Fully implantable and battery-free wireless optoelectronic system for modulable cancer therapy and real-time monitoring

Photodynamic therapy (PDT) is attracting attention as a next-generation cancer treatment that can selectively destroy malignant tissues, exhibit fewer side effects, and lack pain during treatments. Implantable PDT systems have recently been developed to resolve the issues of bulky and expensive conventional PDT systems and to implement continuous and repetitive treatment. Existing implantable PDT systems, however, are not able to perform multiple functions simultaneously, such as modulating light intensity, measuring, and transmitting tumor-related data, resulting in the complexity of cancer treatment. Here, we introduce a flexible and fully implantable wireless optoelectronic system capable of continuous and effective cancer treatment by fusing PDT and hyperthermia and enabling tumor size monitoring in real-time. This system exploits micro inorganic light-emitting diodes (μ-LED) that emit light with a wavelength of 624 nm, designed not to affect surrounding normal tissues by utilizing a fully programmable light intensity of μ-LED and precisely monitoring the tumor size by Si phototransistor during a long-term implantation (2–3 weeks). The superiority of simultaneous cancer treatment and tumor size monitoring capabilities of our system operated by wireless power and data transmissions with a cell phone was confirmed through in vitro experiments, ray-tracing simulation results, and a tumor xenograft mouse model in vivo. This all-in-one single system for cancer treatment offers opportunities to not only enable effective treatment of tumors located deep in the tissue but also enable precise and continuous monitoring of tumor size in real-time.