: G S
authors.initials: GS
authors.lastname: Kwon
authors.forename: G G
authors.initials: GG
authors.lastname: Miller
authors.forename: V
authors.initials: V
authors.lastname: Chlumecky
authors.forename: J
authors.initials: J
authors.lastname: Samuel
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003593:Cytoplasm / Q000502:physiology; D004337:Drug Carriers; D005260:Female; D005456:Fluorescent Dyes; D019344:Lactic Acid; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008863:Microspheres; D010587:Phagocytosis; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers
chemical_list: D004337:Drug Carriers; D005456:Fluorescent Dyes; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid