Office of Technology Transfer – University of Michigan

Effective photothermal therapy using magnetic nanoparticles

Technology #5806

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Hongwei Chen
Managed By
Tiefei Dong
Senior Licensing Specialist, Life Sciences 734-763-5332
Patent Protection
US Patent Pending

Administered magnetic nanoparticles aggregate in solid tumors and absorb near-infrared radiation to destroy tumor cells. Currently, gold nanostructures are used in photothermal therapy (PTT) as near-infrared-absorbing nanoparticles. However, gold nanoparticles can undergo melting with laser treatment, are too large to effectively accumulate in solid tumors, and require multiple steps for development. In contrast, polysiloxane-containing magnetic nanoparticles are small (15 nm), aggregate efficiently in solid tumors, and are easy to develop. Magnetic nanocrystals will enhance photothermal therapy applications for solid tumors.

Near-infrared-absorbing magnetic nanoparticles for photothermal therapy

Magnetic nanocrystals absorb near-infrared radiation and greatly increase their temperature relative to near-infrared radiation-treated water. Magnetic nanocrystals, when injected into solid tumor-bearing mice, accumulated in the tumor tissue. Applying near-infrared radiation to magnetic nanocrystals containing tumors resulted in complete tumor disappearance within three weeks without tumor regrowth for over three months. Compared to gold nanoparticles, magnetic nanoparticles are smaller, more stable after heating, and easier to develop. Combining magnetic nanoparticles with MRI contrast agent will enable dual modal photothermal therapy (imaging plus treatment). With thousands of new cases of cancer per state each year, magnetic nanoparticles could be used widely in photothermal therapy for treatment of a variety of solid tumors.


  • Combined with MRI contrasting agent – dual modal photothermal therapy
  • Treatment of solid tumors with photothermal therapy


  • Smaller (15 nm) compared to conventional gold-containing nanoparticles
  • Easily developed and scalable
  • Non-toxic
  • Multifunctional (combine with MRI imaging)