PDT is a treatment method that uses a light sensitive drug, called a photosensitiser, that is triggered by a specific wavelength of light to produce a form of oxygen that kills nearby cells.
The team at National University of Singapore (NUS) say that this approach will overcome the current limitations of PDT treatment and enable it to be used on the inner organs of the body – rather than just on surface cancers – with fine control.
The team hope that the technology could be used to treat a wider range of cancer.
Assistant Professor John Ho from NUS, said: “Our approach of light delivery will provide significant advantages for treating cancers with PDT in previously inaccessible regions. Powered wirelessly, the tiny implantable device delivers doses of light over long time scales in a programmable and repeatable manner. This could potentially enable the therapies to be tailored by the clinician during the course of treatment.”
The NUS team’s approach works by inserting a miniaturised wireless device at the target site, which extends the spatial and temporal precision of PDT deep within the body.
The device, which is said to weigh 30 mg and is 15 mm3 in size, is implanted at the target site. A specialised radio-frequency system apparently then wirelessly powers the device and monitors the light-dosing rate.
The team claim to have demonstrated the therapeutic efficacy of this approach by activating photosensitisers through thick tissues – more than three centimetres – inaccessible by direct illumination, and by delivering multiple controlled doses of light to suppress tumour growth.
“This novel approach enables ongoing treatment to prevent reoccurrence of a cancer, without additional surgery. The application of the technology can also be extended to many other light-based therapies, such as photothermal therapy, that face the common problem of limited penetration depth. We hope to bring these capabilities from bench to beside to provide new opportunities to shine light on human diseases,” said Professor Zhang Yong of NUS.
The team are now focusing on developing nanosystems for targeted delivery of photosensitisers, devising minimally invasive techniques for implanting the wireless devices at the target site and looking into integrating sensors to monitor the treatment response in real-time.
