| Stimuli-responsive zwitterionic block copolypeptides: poly(N-isopropylacrylamide)-block-poly(lysine-co-glutamic acid). | |
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MedLine Citation:
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PMID: 18759410 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Synthesis of novel zwitterionic block copolypeptides, poly(N-isopropylacrylamide)-block-poly(L-glutamic acid-co-L-lysine) [PNiPAM(n)(PLG(x)-co-PLLys(y))m , where n is the number-average degree of polymerization (DP(n)) of PNiPAM block, x and y are the mole fraction of glutamic acid and lysine residues, respectively, and m is the total DP(n) of the peptide block], and their stimuli-responsiveness to temperature and pH variation in aqueous solutions are described. Initiated with the amino-terminated poly(N-isopropylacrylamide) (PNiPAM(n)-NH2), ring-opening polymerization (ROP) of a mixture of gamma-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA), and Boc-L-lysine N-carboxyanhydride (BLLys-NCA) afforded the block copolypeptides PNiPAM(n)(PBLG(x)-co-PBLLys(y))m, with a poly(N-isopropylacrylamide) block together with a random copolypeptide block, which was then deprotected with HBr/trifluoroacetic acid into the double hydrophilic block copolypeptides, PNiPAM(n)(PLG(x)-co-PLLys(y))m. Their block ratios and lengths, as well as the amino acid residue ratios in the random copolypeptide block are varied (n = 360, x = 0.4-0.5, y = 0.4-0.6, and m = 220-252). The secondary structures of the copolypeptides in aqueous solution at different pH conditions were examined. Phase transitions in aqueous solutions induced by both pH and temperature variation were investigated by (1)H NMR spectroscopy. The transitions induced by temperature were also explored by turbidity measurements using UV/vis spectroscopy for their lower critical aggregation temperature (LCAT) determination. Furthermore, these aggregation processes were followed by dynamic light scattering measurements. |
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Authors:
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Jingguo Li; Tao Wang; Dalin Wu; Xiuqiang Zhang; Jiatao Yan; Song Du; Yifei Guo; Jintao Wang; Afang Zhang |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-08-29 |
Journal Detail:
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Title: Biomacromolecules Volume: 9 ISSN: 1526-4602 ISO Abbreviation: Biomacromolecules Publication Date: 2008 Oct |
Date Detail:
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Created Date: 2008-10-14 Completed Date: 2009-05-01 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100892849 Medline TA: Biomacromolecules Country: United States |
Other Details:
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Languages: eng Pagination: 2670-6 Citation Subset: IM |
Affiliation:
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School of Materials Science and Engineering, Zhengzhou University, Daxue Beilu 75, Zhengzhou 450052, China. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Acrylic Resins
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chemistry* Biocompatible Materials / chemistry* Circular Dichroism Glutamic Acid / chemistry Hydrogen-Ion Concentration Light Lysine / chemistry Magnetic Resonance Spectroscopy Materials Testing Molecular Conformation Peptides / chemistry* Polymers / chemistry Scattering, Radiation Spectrophotometry, Ultraviolet / methods Temperature |
| Chemical | |
Reg. No./Substance:
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0/Acrylic Resins; 0/Biocompatible Materials; 0/Peptides; 0/Polymers; 25189-55-3/poly-N-isopropylacrylamide; 56-86-0/Glutamic Acid; 56-87-1/Lysine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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