AsianScientist (Sep. 19, 2018) – Scientists from Waseda University, the National Defense Medical College and the Japan Science and Technology Agency in Japan have developed a bioadhesive, wirelessly-powered light-emitting device which could better treat cancers in delicate organs. They published their findings in Nature Biomedical Engineering.
Conventional photodynamic therapy induces cancer cell death by using photosensitizing agents which localize in tumors and activate with exposure to a specific wavelength of light. In recent years, low-dose and long-term photodynamic therapy (metronomic photodynamic therapy, mPDT) has shown promise in treating cancers in internal organs.
The problem with mPDT is, however, is that the extremely low light intensity (1/1000 of the conventional method) means that antitumor effects cannot be obtained if the light source shifts even slightly away from the tumor.
In the present study, researchers led by Associate Professor Toshinori Fujie of Waseda University and his collaborators developed a wirelessly-powered optoelectronic device that stably fixes itself onto the inner surface of an animal tissue like a sticker with bioadhesive and elastic nanosheets.
The nanosheets are modified with a mussel adhesive protein-inspired polymer polydopamine, which can stabilize the device onto wet animal tissue for more than two weeks without surgical suturing or medical glue. The light-emitting diode chips in the device are wirelessly powered by near-field communication technology.
To test the effectiveness of their device, the researchers implanted it into tumor-bearing mice which had been injected with a photosensitizing agent (photofrin). The researchers then illuminated the tumors for ten consecutive days with red and green light approximately 1,000-fold lower in intensity than conventional PDT approaches. They found that tumor growth was significantly reduced, especially under green light, wherein the tumors in some mice were completely eradicated.
“This device may facilitate treatment for hard-to-detect microtumors and deeply located lesions that are hard to reach with standard phototherapy, without having to worry about the risk of damaging healthy tissues by overheating,” said Fujie.
“Furthermore, because the device does not require surgical suturing, it is suitable for treating cancer near major nerves and blood vessels, as well as for organs that are fragile, that change their shape, or that actively move, such as the brain, liver and pancreas.”
The article can be found at: Yamagishi et al. (2018) Tissue-adhesive Wirelessly Powered Optoelectronic Device for Metronomic Photodynamic Cancer Therapy.
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Source: Waseda University; Photo: Shutterstock.
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