UC Irvine

The field of bioelectronics has the potential to revolutionize both fundamental biology and personalized medicine. As such, much research effort has been devoted to the development of devices and materials that are intrinsically compatible with biological systems. Within this context, several recent studies have focused on protonic transistors from naturally occurring materials, such as squid-derived polysaccharides and proteins. Herein, we report the rational design, fabrication, and characterization of protonic devices, for which the active material consists of a cephalopod protein-based proton conducting material known as reflectin. We first characterize the proton-conducting capabilities of reflectin, demonstrate reflectin-based two- and three-terminal protonic devices, and then investigate strategies for optimizing their performance. Next, we investigate the conductive properties of a reflectin isoform and then proceed to fabricate and characterize protonic devices where it serves as the active layer. We then investigate the properties of protonic devices featuring reflectin films doped with a small molecular photoacid, and show the selective enhancement of their electrical properties through an exogenous photophysical stimulus. Finally, we demonstrate reflectin-based protonic devices that mimic the color-changing functionality of natural iridophores in cephalopod skin. Altogether, our findings underscore the potential of reflectins as functional materials and hold significance for both developing novel color-changing technologies and the understanding and control of proton transport in both biological systems and bioelectronic platforms.