A flexible wireless system for prospective photodynamic therapy applications

Cancer treatments, dependent on several factors, deliver varying degrees of treatment effectiveness. Photodynamic therapy (PDT) is a treatment modality that selectively targets and destroys cancer cells using a light-sensitive drug with a specific optical wavelength. However, PDT encounters several constraints, mainly, limited penetration of light into deep tumors. In this paper, we present a new wireless implantable PDT system towards overcoming the constraints of current PDT treatments. The wireless-powered prototype was evaluated showing resonant inductive power delivery in a tissue phantom, emulating the bladder, providing the necessary power level for PDT treatment. The production of singlet oxygen (¹O₂) using a multi-LED system was studied by utilizing a 1,3-diphenylisobenzofuran (DPBF) in a Rose Bengal (RB) and Dimethyl sulfoxide (DMSO) solution, under both DC and AC excitations, for direct wireless powering. The photosensitizer solution is illuminated with over 5 mW of optical power generated by the four-LED array to generate ¹O₂. Our measurements confirm the production of ¹O₂ emissions as well as lifetime performance. The optical, electrical, and mechanical studies are presented on the resultant optoelectronic system, verifying the efficiency and mechanical robustness of our prototype. A fabrication flow for bio-compatible devices using laser ablation is also introduced towards large area manufacturability, scalability, and repeatability. Our manufacturing process is versatile to a variety of materials including polymeric substrates, metallic electrodes and offers design flexibility ranging from 30 microns to mm. This research advances the development of wirelessly powered implantable device for PDT, optimized for in-vivo use through careful LED selection and biocompatible design. Our results evidence the potential of a new emergent technology that addresses the limitations of PDT as a potential future therapy to enhance the curative efficiency of cancer treatment and demonstrates promising preliminary potential for in vivo application, which requires further validation before therapeutic implementation can be established.