(6je) Biomaterials-­based Charge Storage Devices for Edible Electronics

Organic compounds represent promising alternatives to inorganic materials as renewable and sustainable energy storage devices. Organic molecules can be processed into non-conventional form factors, are cost-effective, and exhibit reduced toxicity compared to other exotic inorganic materials. Naturally-occurring biomaterials would be more advantageous due to exceptional biodegradability/biocompatibility and known cytotoxicity. Many researches have shown the potential use of biologically-derived materials into electronics devices. Such devices include organic transistors, biological sensors, and thermal-electric materials.

I am especially interested in using eumelanin pigments as charge storage materials.¹ Eumelanins are extended heterogeneous biopolymers composed of molecular subunits of dihydroxyindole (DHI) and dihydroxyindole-carboxylic acid (DHICA) with ambiguous macromolecular topology. Eumelanins exhibit unique properties such as hydration-dependent hybrid ionic electronic conductivity as well as electrochemical redox activity, which lead to promising biomaterial-based electrodes for aqueous Na⁺ or Mg²⁺ charge storage devices.² Although the molecular composition of natural eumelanin pigments is understood, little is known about the macromolecular topology that links DHI and DHICA subunits. Understanding the macromolecular structure of eumelanins could provide insight into the self-assembly mechanisms employed by protein templates during natural melanogenesis and the origin of bulk optoelectronic properties.

Biomaterials-based charge storage devices will further be applied to power “edible electronics” devices for biomedical applications.³ Edible electronics is the emerging strategy of delivering electronics devices through GI-tract. A variety of potential advantages include safer diagnosis, quicker therapies, and programmable drug delivery. Eumelanin pigments would be beneficial for powering these classes of transient electronics devices.

Interconnection between biological systems and electrical devices require interdisciplinary approach that incorporates the aspect of synthesis of polymeric network, microfabrication techniques, device design, and biotic/abiotic interface. My research program will lead an interdisciplinary group of understanding the functionality of biomaterials and applying them into a synthetic approach to build the charge storage devices and further develop biomedical and electronics devices.

References

(1) Kim, YJ; Wu, W; Chun, S-E; Whitacre, JF; Bettinger, CJ Proc. Natl. Acad. Sci. 2013, 20912.

(2) Kim, YJ; Wu, W; Chun, S-E; Whitacre, JF; Bettinger, CJ Adv. Mater. 2014, 26, 6572.

(3) Kim, YJ; Chun, S-E; Whitacre, J; Bettinger, CJ J. Mater. Chem. B 2013, 1, 3781