| Nov 23, 2010 |
Magnetic field directs nanoparticles to tumors
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(Nanowerk News) To improve the tumor-specific delivery of drug to tumors, a team of investigators from the University of California, San Diego (UCSD) has created a system of nanoparticles-within-a-nanoparticle that can be directed to and concentrated at the site of tumor using a magnetic field. Once at the tumor site, radiofrequency irradiation triggers drug release from the nanoparticles, bathing the tumors in drug and markedly reducing the growth of the tumors.
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Reporting its work in the journal Nano Letters ("Magnetically Vectored Nanocapsules for Tumor Penetration and Remotely Switchable On-Demand Drug Release"), a research team led by Sungho Jin described the multiple steps it uses to create these multi-component nanoparticles that contain both magnetic nanoparticles and the drug Camptothecin trapped within a silica shell. Trapped within the silica nanoparticle, the close proximity of the hundreds of magnetic iron oxide nanoparticles boosts their responsiveness to a magnetic field applied from outside the body. More importantly, at moderate magnetic field strengths the nanoparticles not only accumulate in the vicinity of a tumor but also penetrate into the tumor mass.
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Based on these initial results, the investigators injected the nanoparticles into mice implanted with human breast tumors. After using a magnetic field to direct the nanoparticles to tumors during a two-hour period, the researchers subjected the animals to three 8-minute exposures to radiofrequency irradiation. The treated animals experienced a marked reduction in the size of their tumors and experienced no noticeable side effects.
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