An ultrasonically powered implantable micro-light source for localized photodynamic therapy

In this work, we introduce an ultrasonically powered light source which can provide in situ localized light for photodynamic therapy. The implants are 2×2×2 mm³ and 2×4×2 mm³ in dimensions and consist of two red LEDs mounted on a piezoelectric energy source. Such device is small enough to be easily implanted inside solid tumors using a biopsy needle. In vitro light intensity measurements show an output power density of 48 μW/cm² from the 2×2×2 mm³ and 1.1 mW/cm² from the 2×4×2 mm³ light source. The results indicate that implanting multiple sources and powering them for 1 hour can provide optimal energy for localized photodynamic therapy.