Synthesis and characterization of novel thermoresponsive-co-biodegradable hydrogels composed of N-isopropylacrylamide, poly(L-lactic acid), and dextran

Authors

  • Xiao Huang,

    1. Pennsylvania State University, Department of Surgery, Hershey, PA 17033
    Search for more papers by this author
  • Bishwa Ranjan Nayak,

    1. Pennsylvania State University, Department of Surgery, Hershey, PA 17033
    Current affiliation:
    1. Department of Polymer Science, The University of Southern Mississippi, Hattiesburg, MS 39406
    Search for more papers by this author
  • Tao Lu Lowe

    Corresponding author
    1. Pennsylvania State University, Department of Surgery, Hershey, PA 17033
    2. Pennsylvania State University, Department of Bioengineering, Hershey, PA 17033
    3. Pennsylvania State University, Department of Materials Science and Engineering, Hershey, PA 17033
    • Pennsylvania State University, Department of Materials Science and Engineering, Hershey, PA 17033
    Search for more papers by this author

Abstract

A series of novel multifunctional hydrogels that combined the merits of both thermoresponsive and biodegradable polymeric materials were designed, synthesized, and characterized. The hydrogels were copolymeric networks composed of N-isopropylacrylamide (NIPAAM) as a thermoresponsive component, poly(L-lactic acid) (PLLA) as a hydrolytically degradable and hydrophobic component, and dextran as an enzymatically degradable and hydrophilic component. The chemical structures of the hydrogels were characterized by an attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR) technique. The hydrogels were thermoresponsive, showing a lower critical solution temperature (LCST) at approximately 32 °C, and their swelling properties strongly depended on temperature changes, the balance of the hydrophilic/hydrophobic components, and the degradation of the PLLA component. The degradation of the hydrogels caused by hydrolytic cleavage of ester bonds in the PLLA component was faster at 25 °C below the LCST than at 37 °C above the LCST, determined by the ATR–FTIR technique. Due to their multifunctional properties, the designed hydrogels show great potential for biomedical applications, including drug delivery and tissue engineering. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5054–5066, 2004

Ancillary