Miniature implanted and injected technologies capable of manipulating and recording biological signals promise to improve the way we study biology and the way we diagnose and treat disease; however, to create an effective bioelectronic network we must overcome myriad engineering challenges. In this talk, I will describe how we can leverage unique material properties to overcome some of these challenges. Specifically, I will show how magnetoelectric materials allow us to effectively transmit data and power to mm-sized devices deep inside the body. I will also describe how we can engineer fast magnetic control of genetically targeted neurons. Overall, these technologies provide a suite of miniature interfaces that could support next-generation brain-computer interfaces and closed-loop electronic medicine.