Name: fabrication procedures and birefringence measurements for designing magnetically responsive lanthanide ion chelating phospholipid assemblies
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The authors acknowledge the Swiss National Science Foundation for financing SMhardBi (project number 200021_150088/1). The SANS experiments were performed at the Swiss spallation neutron source SINQ, Paul Scherrer Instute, Villigen, Switzerland. The authors warmly thank Dr. Joachim Kohlbrecher for his guidance with the SANS experiments. The birefringence measurement setup under high magnetic fields was inspired from the existing setup at the high-field magnetic laboratory HFML, Nijmegen, The Netherlands. We thank Bruno Pfister for his help in developing the electronics of the birefringence setup, Jan Corsano and Daniel Kiechl for constructing the frameworks permitting fine and facile alignment of the laser, and Dr. Bernhard Koller for ongoing technical support.

1. Fabrication procedure for DMPC/DMPE-DTPA/Tm3+ (molar ratio 4:1:1) and DMPC/Chol-OH/DMPE-DTPA/Tm3+ (molar ratio 16:4:5:5) polymolecular assemblies
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	<li>Preliminary preparations
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		<li>Wash all the glassware by flushing once with ethanol stabilized chloroform (&#62;99% chloroform) and dry with compressed air.</li>
		<li>Produce 2 distinct 10 mg/mL stock solutions of DMPC and DMPE-DTPA in ethanol-stabilized chloroform (&#62;99% chloroform), a 10 mM stock solution of Chol-OH in ethanol-st...

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	<li>Sanders, C. R., Hare, B. J., Howard, K. P., Prestegard, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetically-oriented+phospholipid+micelles+as+a+tool+for+the+study+of+membrane-associated+molecules.">Magnetically-oriented phospholipid micelles as a tool for the study of membrane-associated molecules.</a> Prog. Nucl. Magn. Reson. Spectrosc. 26, 421-444 (1994).</li><li>Glover, K. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+evaluation+of+phospholipid+bicelles+for+solution-state+studies+of+membrane-associated+biomolecules.">Structural evaluation of phospholipid bicelles for solution-state studies of membrane-associated biomolecules.</a> Biophys. J. 81 (4), 2163-2171 (2001).</li><li>Katsaras, J. H. T. A., Pencer, J., Nieh, M. -. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term="Bicellar"+lipid+mixtures+as+used+in+biochemical+and+biophysical+studies.">"Bicellar" lipid mixtures as used in biochemical and biophysical studies.</a> Naturwissenschaften. 92 (8), 355-366 (2005).</li><li>Sanders, C. R., Prosser, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bicelles:+a+model+membrane+system+for+all+seasons?.">Bicelles: a model membrane system for all seasons?.</a> Structure. 6 (10), 1227-1234 (1998).</li><li>D&#252;rr, U. H. N., Soong, R., Ramamoorthy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=When+detergent+meets+bilayer:+birth+and+coming+of+age+of+lipid+bicelles.">When detergent meets bilayer: birth and coming of age of lipid bicelles.</a> Prog. Nucl. Magn. Reson. Spectrosc. 69, 1-22 (2013).</li><li>D&#252;rr, U. H. N., Gildenberg, M., Ramamoorthy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+magic+of+bicelles+lights+up+membrane+protein+structure.">The magic of bicelles lights up membrane protein structure.</a> Chem. 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Bicelle Preparation Available from: <a target="_blank" href="https://avantilipids.com/tech-support/liposome-preparation/bicelle-preparation">https://avantilipids.com/tech-support/liposome-preparation/bicelle-preparation</a> (2017)</li><li>Isabettini, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+Generating+Highly+Magnetically+Responsive+Lanthanide-Chelating+Phospholipid+Polymolecular+Assemblies.">Methods for Generating Highly Magnetically Responsive Lanthanide-Chelating Phospholipid Polymolecular Assemblies.</a> Langmuir. 33, 6363-6371 (2017).</li><li>Nieh, M. -. P., Glinka, C. J., Krueger, S., Prosser, R. 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V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+chelate-induced+magnetic+alignment+of+biological+membranes.">Novel chelate-induced magnetic alignment of biological membranes.</a> Biophys. J. 75, 2163-2169 (1998).</li><li>Shklyarevskiy, I. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+alignment+of+self-assembled+anthracene+organogel+fibers.">Magnetic alignment of self-assembled anthracene organogel fibers.</a> Langmuir. 21, 2108-2112 (2005).</li><li>Christianen, P. C. M., Shklyarevskiy, I. O., Boamfa, M. I., Maan, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alignment+of+molecular+materials+in+high+magnetic+fields.">Alignment of molecular materials in high magnetic fields.</a> Physica B: Condens. Matter. 346, 255-261 (2004).</li><li>Maret, G., Dransfeld, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biomolecules+and+polymers+in+high+steady+magnetic+fields.">Biomolecules and polymers in high steady magnetic fields.</a> Top. App. Phys. 57, 143-204 (1985).</li><li>Gielen, J. C., Shklyarevskiy, I. O., Schenning, A. P. H. J., Christianen, P. C. M., Maan, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+magnetic+birefringence+to+determine+the+molecular+arrangement+of+supramolecular+nanostructures.">Using magnetic birefringence to determine the molecular arrangement of supramolecular nanostructures.</a> Sci. Tech. Adv. Mater. 10 (1), 014601 (2009).</li><li>Shklyarevskiy, I. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Deformation and ordering of molecular assemblies in high magnetic fields. , (2005).</li><li>Fuller, G. 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A detailed account of how birefringence measurements were used in combination with SANS experiments to evaluate methods for generating highly magnetically responsive Ln3+ chelating phospholipids assemblies is in Isabettini et al.23 The proposed fabrication protocols are also applicable for assemblies composed of the longer DPPC and DPPE-DTPA phospholipids or for those containing chemically engineered steroid derivatives in their bilayer.11,<su...

