Journal of Materials Science

, Volume 44, Issue 5, pp 1381–1387 | Cite as

Magnet–PNIPA hydrogels for bioengineering applications

  • R. V. RamanujanEmail author
  • K. L. Ang
  • S. Venkatraman


Temperature-sensitive Poly (N-isopropylacrylamide), PNIPA gels were synthesized with micron-sized iron and iron oxide (Fe3O4) particles to investigate their viability for hyperthermia applications. Induction heating of the magnetic hydrogels with varying concentration of magnetic powder was conducted at a frequency of 375  kHz for magnetic field strength varying from 1.7 kA/m (21 Oe) to 2.5 kA/m (31.4 Oe). It was observed that the maximum temperature induced in the magnetic hydrogels increased with the concentration of magnetic particles and magnetic field strength. The PNIPA gel underwent a collapse transition at 34 °C. It was found that a 2.5 wt.% Fe3O4 in PNIPA composite took 260 s to be heated to 45 °C under a magnetic field strength of 1.7 kA/m, the specific absorption rate (SAR) was found to be 1.83. SAR of iron oxide was found to be higher than the SAR of iron.


Magnetic Field Strength Magnetic Particle Lower Critical Solution Temperature PNIPA Hysteresis Loss 


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Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  1. 1.School of Materials Science and EngineeringNanyang Technological UniversitySingaporeSingapore

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