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  • Influence of LA and GA sequence in the PLGA block on the properties of thermogelling PLGA-PEG-PLGA block copolymers.

Influence of LA and GA sequence in the PLGA block on the properties of thermogelling PLGA-PEG-PLGA block copolymers.

Biomacromolecules (2011-03-03)
Lin Yu, Zheng Zhang, Jiandong Ding
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.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
3-Methyl Glycolide, ≥98%
Sigma-Aldrich
Redox Responsive Poly(ethylene glycol)-block-poly(lactide-alt-glycolide), PEG average Mn 5000, PLGA Mn 15000
Sigma-Aldrich
Poly(ethylene glycol)-block-poly(lactide-alt-glycolide), PEG average Mn 5,000, PLGA Mn 15,000
Sigma-Aldrich
Poly(lactide-alt-glycolide), average Mn 20,000, 50:50 (lactide:glycolide)
Sigma-Aldrich
Poly(lactide-alt-glycolide), average Mn 10000, lactide:glycolide 50:50