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Temperature sensitivity and drug encapsulation of star‐shaped amphiphilic block copolymer based on dendritic poly(ether‐amide)
Author(s) -
Yang Zhu,
Xie Jianda,
Zhou Wei,
Shi Wenfang
Publication year - 2008
Publication title -
journal of biomedical materials research part a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.849
H-Index - 150
eISSN - 1552-4965
pISSN - 1549-3296
DOI - 10.1002/jbm.a.31881
Subject(s) - materials science , lower critical solution temperature , micelle , copolymer , dynamic light scattering , polymer chemistry , amphiphile , polymerization , polymer , chemical engineering , hydrodynamic radius , ether , caprolactone , ring opening polymerization , nanoparticle , organic chemistry , composite material , nanotechnology , chemistry , aqueous solution , engineering
The star‐shaped amphiphilic block copolymer (DPEA‐PCL‐PNIPAAms) with different PCL block lengths was prepared through ring opening polymerization of ε‐caprolactone (CL) initiated by hydroxyl end‐capped dendritic poly(ether‐amide) (DPEA‐OH), and then coupling with carboxyl end‐capped linear poly( N ‐isopropylacrylamide) (PNIPAAm‐COOH) via an esterification process. The molecular structure was characterized by FT‐IR, 1 H NMR, and GPC analysis. As the copolymer dissolved in water, the core‐shell structural nanoparticle was formed as a micelle. The fluorescence, 1 H NMR, and dynamic light scattering (DLS) techniques were utilized to confirm the formation of micelles. The optical transmittance and US‐DSC measurements demonstrated that the micelles performed the reversible dispersion/aggregation behavior in response to temperature through the outer PNIPAAm polymer shell. The micelles loaded with daidzein showed a very rapid drug release speed at temperatures above the lower critical solution temperature (LCST) due to the temperature‐induced structural change of the polymeric micelles. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009