Implantable Light-Powered Human Designer Cells for Electrical Energy Generation

Herein, an implantable, miniature biohybrid device has been developed that utilizes light-dependent ion-gradient formation by genetically engineered human designer cells, expressing light-activated ion channels and proton pumps to generate electrical potential and deliver electrical energy. These designer cells are cultured in custom-designed polycarbonate chambers, connected by electrodes and separated from an ion reservoir by a proton-selective Nafion membrane. Upon illumination, the light-activated channels and pumps on the designer cells establish a sustained proton gradient across the Nafion membrane, which drives an electrical current in the external circuit. When exposed to simulated ambient sunlight of 3 mW cm^{- 2} of intensity, a single solar collection device (SCD), containing these designer cells, appropriately sized for subcutaneous implantation in mice, generates an electrical potential of ≈0.4 V. By connecting multiple SCDs in series and increasing the cell suspension volume, the output can be scaled up sufficiently to power a commercial light-emitting diode. Thus, this study demonstrates the feasibility of a photovoltaic system based on optogenetically engineered mammalian cells for powering bioelectronic implants or wearable devices.