Bicelles are disk-like polymolecular assemblies obtained from numerous lipid mixtures.1,2,3,4,5 They are widely used for the structural characterization of membrane biomolecules by NMR spectroscopy.6,7 However, recent efforts aim to expand the field of possible applications.5,8,9 The most studied bicelle system is composed of a mixture of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), constituting the planar part of the assembly, and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) phospholipid covering the edge.1,2,3 The molecular geometry of the phospholipids composing the bilayer dictate the architecture of the self-assembled polymolecular structure.4,5 Replacing DHPC with DMPE-DTPA generates highly magnetically responsive and tunable bicelle systems.10,11 DMPC/DMPE-DTPA/Ln3+ (molar ratio 4:1:1) bicelles associate with many more paramagnetic lanthanide ions (Ln3+) on the bilayer&#39;s surface, resulting in an enhanced magnetic response.10 Moreover, replacing the water-soluble DHPC molecules with DMPE-DTPA/Ln3+ enables the formation of dilution-resistant bicelles.11
The magnetic alignability of planar polymolecular assemblies is dictated by their overall magnetic energy,
<img alt="Equation 1" src="/files/ftp_upload/56812/56812eq1v2.jpg" /> (1)
where B is the magnetic field strength, <img alt="Equation 2" src="/files/ftp_upload/56812/56812eq2.jpg" /> the magnetic constant, n the aggregation number and <img alt="Equation 3" src="/files/ftp_upload/56812/56812eq3.jpg" /> the molecular diamagnetic susceptibility anisotropy of the lipids composing the bilayer. Therefore, the response of DMPC/DMPE-DTPA/Ln3+ bicelles to magnetic fields is tailored by their size (aggregate number n) and the molecular diamagnetic susceptibility anisotropy &#916;&#967;. The latter is readily achieved by changing the nature of the chelated Ln3+.12,13,14,15 Introducing cholesterol (Chol-OH) or other steroid derivatives in the bilayer offers the possibility of tuning both the aggregate number n and the magnetic susceptibility &#916;&#967; of the assemblies.11,16,17,18,19 For a given lipid composition, larger assemblies contain more lipids capable of contributing to the Emag (larger aggregate number n), resulting in more alignable species. The size of DMPC/DHPC bicelles, for example, is conventionally controlled through optimization of the composing lipid ratio or total concentration.20,21,22 Although this is possible in DMPC/DMPE-DTPA/Ln3+ bicelles, their thermo-reversible transformation from bicelle to vesicles upon heating offers added tailoring options. Mechanical means such as extrusion through membrane filters allows shaping of the vesicles. The magnetically alignable bicelles are regenerated upon cooling to 5 &#176;C and their dimensions are dictated from the vesicle precursors.11 Herein, we focus on the potential of mechanical fabrication procedures with DMPC/DMPE-DTPA/Tm3+ (molar ratio 4:1:1) or DMPC/Chol-OH/DMPE-DTPA/Tm3+ (molar ratio 16:4:5:5) as reference systems. The process works analogously when working with other Ln3+ than Tm3+. The wide range of possibilities offered by these techniques are highlighted in Figure 1 and extensively discussed elsewhere.23
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56812/56812fig1.jpg" /> 
Figure 1: Schematic overview of the possible fabrication procedures. The studied magnetically alignable Ln3+ chelating polymolecular assemblies are composed of either DMPC/DMPE-DTPA/Tm3+ (molar ratio 4:1:1) or DMPC/Chol-OH/DMPE-DTPA/Tm3+ (molar ratio 16:4:5:5). The dry lipid film is hydrated with a 50 mM phosphate buffer at a pH value of 7.4 and the total lipid concentration is 15 mM. An effective hydration of the lipid film requires either freeze thawing cycles (FT) or heating and cooling cycles (H&#38;C). H&#38;C cycles are necessary to regenerate samples after the last freeze thawing step, or to regenerate samples kept frozen over a prolonged period of time if they are to be used without further extrusion. These steps are extensively discussed by Isabettini et al.23 Maximally alignable polymolecular assemblies are achieved, delivering different assembly architectures based on the lipid composition. The bicelle size and magnetic alignability is tunable by extrusion (Ext) through nanopore membrane filters. The presented alignment factors Af were computed from 2D small angle neutron scattering (SANS) patterns of a DMPC/Chol-OH/DMPE-DTPA/Tm3+ (molar ratio 16:4:5:5) sample extruded through either 800, 400, 200, or 100 nm pores. SANS measurements are a complementary means of quantifying bicelle alignment that will not be covered in more detail herein.11,16 The Af ranges from -1 (parallel neutron scattering or perpendicular alignment of the bicelles with respect to the magnetic field direction) to 0 for isotropic scattering. <a href="//cloudflare.jove.com/files/ftp_upload/56812/56812fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The structure of bicelles has been extensively studied by a wide range of characterization techniques.13 The alignment of bicelles exposed to a magnetic field has been quantified by using either NMR spectroscopy or small angle neutron scattering (SANS) experiments.5,10,11,12,13,16,17,18,19,24,25 However, the shift and broadening of the NMR peaks occurring in the presence of Ln3+ are serious limitations to the method.15,26,27,28 Although SANS experiments do not suffer from this limitation, alternative and more accessible techniques are desirable for routine quantification of magnetically induced alignment of assemblies in solution. Birefringence measurements are a viable and comparatively simple alternative. Analogously to NMR experiments, birefringence measurements reveal valuable information on lipid rearrangements and lipid phases occurring in the bilayer. Moreover, geometric transformations occurring in the polymolecular assembly with changing environmental conditions such as temperature are monitored.11,12,13,16 Magnetically induced birefringence &#916;n&#8242; has been used to study various types of phospholipid systems.13,29,30 Birefringence measurements based on the phase modulation technique in a magnetic field is a viable method to detect orientation of bicelles.12,16,18,29,31,32 The possibility of investigating bicelles with birefringence in high magnetic fields up to 35 T was also demonstrated by M. Liebi et al.13
When polarized light enters an anisotropic material, it will be refracted in an ordinary and extraordinary wave.11 The two waves have different velocities and are shifted in phase by a retardation &#948;. The degree of retardation &#948; is measured and converted into a birefringence signal&#160;<img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" /> to quantify the degree of anisotropy in the material using
<img alt="Equation 6" src="/files/ftp_upload/56812/56812eq6.jpg" /> (2)
where &#955; is the wavelength of the laser and d is the thickness of the sample. Phospholipids are optically anisotropic and their optical axis coincides with their long molecular axes, parallel to the hydrocarbon tails.11,12 No retardation is measured if the phospholipids are randomly orientated in solution. Retardation is measured when phospholipids are aligned parallel to each other. The magnetically induced birefringence&#160;<img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" /> can have a positive or negative sign depending on the orientation of the molecules in the magnetic field; see Figure 2. Phospholipids aligned parallel to the x-axis will result in a negative <img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" />, while those aligned along the z-axis result in a positive <img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" />. No birefringence is observed when the optical axis coincides with the direction of light propagation as the phospholipid aligns parallel to the y-axis.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56812/56812fig2.jpg" /> 
Figure 2: Alignment of the phospholipids and corresponding sign of the magnetically induced birefringence <img alt="Equation 12" src="/files/ftp_upload/56812/56812eq12.jpg" />. The sign of the measured <img alt="Equation 12" src="/files/ftp_upload/56812/56812eq12.jpg" /> depends on the orientation of the phospholipid in the magnetic field. Dashed lines indicate the optical axis of the molecule. The light is polarized at 45&#176; and propagates in the y direction. The magnetic field B is in the z direction. This figure has been modified from M. Liebi.11 <a href="//cloudflare.jove.com/files/ftp_upload/56812/56812fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the case of an isotropic colloidal suspension of bicelles, the orientation induced by the arrangement of the phospholipids in the bilayer will be lost, zeroing the retardation &#948;. The bicelles must also align in order to orientate the optically active phospholipids in their bilayers, causing a retardation &#948; of the polarized light. Consequently, birefringence is a sensitive tool to quantify the magnetic alignability of polymolecular assemblies. Bicelles aligned perpendicular to the magnetic field will yield a positive <img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" />, while those aligned parallel will yield a negative <img alt="Equation 5" src="/files/ftp_upload/56812/56812eq5.jpg" />. The sign depends on the alignment of the setup and may be checked with a reference sample.

<table>
	<tbody>
		<tr>
			<td>1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)</td>
			<td>Avanti Polar Lipids</td>
			<td>850345P</td>
			<td>&#62;99%</td>
		</tr>
		<tr>
			<td>1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate acid hexammonium salt (DMPE-DTPA)</td>
			<td>Avanti Polar Lipids</td>
			<td>790535P</td>
			<td>&#62;99%</td>
		</tr>
		<tr>
			<td>Thulium(III) chloride</td>
			<td>Sigma-Aldrich</td>
			<td>439649</td>
			<td>anhydrous, powder, 99.9% trace metals basis</td>
		</tr>
		<tr>
			<td>Dysprosium(III) chloride</td>
			<td>Sigma-Aldrich</td>
			<td>325546</td>
			<td>anhydrous, powder, 99.9% trace metals basis</td>
		</tr>
		<tr>
			<td>Ytterbium(III) chloride</td>
			<td>Sigma-Aldrich</td>
			<td>439614</td>
			<td>anhydrous, powder, 99.9% trace metals basis</td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Sigma-Aldrich</td>
			<td>319988</td>
			<td>contains ethanol as stabilizer, ACS reagent, &#8805;99.8%</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Aldrich</td>
			<td>34860</td>
			<td>&#8805;99.9%</td>
		</tr>
		<tr>
			<td>Cholesterol</td>
			<td>Amresco</td>
			<td>433</td>
			<td>Ultra pure grade</td>
		</tr>
		<tr>
			<td>D2O</td>
			<td>ARMAR chemicals</td>
			<td>1410</td>
			<td>99.8 atom % D</td>
		</tr>
		<tr>
			<td>Ultrapure water</td>
			<td>Millipore</td>
			<td></td>
			<td>Synergy pak2 (SYPK0SIX2), Millipack GP (MPGP02001)</td>
		</tr>
		<tr>
			<td>electronic pH meter</td>
			<td>Metrohm</td>
			<td>17440010</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatmann Nuclepore 25 mm 100nm membrane filter</td>
			<td>VWR</td>
			<td>515-2028</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatmann Nuclepore 25 mm 200nm membrane filter</td>
			<td>VWR</td>
			<td>515-2029</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatmann Nuclepore 25 mm 400nm membrane filter</td>
			<td>VWR</td>
			<td>515-2030</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatmann Nuclepore 25 mm 800nm membrane filter</td>
			<td>VWR</td>
			<td>515-2032</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatmann Filter paper</td>
			<td>VWR</td>
			<td>230600</td>
			<td></td>
		</tr>
		<tr>
			<td>25 ml round bottom flask</td>
			<td>VWR</td>
			<td>201-1352</td>
			<td>14/23 NS</td>
		</tr>
		<tr>
			<td>3 ml glass snap-cup</td>
			<td>VWR</td>
			<td>548-0554</td>
			<td>ND18, 18x30mm</td>
		</tr>
		<tr>
			<td>2.5 ml glass syringe</td>
			<td>Hamilton</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dihydrogen phosphate dihydrate</td>
			<td>Merk</td>
			<td>1.06342</td>
			<td>Salt used to make phosphate buffer</td>
		</tr>
		<tr>
			<td>di-Sodium hydrogen phosphate</td>
			<td>Merk</td>
			<td>1.06586</td>
			<td>Salt used to make phosphate buffer</td>
		</tr>
		<tr>
			<td>Liquid Nitrogen</td>
			<td>Carbagas</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Pressurized Nitrogen gas</td>
			<td>Carbagas</td>
			<td>-</td>
			<td>200 bar bottle</td>
		</tr>
		<tr>
			<td>Lipid Extruder 10 ml</td>
			<td>Lipex</td>
			<td>-</td>
			<td>Fully equipped with thermobarrel</td>
		</tr>
		<tr>
			<td>High-pressure PVC tube</td>
			<td>GR NETUM</td>
			<td>-</td>
			<td>must resist more than 4 MPa</td>
		</tr>
		<tr>
			<td>Serto adaptors</td>
			<td>Sertot</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrile gloves</td>
			<td>VWR</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>2 ml glass pipettes</td>
			<td>VWR</td>
			<td>612-1702</td>
			<td>230 mm long</td>
		</tr>
		<tr>
			<td>Diode Laser</td>
			<td>Newport</td>
			<td>LPM635-25C</td>
			<td></td>
		</tr>
		<tr>
			<td>DSP Dual Phase Lock-in Amplifier</td>
			<td>SRS</td>
			<td>SR830</td>
			<td></td>
		</tr>
		<tr>
			<td>Photodiode Detector</td>
			<td>Silonex Inc.</td>
			<td>SLSD-71N5</td>
			<td>5mm2, Silicon, photo-conductive</td>
		</tr>
		<tr>
			<td>5.5 T Cryogenic Magnetic</td>
			<td>Cryogenic/Oerlikon AG</td>
			<td>-</td>
			<td>12 bar He-cooled. RW4000/6000 compressor, RGD 5/100 TA cryo-head</td>
		</tr>
		<tr>
			<td>Second order low pass filter</td>
			<td>home-built</td>
			<td>-</td>
			<td>Linear power supply 24V DC, second order, Sallen Key, cut-off frequency 360 Hz, +/- 12V, max 10 mA</td>
		</tr>
		<tr>
			<td>Photoelastic modulator</td>
			<td>Hinds instruments</td>
			<td>PEM-90</td>
			<td></td>
		</tr>
		<tr>
			<td>Glan-Thompson Calcite Polarizer</td>
			<td>Newport</td>
			<td>10GT04</td>
			<td>25.4mm diameter</td>
		</tr>
		<tr>
			<td>Quartz sample cuvette</td>
			<td>Hellma</td>
			<td>165-10-40</td>
			<td>temperature controlled cell, 0.8 ml, 10mm path length</td>
		</tr>
		<tr>
			<td>Temperature probe</td>
			<td>Thermocontrol</td>
			<td>-</td>
			<td>Type K, 0.5mm diameter, Thermocoax</td>
		</tr>
		<tr>
			<td>Non-polarizing mirrors</td>
			<td>Newport</td>
			<td>50326-1002</td>
			<td>25.4mm</td>
		</tr>
		<tr>
			<td>RS 232 cables</td>
			<td>National Instruments</td>
			<td>189284-02</td>
			<td>For Connecting to the RS-232 Port on the front of Compact FieldPoint Controllers</td>
		</tr>
		<tr>
			<td>BNC 50 &#937; cable and connectors</td>
			<td>National Instruments</td>
			<td>763389-01</td>
			<td></td>
		</tr>
		<tr>
			<td>cFP-AI-110</td>
			<td>National Instruments</td>
			<td>777318-110</td>
			<td>8-Channel Analog Voltage and Current Input Module for Compact FieldPoint</td>
		</tr>
		<tr>
			<td>cFP-CB-1</td>
			<td>National Instruments</td>
			<td>778618-01</td>
			<td>Integrated Connector Block for Wiring to Compact FieldPoint I/O</td>
		</tr>
		<tr>
			<td>cFP-CB-3</td>
			<td>National Instruments</td>
			<td>778618-03</td>
			<td>Integrated Isothermal Connector Block for Wiring Thermocouples to the cFP-TC-120 Module</td>
		</tr>
		<tr>
			<td>cFP-TC-120</td>
			<td>National Instruments</td>
			<td>777318-120</td>
			<td>8-Channel Thermocouple Input Module for Compact FieldPoint</td>
		</tr>
		<tr>
			<td>cFP-1804</td>
			<td>National Instruments</td>
			<td>779490-01</td>
			<td>Ethernet/Serial Interface for NI Compact FieldPoint</td>
		</tr>
		<tr>
			<td>LabView 2010</td>
			<td>National Instruments</td>
			<td>-</td>
			<td></td>
		</tr>
		<tr>
			<td>Industrial power supply</td>
			<td>Traco Power</td>
			<td>TCL 060-124</td>
			<td>100-240V AC</td>
		</tr>
		<tr>
			<td>Waterbath</td>
			<td>Julabo</td>
			<td>FP40-HE</td>
			<td>refrigerated/Heating Circulator</td>
		</tr>
	</tbody>
</table>

fabrication procedures and birefringence measurements for designing magnetically responsive lanthanide ion chelating phospholipid assemblies

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural studies by nuclear magnetic resonance (NMR) to nanotechnological developments including the formation of optically active and magnetically switchable gels. Such technologies require high control of the assembly size, magnetic response and thermal resistance. Mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and its lanthanide ion (Ln3+) chelating phospholipid conjugate, 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA), assemble into highly magnetically responsive assemblies such as DMPC/DMPE-DTPA/Ln3+ (molar ratio 4:1:1) bicelles. Introduction of cholesterol (Chol-OH) and steroid derivatives in the bilayer results in another set of assemblies offering unique physico-chemical properties. For a given lipid composition, the magnetic alignability is proportional to the bicelle size. The complexation of Ln3+ results in unprecedented magnetic responses in terms of both magnitude and alignment direction. The thermo-reversible collapse of the disk-like structures into vesicles upon heating allows tailoring of the assemblies&#39; dimensions by extrusion through membrane filters with defined pore sizes. The magnetically alignable bicelles are regenerated by cooling to 5 &#176;C, resulting in assembly dimensions defined by the vesicle precursors. Herein, this fabrication procedure is explained and the magnetic alignability of the assemblies is quantified by birefringence measurements under a 5.5 T magnetic field. The birefringence signal, originating from the phospholipid bilayer, further enables monitoring of polymolecular changes occurring in the bilayer. This simple technique is complementary to NMR experiments that are commonly employed to characterize bicelles.

