title: Influence of LA and GA sequence in the PLGA block on the properties of thermogelling PLGA-PEG-PLGA block copolymers.
abstract: This paper reports the influence of sequence structures of block copolymers composed of poly(lactic acid-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) on their thermogelling aqueous behaviors. A series of thermogelling PLGA-PEG-PLGA triblock copolymers with similar chemical compositions and block lengths but different sequences of D,L-lactide (LA) and glycolide (GA) in the PLGA block were synthesized. The difference of sequence structures arises from the different reactivities of LA and GA during the copolymerization and the transesterification after polymerization. The sol-gel transition temperature and height of gel window were found to be regulated by the sequence structure. Our study reveals that the macromolecular sequence structure influences the hydrophobic/hydrophilic balance of this kind of amphiphilic copolymers and thus alters mesoscopic micellization and the forthcoming macroscopic physical gelation in water. This finding might be helpful to guide the molecular design of the underlying thermogelling systems as injectable hydrogels.
authors.affiliation: Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Department of Macromolecular Science, Fudan University, Shanghai 200433, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jiandong
authors.initials: J
authors.lastname: Ding
mesh_terms: D002850:Chromatography, Gel; D019344:Lactic Acid / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D011092:Polyethylene Glycols / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012212:Rheology
chemical_list: D008823:Micelles; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols