Name: assembly and characterization of biomolecular memristors consisting of ion channel-doped lipid membranes
Uploaded: 2019-03-09T15:00:00
Description: Watch this Scientific Journal Video about Assembly and Characterization of Biomolecular Memristors Consisting of Ion Channel-doped Lipid Membranes at JoVE.com

Financial support was provided by the National Science Foundation Grant NSF ECCS-1631472. Research for G.J.T., C.D.S., A.B., and C.P.C. was partially sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.&#160;

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This paper presents a protocol for assembling and characterizing biomolecular memristors based on ion channel-doped synthetic biomembranes formed between two droplets of water in oil. The soft-matter, two-terminal device is designed and studied to: 1) overcome constraints that are associated with solid-state technology, such as high noise, high energy consumption, and high switching voltages, 2) more closely mimic the composition, structure, switching mechanisms of biological synapses, and 3) explore the mechanisms and f...

It is widely recognized that biological synapses are responsible for the high efficiency and enormous parallelism of the brain due to their ability to learn and process information in highly adaptive ways. This coordinated functionality emerges from multiple, highly complex molecular mechanisms that drive both short-term and long-term synaptic plasticity1,2,3,4,5. Neuromorphic computing systems aim to emulate synaptic functionalities at levels approaching the density, complexity, and energy efficiency of the brain, which are needed for the next generation of brain-like computers6,7,8. However, reproducing synaptic features using traditional electronic circuit elements is virtually impossible9, instead requiring the design and fabrication of new hardware elements that can adapt to incoming signals and remember information histories9. These types of synapse-inspired hardware are known as mem-elements9,10,11 (short for memory elements), which, according to Di Ventra et al.9,11, are passive, two-terminal devices whose resistance, capacitance, or inductance can be reconfigured in response to external stimuli, and which can remember prior states11. To achieve energy consumption levels approaching those in the brain, these elements should employ similar materials and mechanisms for synaptic plasticity12.
To date, two-terminal memristors13,14,15 have predominantly been built using complementary metal-oxide-semiconductor (CMOS) technology, characterized by high-switching voltages and high noise. This technology does not scale well due to high power consumption and low density. To address these limitations, multiple organic and polymeric memristors have been recently built. However, these devices exhibit significantly slower switching dynamics due to time-consuming ion diffusion through a conductive polymer matrix16,17. As a result, the mechanisms by which both CMOS-based and organic memristive devices emulate synapse-inspired functionalities are highly phenomenological, encompassing only a few synaptic functionalities such as Spike Timing Dependent Plasticity (STDP)18, while overlooking other key features that also play essential roles in making the brain a powerful and efficient computer, such as pre-synaptic, short-term plasticity19.&#160;
Recently, we introduced a new class of memristive devices12 featuring voltage-activated peptides incorporated in biomimetic lipid membranes that mimics the biomolecular composition, membrane structure, and ion channel triggered switching mechanisms of biological synapses20.&#160; Here, we describe how to assemble and electrically interrogate these two-terminal devices, with specific focus on how to evaluate short-term plasticity for implementation in online learning applications12. Device assembly is based on the droplet interface bilayer (DIB)21 method, which has been used extensively in recent years to study the biophysics of model membranes21 and membrane-bound ion channels22,23,24, and as building blocks for the development of stimuli-responsive materials25,26. We describe the membrane assembly and interrogation process in detail for those interested in neuromorphic applications but have limited experience in biomaterials or membrane biology. The protocol also includes a full description of the characterization procedure, which is as important as the assembly process, given the dynamic and reconfigurable electrical properties of the device27. The procedure and representative results described here are foundations for a new class of low-cost, low-power, soft mem-elements based on lipid interfaces and other biomolecules for applications in neuromorphic computing, autonomous structures and systems, and even adaptive brain-computer interfaces.

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			<td style="width:183px;">850356P/850356C</td>
			<td style="width:663px;">Purchased as lyophilized powder (P) or in chloroform (C)&#160;</td>
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			<td style="width:183px;">610000</td>
			<td>This includes a mini-extruder, 2 syringes, 100 PC membranes, 100 filter supports, and 1 holder/heating block</td>
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assembly and characterization of biomolecular memristors consisting of ion channel-doped lipid membranes

