A Wireless, Implantable, Multi-Color Fluorescence Image Sensor for Monitoring Response to Cancer Therapy
Implantable sensors capable of real-time monitoring of complex cellular dynamics can provide critical information for understanding disease progression and treatment response, leading to more personalized medicine. An impactful application is in cancer immunotherapy which produces durable responses but suffers from low response rates (<50%). Multicolor fluorescence microscopy is a critical tool for the study of multi-cell type dynamics but limited optical penetration depth (<5mm for 400-900nm) and bulky optics constrain its use in vivo. Therefore, wireless, miniaturized, chip-based, fluorescence imagers with in-package light sources, and multicolor (multi-cell type) sensing are needed for real-time monitoring within the body. Prior work has demonstrated miniaturized chip-based
fluorescence imagers, but relies on wired power and communication [1-2] or batteries [3] and lacks wireless charging capabilities, precluding untethered chronic implantation. Moreover, multi-bandpass filters for multicolor imaging were not shown with these systems. Here we present a fully wireless, implantable multicolor fluorescence image sensor with in-package light sources. Wired connections and batteries are eliminated by power harvesting and bi-directional communication through ultrasound (US), which offers low loss in tissue. Our system operates at 5cm depth with 221mW/cm2 of US power flux density (31% of US safety limits), indicating suitability for chronic use. A proof-of-concept package demonstrates the smallest form factor (0.09cm3) among prior work. The imaging frontend consumes 2.09mW including readout. Moreover, the system is designed specifically for 3-color fluorescence imaging with a 510μm-thick optical frontend comprising a multi-bandpass interference filter deposited on a fiber optic plate (FOP).
Expected Graduation Date:
May, 2026
