Synthesis, properties and self-assembly of intelligent core-shell nanoparticles based on chitosan with different molecular weight and N-isopropylacrylamide

Authors

  • Yajing Wang,

    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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    • Y. W. and J. W. contributed equally to this article.

  • Jiu Wang,

    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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    • Y. W. and J. W. contributed equally to this article.

  • Liang Ge,

    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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  • Qi Liu,

    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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  • Liqun Jiang,

    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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  • Jiabi Zhu,

    Corresponding author
    1. Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
    • Pharmaceutical Research Institute, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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  • Jianping Zhou,

    1. Department of Pharmaceutics, China Pharmaceutical University, Nanjing, Jiangsu Province 210009, China
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  • Fei Xiong

    1. State Key Laboratory of Bioelectronics, Jiangsu Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu Province 210009, China
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Abstract

In this study, a series of chitosan-graft-poly(N-isopropylacrylamide) (CTS-g-PNIPAAm) copolymers based on different molecular weight (Mw) of CTS and NIPAAm were synthesized through the polymerization of NIPAAm in an acid aqueous solution. The structures were verified by Fourier transform infrared and nuclear magnetic resonance. The influence of the CTS Mw on the properties of the resulting copolymers and self-assembled nanoparticles was fully examined. The grafting ratio and grafting efficiency of the copolymers increased with the CTS Mw. All the copolymers have a similar low critical solution temperature of 33.5°C, which was independent of the CTS Mw. Furthermore, the copolymers were less temperature sensitive, when CTS Mw increased to 200 kDa. Besides, once the CTS Mw increased to 700 kDa, the copolymers were less pH sensitive near the tumor site (from pH 7.4 to 6.8). The copolymers could form uniform nanoparticles once the temperature increased to 34°C, which was reversible. After crosslinking by N,N-methylenebisacrylamide (MBA), structurally stable nanoparticles could be obtained. The results from Transmission electron microscope (TEM) and Atomic force microscopy (AFM) showed that the MBA crosslinked nanoparticles were uniformly spherical with a loose structure. Surface tension method indicated that the critical aggregate concentrations were 0.045, 0.042, 0.037, and 0.036 mg mL−1 prepared from CTS 50, 100, 200, and 700 kDa, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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