UC Santa Cruz

Bioelectronics is an exciting field that combines electrical and computer engineering, materials science, and biotechnology to develop new tools and therapeutics for the health challenges facing society. Iontronics is a subdiscipline within this field that is concerned with electronics that operate using ions as a charge or information carrier. Iontronics devices have a promising application as interfaces between electronic and biological systems as they can control ion concentration gradients and perform charged molecule delivery in the biological milieu. Protonics is an aspect of iontronics that deals with the movement of protons. Early works on bio-protonic devices displayed the application of these devices towards sensing and control of biological components such as enzymes and membrane-bound ion channels in the form of specialized proton pumps, and pH actuators. The next major step in the maturation of iontronic and protonic devices towards bioelectronics is the design, fabrication, and realization of these devices in in vitro and in vivo settings.

This work explores the development of bioprotonic devices for in vitro and in vivo applications. Along the way, protonic biosensors and actuators are discussed. For in vivo applications, I discuss a non-enzymatic glucose biosensor that is activated by pH-shifting protonic electrodes and paves the way for metal-oxide biosensors implants. In vitro applications are explored in the context of protonic ion pump actuators. First, I present the development of proton pumps designed to break the buffer capacity of biological media using high-capacity palladium nanoparticle electrodes as a proton sink and source. Then, I iterate on this proton pump design to incorporate microfluidics for the long-term control of the membrane potential of stem cells that are cultured on-chip. Finally, I introduce adaptive machine-learning as a control method for closed-loop experiments with these bioelectronic devices. These results contribute to the field of bioelectronics by introducing new means for interacting biology in the form of biocompatible iontronic biosensors, protonic ion pumps for long-term cell experiments, and closed-loop control methods for long-term experimentation.