Bioelectronic implants for brain stimulation provide critical tools for treating brain diseases as well as investigating fundamental biology but require invasive surgery. In this talk I will discuss a new class of implants which we named Circulatronics: wherein intravenously introduced bioelectronic devices travel through the body’s global internal roadways i.e., the circulatory system, and autonomously implant (without any external guidance) in the target brain region, circumventing the need for any surgery. I will present how this enables targeted focal neuromodulation of deep brain regions in rodents. To achieve this, we built subcellular-sized wireless energy harvesting electronics with high power conversion efficiency and integrated them with cells to create unique cell-electronics hybrids. Thus, we fused electronic functionality with the biological transport and targeting capabilities of living cells. This technology can form the foundation for autonomously implanting bioelectronics with unprecedented access to the human body without surgery, opening new avenues for healthcare and research.