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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UC Irvine Electronic Theses and Dissertations (2024)

Biology provides many sources of inspiration for synthetic and multi-functional nanomaterials. Naturally evolved proteins possess a range of unique functions and self-assembly behavior. Their flexible design, potential for stimuli responsiveness, and the ability for some proteins to undergo electron transport functions as part of metabolic processes make proteins ideal building blocks of bioelectronic interfaces. In biosensor and electrocatalysis applications, bioelectronic materials are designed to interconvert biological signals or processes into electronic signals and vice versa. Some examples of electronically conductive microbial protein materials motivate the use of peptides and proteins for responsive bioelectronic interfaces. In this work, we designed a peptide fiber structure that exhibits stimuli-responsive self-assembly and the capacity to transport electrical current over micrometer long distances. Hierarchically ordered nanofibers of α-helical coiled-coil peptides were assembled using a pH responsive structure ordering motif comprising of two neighboring lysine residues. Cryo-EM structures of these assemblies reveal a novel organization of α-helical peptides in a cross coiled coil arrangement that exhibits electrical conductivity. Both solid-state and solution-based electrochemical characterization show that these fibers are conductive. Single-fiber conductive AFM determined that the solid-state electrical conductivity is on a similar order of magnitude with conductive cytochrome filaments from bacteria. Solution deposited fiber films approximately doubled the electroactive surface area of the electrode, confirming their conductivity in aqueous environments. Furthermore, these fibers can be used as scaffolds for redox enzyme immobilization for electrochemical biosensing. Progress towards immobilized enzymatic devices will be discussed. This work further expands the field of stimuli-responsive and multifunctional nanomaterials by using peptide assemblies as structural supports for future implementation in bioelectronic and bioelectrochemical materials.

    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (2022)
    Fuel-driven dissipative self-assemblies play essential roles in living systems, contributing both to their complex, dynamic structures and emergent functions. Several dissipative supramolecular materials have been created using chemicals or light as fuel. However, electrical energy, one of the most common energy sources, has remained unexplored for such purposes. Here, we demonstrate a new platform for creating active supramolecular materials using electrically fueled dissipative self-assembly. Through an electrochemical redox reaction network, a transient and highly active supramolecular assembly is achieved with rapid kinetics, directionality, and precise spatiotemporal control. As electronic signals are the default information carriers in modern technology, the described approach offers a potential opportunity to integrate active materials into electronic devices for bioelectronic applications.
      Cover page: Electrically Fueled Active Supramolecular MaterialsCreative Commons 'BY' version 4.0 license
      • Article
      UC Irvine Previously Published Works (2021)
      Fuel-driven dissipative supramolecular assemblies in biology, such as actin filaments and microtubules contribute to the formation of complex, dynamic structures in living organisms and give rise to emergent functions such as motility, homeostasis, self-healing, and camouflage. Several synthetic dissipative supramolecular materials have been created using chemicals or light as fuel, with the goal of furthering our understanding of biological systems and creating synthetic materials that have life-like dynamic properties. However, electrical energy, one of the most common energy sources, has remained mostly unexplored for such purposes. Here we demonstrate the use of electrically fueled dissipative assembly as a new platform for creating active supramolecular materials. Through an electrochemical redox reaction network operating in mild aqueous buffers, a transient and highly active supramolecular assembly based on a redox-sensitive cysteine derivative is achieved by applying an electric potential. The dissipative self-assembly as well as its emergent properties can be spatiotemporally controlled by modulation of electrical signals on patterned microelectrodes. Using electrical energy as a readily available and clean fuel, we are able to create dissipative supramolecular materials rapidly (in seconds to minutes) and repetitively under mild conditions with directional and spatiotemporal control. As electronic signals are the default information carriers in modern technology, the described approach offers a promising opportunity to integrate active materials into electronic devices for bioelectronics applications.
        Cover page: Electrically fueled active supramolecular materialsCreative Commons 'BY' version 4.0 license
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