Self-Assembling Proteins for Bio-Inspired Nano-Electronics – BioNics

Bioelectronics is a fast growing research field aiming at mastering the interfacing of biological systems with electronic devices. Main envisioned applications are linked to medicine (e.g. biosensors for personalized healthcare) and environment survey (e.g. detection of pollutants). The challenge is to convert biological signals, mostly related to ligand binding and ion movements, into electrical signal that can be used by conventional electronic devices. BioNics is an attempt to prove the potential of amyloid fibers for the design and development of bioelectronic nanodevices. These self-assembled protein nanowires possess many advantages. 1) As biological macromolecules, they are likely to be biocompatible. 2) They result from the hierarchical self-assembly of proteins into high aspect-ratio fibers (diameter: 5 nm & length >10 mm) which can interact with biological targets. 3) They can be functionalized in a rationalized manner in many ways with biological macromolecules (other proteins, DNA, sugar…), or organic compounds, nanoparticles…. 4) They can support ionic, protonic, and electronic conductivity.

BioNics is set to tackle the long-range charge transport within amyloid fibers of known atomic structure. This will allow detailed interpretations of results and will open possibility for rationalized engineering. Two types of fibers will be studied: (1) “bare” amyloid fibers, called bare nanowires, in order to get insight into the intrinsic conductivity of amyloid fibers and (2) amyloid fibers functionalized with a redox domain, called RedOx nanowires, whose design is bioinspired from the architecture of microbial conductive filaments. The bare nanowires will be studied within dry conditions (dry films). The different conduction regimes and the different types of charge transport (electronic, ionic, protonic…) will be characterized from the macroscale (film) down to the nanoscale (single nanowires). A microelectronic test-vehicle will be specifically developed. This will allow also the first tentative of integration of protein nanowires into electronic devices, resulting in self-assembled protein nanowires-based FETs for instance. The RedOx nanowires more specifically aim at generating bioelectronic devices working in wet conditions within which the dominant conductivity mechanism is electron hopping between redox centers. This should enable electrochemically gated FETs sensitive to various ligands/substrates. In brief, BioNics will constitute a springboard for future enzyme logical circuits, protein-only biosensors and biofuel cells.

To the best of our knowledge, BioNics is the only consortium worldwide to have initiated so far such a radically innovative approach. This low TRL 1-3 collaborative project requires the cross-fertilizing association of the very different expertise of its 4 partners. The design of the protein nanowires requires expertise in protein engineering (LCBM). The multiscale (macro/meso/micro/nano-scopic scales) characterization of charge transport properties requires expertise on organic (semi)conductors and extended knowledge in charge transport mechanisms (SyMMES). Electronic measurements down to the single nanowires level and their integration into electronic devices require specific technological expertise as well as equipments and facilities only accessible in world class micro/nanotechnology centers (Leti). The development of electrodes for biosensors and biofuel cells requires expertise in interfacing electrodes made of different materials and in electrochemistry (DCM). Importantly, all partners are based in Grenoble which will be valuable for daily exchanges and interactions required for such an ambitious and multidisciplinary project.