Hyperthermia controlled rapid drug release from thermosensitive magnetic microgels

Rajesh Regmi, Shanta Raj Bhattarai, Chandran Sudakar, Amit S. Wani, Robert Cunningham, Prem P. Vaishnava, Ratna Naik, David Oupicky, Gavin Lawes

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Poly-N-isopropylacrylamide (PNIPAM), a biocompatible and thermosensitive polymer, exhibits reversible volume phase transition from a hydrophilic coil to hydrophobic globule at the lower critical solution temperature (LCST) of 305 K in an aqueous solution. To produce this conformational change solely by magnetic heating we incorporated magnetite nanoparticles (∼12 nm diameter) in the polymer. These PNIPAM/magnetite nanoparticle composites showed substantial heating when exposed to an alternating magnetic field. We report the non-invasive in vitro controlled release of anti-cancer drug mitoxantrone, which was loaded into the composite, driven solely by the heating induced by the external magnetic field. We found that the temperature of the composite reached 323 K in 4 min by magnetic heating, releasing 4% of the drug in this time, at an average effective release rate of 0.010 mg min-1 (corresponding to 1% per minute). We also present results on thermodynamic and magnetic anomalies near the LCST of the PNIPAM-Fe3O4 composite.

Original languageEnglish (US)
Pages (from-to)6158-6163
Number of pages6
JournalJournal of Materials Chemistry
Issue number29
StatePublished - Aug 7 2010
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Materials Chemistry


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