The birefringence signal of a non-extruded DMPC/DMPE-DTPA/Tm3+ (molar ratio 4:1:1) sample was monitored under a 5.5 T magnetic field during a heating and cooling cycle from 5 to 40 &#176;C and back at a rate of 1 &#176;C/min (Figure 6). The birefringence results confirmed high magnetic alignments at 5 &#176;C with a value of 1.5 x 10-5, twice as strong as for the reported extruded systems.6,<sup class="...

Watch this Scientific Journal Video about Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies at JoVE.com

Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies

Fabrication procedures for highly magnetically responsive lanthanide ion chelating polymolecular assemblies are presented. The magnetic response is dictated by the assembly size, which is tailored by extrusion through nanopore membranes. The assemblies&#39; magnetic alignability and temperature-induced structural changes are monitored by birefringence measurements, a complimentary technique to nuclear magnetic resonance and small angle neutron scattering.

Bicelles are tunable disk-like polymolecular assemblies formed from a large variety of lipid mixtures. Applications range from membrane protein structural ...

The overall goal of this procedure is to fabricate highly magnetically responsive lanthanide ion chelating polymolecular assemblies, and to easily monitor the magnetic response with birefringence measurements. Birefringence measurements can help answer key questions in the design of magnetically responsive polymolecular assemblies, such as bicelles, by providing an alternative and comparatively easy means of monitoring alignment. The main advantage of this polymolecular assemblies is the ability to deliver an unrefined and tunable magnetic response at field strength as low as one or two tesla by associating with numbers per magnetic lanthanide ions.Although monitoring of the birefringence seeker provides important information for the bicelles design, it can also actually apply to the study of other magnetically responsive systems, such as neuro crystalline sedolos or amyloid fibers doped with iron oxide nanoparticles. To begin the procedure, use a 2.5 milliliter glass syringe and three milliliter snap cap vials to measure the needed quantities of DMPC, DMPE-DTPA, Cholesterol, and Thulium(III)chloride stock solutions. Combine the stock solutions in a 25 milliliter round bottom flask.Rinse each vial into the flask with 2.5 milliliter of the solvent used in the corresponding stock solution. Clamp the flask on a rotary evaporator. Remove solvent from the mixture at 40 degrees Celsius under 30, 000 Pascals, until only a viscous transparent film remains.Reduce the pressure to 100 Pascals and continue drawing the sample for a minimum of two hours to obtain a dry lipid film. Then, flush the flask with argon for one minute. Seal the flask with paraffin film and store the sample at 18 degrees Celsius.When ready to rehydrate the lipid, add three milliliter of 15 millimolar pH 7.4 phosphate buffer to the flask. Rotate the flask in a liquid nitrogen bath until the sample is thoroughly frozen, as indicated by the liquid nitrogen no longer boiling. Then, rotate the flask for 5 minutes in a water bath set to 60 degrees Celsius.Once the sample is completely liquid, vortex the sample for 30 seconds. After the last freezing step, stabilize the sample with two heating-cooling cycles. First, obtain track-etched polycarbonate membrane filters with the desired pore size for the extrusion.Begin assembling a 10 milliliter lipid extruder with a jacketed sample vessel, aided by silicone-tipped tweezers. Use a few drops of phosphate buffer to wet the support mesh and the polyester drain disk for optimal placement of the membrane filter. Carefully lay the O-ring on the membrane filter.Ensure that there are no folds or creases on the membrane. Finish assembling the lipid extruder and connect the jacketed sample vessel to a temperature controlled water circulator. Heat the circulator water bath to 60 degrees Celsius and start circulation.Connect the extruder to a pressurized nitrogen gas bottle using high-pressure PVC tubing and quick-connect fittings. Set the extrusion pressure to the appropriate value for the membrane pore size. Use a two milliliter glass pipette to add the sample to the jacketed vessel.Close the vessel and allow the sample to equilibrate for 30 to 60 seconds. Place the end of the sample outlet tube in the sample flask. Then, open the flow of nitrogen to the extruder while holding the sample outlet tube steady.Once sample extrusion has finished, vent the extruder and use the same two milliliter glass pipette to transfer the extruded sample to the jacketed vessel. Perform 10 extrusion cycles in this way. Replacing the membrane filter whenever it begins to clog.Repeat the extrusion through smaller pore sizes as desired. Turn on and set up the birefringence measurement apparatus. Then, place the sample in a temperature-controlled quartz cuvette with a 10 millimeter path length.Connect the cuvette to an external water bath set to five degrees Celsius. Insert a 0.5 millimeter thick k-type thermocouple into the sample through an aperture in the cap. Adjust the water bath temperature based on the thermocouple reading until the sample reaches five degrees Celsius.Place the cuvette in the bore of the magnet. Verify that the thermocouple is not in the laser path by holding a sheet of paper in the laser path beyond the cuvette and looking for shadows cast by the thermocouple. It is important to monitor the sample's temperature directly but the probe must not be in the way of the laser light.This is readily checked with the white paper placed in the laser path after the cuvette and looking for shadows. Apply a steady flow of room-temperature dry compressed air at 10, 000 Pascals to the cuvette, to avoid the formation of condensation. Select the amplifier sensitivity multipliers, ensuring that the amplifier is not overloaded, and no more than four red bars appear on the display.Next, autofaze both lock-in amplifiers. The sample's turbidity may change dramatically during a temperature cycle due to polymolecular rearrangements. The highest turbidity usually occurs at low temperatures and to avoid a signal overload upon heating, the sensitivity must not be set too high at five degrees Celsius.Fill in the sample name and the lock-in amplifier sensitivities. Enter a file name for the measurement and start logging the data. Then, ramp the magnetic field to 5.5 Teslas using the measurement program.Acquire birefringence signal data at various sample temperatures and magnetic field strengths as desired. The birefringence signal of cholesterol doped bicelles extruded through membranes with 800 nanometer pores increased with increasing magnetic field strength, with peak birefringence achieved at 5.5 Teslas. Successive extrusions at 60 degrees Celsius through membranes with decreasing pore sizes resulted in decreasing birefringence values at five degrees Celsius.A reduction in absolute alignment factor was also observed. These results indicated that magnetic alignment could be tuned by adjusting the bicelle sizes by extrusion of their vesicle precursors. Once mastered, this technique can be done on a daily basis to effectively screen many samples and identify the most promising candidates, delivering an optimal magnetic rease bonds of the required temperature range.Following the successful identification of the most promising sample with this procedure, are the methods like small angle neutron scattering or cryo transmission electron microscopy can be performed to answer additional questions about the structure of the physical chemical properties of the assemblies. When working with lipid assemblies, such as the bicelles presented herein, it is important to work with clean glassware in a calm environment. We recommend dedicating glassware for this work and washing with chloroform.

