Controlled drug release from hydrogel nanoparticle networks

Gang Huang, Jun Gao, Zhibing Hu, John V. St. John, Bill C. Ponder, Dan Moro

Research output: Contribution to journalArticlepeer-review

97 Scopus citations


Monodisperse nanoparticles of poly-N-isopropylacrylamide-co-allylamine (PNIPAM-co-allylamine) and PNIPAM-co-acrylic acid (PNIPAM-co-AA) were synthesized. The close-packed PNIPAM-co-allylamine and PNIPAM-co-AA nanoparticles were converted to three-dimensional gel networks by covalently crosslinking neighboring particles at room temperature and neutral pH using glutaric dialdehyde and adipic acid dihydrazide, respectively. Controlled release studies were conducted using dextran markers of various molecular weights as model macromolecular drugs. Release was quantified under various physical conditions, including a range of temperatures and dextran molecular weights. Dextran, entrapped in cavities in the nanoparticle network, was released with a rate regulated by their molecular weights and cavity size. No release from a conventional bulk PNIPAM gel, with high crosslinking density, was observed. The rate of release from the PNIPAM-co-allylamine network was temperature-dependant, being much faster at room temperature than that at human body temperature. In contrast, release of low molecular weight dextrans from the PNIPAM-co-AA network showed a temperature-independent release profile. These nanoparticle networks have several advantages over conventional bulk gels for controlling the release of high molecular weight biomolecules.

Original languageEnglish (US)
Pages (from-to)303-311
Number of pages9
JournalJournal of Controlled Release
Issue number2-3
StatePublished - Feb 10 2004


  • Controlled release
  • Gel
  • N- Isopropylacrylamide
  • Nanoparticles
  • Nanostructures
  • Thermoresponsive gel

ASJC Scopus subject areas

  • Pharmaceutical Science


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