Cell scaffold blood-brain-barrier. (Credit: A. Marino/ Smart Bio-Interfaces, IIT Pontedera)

Photodynamic therapy (PDT) has largely been limited to surface cancers due to its inability to penetrate deeper than a centimeter of tissue. A new approach wirelessly delivers doses of light into deeper regions of the body to activate light-sensitive drugs, potentially enabling the use of PDT in treating a wider range of cancers such as those of the brain and liver.

In PDT, a light-sensitive drug is triggered by a specific light wavelength to produce a form of oxygen that kills nearby cancer cells. PDT also shrinks or destroys tumors by damaging blood vessels in the tumor and starving cancer cells of essential nutrients.

The team created a tiny 15 mm3 wireless device — weighing a mere 30 mg — that can be easily implanted in the body, thus allowing PDT to go deeper and target the inner organs. The team was able to activate photosensitive molecules through thick tissues of more than 3 cm, typically inaccessible by direct illumination.

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