Please use this identifier to cite or link to this item: https://doi.org/10.1163/156856206777656553
Title: Self-association and micelle formation of biodegradable poly(ethylene glycol)-poly(L-lactic acid) amphiphilic di-block co-polymers
Authors: Jongpaiboonkit, L.
Zhou, Z.
Ni, X.
Wang, Y.-Z.
Li, J. 
Keywords: Block co-polymer
Critical micelle concentration
Poly(ethylene glycol)
Poly(L-lactic acid)
Polymeric micelles
Self-association
Issue Date: Jul-2006
Source: Jongpaiboonkit, L.,Zhou, Z.,Ni, X.,Wang, Y.-Z.,Li, J. (2006-07). Self-association and micelle formation of biodegradable poly(ethylene glycol)-poly(L-lactic acid) amphiphilic di-block co-polymers. Journal of Biomaterials Science, Polymer Edition 17 (7) : 747-763. ScholarBank@NUS Repository. https://doi.org/10.1163/156856206777656553
Abstract: Di-block co-polymers of poly(ethylene glycol)-poly(L-lactic acid) (PEG-PLLA) were prepared by ring-opening polymerization, and their self-association and micelle formation were investigated. The block co-polymers have the same block length of the hydrophilic PEG segment (Mn = 2000), but different chain lengths of the hydrophobic PLLA segment (Mn = 700, 1000 and 1300, respectively). The di-block co-polymers synthesized were characterized by GPC, 1 H-NMR, TGA and DSC. The critical micelle concentration (CMC) of the PEG-PLLA micelles was determined at various temperatures (5-45°C) using a dye absorption technique involving fluorescence spectrophotometry with pyrene as a probe to monitor the change in the polarity of the microenvironment in the micelle. An increase in the molecular weight of the hydrophobic block decreases the CMC. The partition coefficients of pyrene between the micellar and aqueous phases range from 0.68 × 104 to 1.76 × 104, depending on the PLLA content in the block co-polymers. An Arrhenius plot of ln(CMC) versus 1/T exhibited an almost constant CMC at low temperatures (35°C). The increase of the CMC with temperature indicates the increase of the mobility of the hydrophobic PLLA core. These results were confirmed by 1H-NMR measurements. The micelle size and size distribution were determined by dynamic light scattering (DLS), and were in the range of 78-92 nm. A spherical micelle shape was confirmed by transmission electron microscopy. These results indicate that the CMC and the thermal characteristics of the core-forming segment of the block co-polymer play an important role in the properties of the polymer micelles used for drug delivery. © VSP 2006.
Source Title: Journal of Biomaterials Science, Polymer Edition
URI: http://scholarbank.nus.edu.sg/handle/10635/88119
ISSN: 09205063
DOI: 10.1163/156856206777656553
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

26
checked on Feb 12, 2018

Page view(s)

27
checked on Feb 16, 2018

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.