Wireless in-body sensing through genetically engineered bacteria.

This paper introduces a class of wireless implantable sensors that integrate genetically engineered cells capable of detecting specific molecules for continuous monitoring. While synthetic biology enables cells to sense molecular targets, wireless communication of this information remains a challenge. Electromagnetic (EM) waves at cellular-scale wavelengths are strongly attenuated in tissue, necessitating centimeter-scale wavelengths for in-body links. Aligning cellular responses with these longer EM wavelengths enables effective interaction. In this work, the response of Escherichia coli is harnessed to trigger the controlled degradation of a passive microwave antenna, which is then monitored via backscatter communication. This approach converts cellular activity into detectable EM signals, eliminating the need for batteries or circuits. We demonstrate a wireless link between a passive, cell-based sensor in a human body phantom and an external receiver, achieving molecular-level sensing at 25 mm implant depth. Future implementations could couple bacterial responses to diverse molecular targets.