0

Full Content is available to subscribers

Subscribe/Learn More  >

Synapse-Inspired Variable Conductance in Biomembranes: A Preliminary Study

[+] Author Affiliations
Joseph S. Najem, Graham J. Taylor

University of Tennessee - Oak Ridge National Laboratory, Oak Ridge, TN

Charles P. Collier

Oak Ridge National Laboratory, Oak Ridge, TN

Stephen A. Sarles

University of Tennessee, Knoxville, TN

Paper No. SMASIS2017-3820, pp. V001T08A005; 8 pages
doi:10.1115/SMASIS2017-3820
From:
  • ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems
  • Volume 1: Development and Characterization of Multifunctional Materials; Mechanics and Behavior of Active Materials; Bioinspired Smart Materials and Systems; Energy Harvesting; Emerging Technologies
  • Snowbird, Utah, USA, September 18–20, 2017
  • Conference Sponsors: Aerospace Division
  • ISBN: 978-0-7918-5825-7
  • Copyright © 2017 by ASME

abstract

Memristors are solid-state devices that exhibit voltage-controlled conductance. This tunable functionality enables the implementation of biologically-inspired synaptic functions in solid-state neuromorphic computing systems. However, while memristors are meant to emulate an intricate signal transduction process performed by soft biomolecular structures, they are commonly constructed from silicon- or polymer-based materials. As a result, the volatility, intricate design, and high-energy resistance switching in memristive devices, usually, leads to energy consumption in memristors that is several orders of magnitude higher than in natural synapses. Additionally, solid-state memristors fail to achieve the coupled dynamics and selectivity of synaptic ion exchange that are believed to be necessary for initiating both short- and long-term potentiation (STP and LTP) in neural synapses, as well as paired-pulse facilitation (PPF) in the presynaptic terminal. LTP is a phenomenon mostly responsible for driving synaptic learning and memory, features that enable signal transduction between neurons to be history-dependent and adaptable. In contrast, current memristive devices rely on engineered external programming parameters to imitate LTP. Because of these fundamental differences, we believe a biomolecular approach offers untapped potential for constructing synapse-like systems. Here, we report on a synthetic biomembrane system with biomolecule-regulated (alamethicin) variable ion conductance that emulates vital operational principals of biological synapse. The proposed system consists of a synthetic droplet interface bilayer (DIB) assembled at the conjoining interface of two monolayer-encased aqueous droplets in oil. The droplets contain voltage-activated alamethicin (Alm) peptides, capable of creating conductive pathways for ion transport through the impermeable lipid membrane. The insertion of the peptides and formation of transmembrane ion channels is achieved at externally applied potentials higher than ∼70 m V. Just like in biological synapses, where the incorporation of additional receptors is responsible for changing the synaptic weight (i.e. conductance), we demonstrate that the weight of our synaptic mimic may be changed by controlling the number of alamethicin ion channels created in a synthetic lipid membrane. More alamethicin peptides are incorporated by increasing the post-threshold external potential, thus leading to higher conductance levels for ion transport. The current-voltage responses of the alamethicin-based synapse also exhibit significant “pinched” hysteresis — a characteristic of memristors that is fundamental to mimicking synapse plasticity. We demonstrate the system’s capability of exhibiting STP/PPF behaviors in response to high-frequency 50 ms, 150 mV voltage pulses. We also present and discuss an analytical model for an alamethicin-based memristor, classifying that later as a “generic memristor”.

Copyright © 2017 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In