Flexible Wireless Microsystem for Implantable Photodynamic Therapy in Bladder Cancer Treatment

Cancer is a highly prevalent disease and the incidence is rising in the developing nations. 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 the fabrication methodology of a new implantable PDT micro-system towards overcoming the constraints of current PDT treatments. We fabricated bio-compatible devices using laser ablation towards large area manufacturability, scalability, and repeatability. A wireless power transfer demonstration was implemented showing the electrical power delivery in a tissue phantom, emulating the bladder. The production of singlet oxygen (1O2) using an in-house developed LED system was studied by utilizing a 1,3-diphenylisobenzofuran (DPBF) in a Rose Bengal (RB) and Dimethyl sulfoxide (DMSO) solution. The photosensitizer solution is illuminated by a minimum of 5 mW of optical power produce by the four LED arrays to generate 1O2. Our measurements confirm the production of 1O2 emission 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. 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 as to enhance the curative efficiency of cancer treatment.