The ability to recreate synaptic functionalities in synthetic circuit elements is essential for neuromorphic computing systems that seek to emulate the cognitive powers of the brain with comparable efficiency and density. To date, silicon-based three-terminal transistors and two-terminal memristors have been widely used in neuromorphic circuits, in large part due to their ability to co-locate information processing and memory. Yet these devices cannot achieve the interconnectivity and complexity of the brain because they are power-hungry, fail to mimic key synaptic functionalities, and suffer from high noise and high switching voltages. To overcome these limitations, we have developed and characterized a biomolecular memristor that mimics the composition, structure, and switching characteristics of biological synapses. Here, we describe the process of assembling and characterizing biomolecular memristors consisting of a 5 nm-thick lipid bilayer formed between lipid-functionalized water droplets in oil and doped with voltage-activated alamethicin peptides. While similar assembly protocols have been used to investigate biophysical properties of droplet-supported lipid membranes and membrane-bound ion channels, this article focuses on key modifications of the droplet interface bilayer method essential for achieving consistent memristor performance. Specifically, we describe the liposome preparation process and the incorporation of alamethicin peptides in lipid bilayer membranes, and the appropriate concentrations of each constituent as well as their impact on the overall response of the memristors. We also detail the characterization process of biomolecular memristors, including measurement and analysis of memristive current-voltage relationships obtained via cyclic voltammetry, as well as short-term plasticity and learning in response to step-wise voltage pulse trains.

Figure 1 displays the experimental setup used to assemble and characterize the biomolecular memristor. Lowering the free ends of the electrodes to the bottom of the oil reservoir, as shown in Figure 1b, was found helpful to minimize vibrations of the electrodes and droplets that can result in variations in measured current and bilayer area, especially in cases where heating the oil can generate convective flow in the oil. Figure 2 s...

Watch this Scientific Journal Video about Assembly and Characterization of Biomolecular Memristors Consisting of Ion Channel-doped Lipid Membranes at JoVE.com

Assembly and Characterization of Biomolecular Memristors Consisting of Ion Channel-doped Lipid Membranes

Soft, low-power, biomolecular memristors leverage similar composition, structure, and switching mechanisms of bio-synapses. Presented here is a protocol to assemble and characterize biomolecular memristors obtained from insulating lipid bilayers formed between water droplets in oil. The incorporation of voltage-activated alamethicin peptides results in memristive ionic conductance across the membrane.

The ability to recreate synaptic functionalities in synthetic circuit elements is essential for neuromorphic computing systems that seek to emulate the ...

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Biomolecular Detection employing the Interferometric Reflectance Imaging Sensor (IRIS)

Biomolecular Detection employing the Interferometric Reflectance Imaging Sensor IRIS

Interferometric 반사율 이미징 센서 (IRIS)를 채용 Biomolecular 감지

The sensitive measurement of biomolecular interactions has use in many fields and industries such as basic biology and microbiology, ...

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Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry

Monolayer의 합성, 조립, 그리고 특성화는 단백질 Monolayer의 전기에 대한 골드 Nanoparticle 필름을 보호

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently ...

Isolation of Cellular Lipid Droplets: Two Purification Techniques Starting from Yeast Cells and Human Placentas

세포 지질 방울의 분리 : 효모 세포와 인간의 태반에서 시작 두 정화 기술

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Isolation and Characterization Of Chimeric Human Fc-expressing Proteins Using Protein A Membrane Adsorbers And A Streamlined Workflow

단백질 A 멤브레인 흡착제 및 간소화된 워크플로우를 사용하여 키메라 인간 Fc 발현 단백질의 격리 및 특성화

Laboratory scale to industrial scale purification of biomolecules from cell culture supernatants and lysed cell solutions can be accomplished using ...

Micropatterning and Assembly of 3D Microvessels

미세화 및 3D 미세 혈관의 조립

In vitro platforms to study endothelial cells and vascular biology are largely limited to 2D endothelial cell culture, flow chambers with polymer or glass ...

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone

나란히 이온 교환 멤브레인 사이의 이온 농도 분극을 병합하면 편광 영역의 전파를 차단하는

The ion concentration polarization (ICP) phenomenon is one of the most prevailing methods to preconcentrate low-abundance biological samples. The ICP ...

A Method for Growing Bio-memristors from Slime Mold

바이오-memristors 점액 금형에서 성장 하는 방법

Our research is aimed at gaining a better understanding of the electronic properties of organisms in order to engineer novel bioelectronic systems and ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

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나노 제형에도 Limulus Amoebocyte Lysate (LAL) 분석 실험을 사용 하 여

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Growth and Characterization of Irradiated Organoids from Mammary Glands

유 방 땀 샘에서 조사 된 유기 체의 성장과 특성화

Organoids derived from the digested tissue are multicellular three-dimensional (3D) constructs that better recapitulate in vivo conditions than cell ...

Focused Ion Beam Lithography to Etch Nano-architectures into Microelectrodes

마이크로 전극에 에칭 나노 아키텍처에 초점을 맞춘 이온 빔 리소그래피

With advances in electronics and fabrication technology, intracortical microelectrodes have undergone substantial improvements enabling the production of ...