fabrication-procedures-birefringence-measurements-for-designing

Research

JoVE Journal

Engineering

Construction and Testing of Coin Cells of Lithium Ion Batteries

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime. Lithium ion batteries have also been considered to be used in electric and hybrid vehicles1 or even electrical grid stabilization systems2. All these applications simulate a dramatic increase in the research and development of battery materials3-7, including new materials3,8, doping9, nanostructuring10-13, coatings or surface modifications14-17 and novel binders18. Consequently, an increasing number of physicists, chemists and materials scientists have recently ventured into this area. Coin cells are widely used in research laboratories to test new battery materials; even for the research and development that target large-scale and high-power applications, small coin cells are often used to test the capacities and rate capabilities of new materials in the initial stage. 
 In 2010, we started a National Science Foundation (NSF) sponsored research project to investigate the surface adsorption and disordering in battery materials (grant no. DMR-1006515). In the initial stage of this project, we have struggled to learn the techniques of assembling and testing coin cells, which cannot be achieved without numerous help of other researchers in other universities (through frequent calls, email exchanges and two site visits). Thus, we feel that it is beneficial to document, by both text and video, a protocol of assembling and testing a coin cell, which will help other new researchers in this field. This effort represents the "Broader Impact" activities of our NSF project, and it will also help to educate and inspire students.
In this video article, we document a protocol to assemble a CR2032 coin cell with a LiCoO2 working electrode, a Li counter electrode, and (the mostly commonly used) polyvinylidene fluoride (PVDF) binder. To ensure new learners to readily repeat the protocol, we keep the protocol as specific and explicit as we can. However, it is important to note that in specific research and development work, many parameters adopted here can be varied. First, one can make coin cells of different sizes and test the working electrode against a counter electrode other than Li. Second, the amounts of C black and binder added into the working electrodes are often varied to suit the particular purpose of research; for example, large amounts of C black or even inert powder were added to the working electrode to test the "intrinsic" performance of cathode materials14. Third, better binders (other than PVDF) have also developed and used18. Finally, other types of electrolytes (instead of LiPF6) can also be used; in fact, certain high-voltage electrode materials will require the uses of special electrolytes7.

A protocol to construct and test coin cells of lithium ion batteries is described. The specific procedures of making a working electrode, preparing a counter electrode, assembling a cell inside a glovebox and testing the cell are presented.

Rechargeable lithium ion batteries have wide applications in electronics, where customers always demand more capacity and longer lifetime.  Lithium ion ...

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries Using Synchrotron Radiation Techniques

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. During insertion or removal of alkali metal ions, the redox states of transition metals in the compounds change and structural transformations such as phase transitions and/or lattice parameter increases or decreases occur. These behaviors in turn determine important characteristics of the batteries such as the potential profiles, rate capabilities, and cycle lives. The extremely bright and tunable x-rays produced by synchrotron radiation allow rapid acquisition of high-resolution data that provide information about these processes. Transformations in the bulk materials, such as phase transitions, can be directly observed using X-ray diffraction (XRD), while X-ray absorption spectroscopy (XAS) gives information about the local electronic and geometric structures (e.g.&#160;changes in redox states and bond lengths). In situ experiments carried out on operating cells are particularly useful because they allow direct correlation between the electrochemical and structural properties of the materials. These experiments are time-consuming and can be challenging to design due to the reactivity and air-sensitivity of the alkali metal anodes used in the half-cell configurations, and/or the possibility of signal interference from other cell components and hardware. For these reasons, it is appropriate to carry out ex situ experiments (e.g.&#160;on electrodes harvested from partially charged or cycled cells) in some cases. Here, we present detailed protocols for the preparation of both ex situ and in situ samples for experiments involving synchrotron radiation and demonstrate how these experiments are done.

We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li-ion and Na-ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices

Intercalation compounds such as transition metal oxides or phosphates are the most commonly used electrode materials in Li-ion and Na-ion batteries. ...

Speciation and Bioavailability Measurements of Environmental Plutonium Using Diffusion in Thin Films

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can potentially contribute to the exposure of biota and humans. The diffusive gradients in thin films technique is introduced here for in-situ measurements of Pu bioavailability and speciation. A diffusion cell constructed for laboratory experiments with Pu and the newly developed protocol make it possible to simulate the environmental behavior of Pu in model solutions of various chemical compositions. Adjustment of the oxidation states to Pu(IV) and Pu(V) described in this protocol is essential in order to investigate the complex redox chemistry of plutonium in the environment. The calibration of this technique and the results obtained in the laboratory experiments enable to develop a specific DGT device for in-situ Pu measurements in freshwaters. Accelerator-based mass-spectrometry measurements of Pu accumulated by DGTs in a karst spring allowed determining the bioavailability of Pu in a mineral freshwater environment. Application of this protocol for Pu measurements using DGT devices has a large potential to improve our understanding of the speciation and the biological transfer of Pu in aquatic ecosystems.

The technique of diffusive gradients in thin films (DGT) is proposed for speciation studies of plutonium. This protocol describes diffusion experiments probing the behavior of Pu(IV) and Pu(V) in presence of organic matter. DGTs deployed in a karstic spring allow assessment of the bioavailability of Pu.

The biological uptake of plutonium (Pu) in aquatic ecosystems is of particular concern since it is an alpha-particle emitter with long half-life which can ...

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed. In this study, molybdenum diselenide (MoSe2) layer crystals with a thickness range of 6-2,700 nm were fabricated as two- or four-terminal devices. Ohmic contact formation was successfully achieved by the focused-ion beam (FIB) deposition method using platinum (Pt) as a contact metal. Layer crystals with various thicknesses were prepared through simple mechanical exfoliation by using dicing tape. Current-voltage curve measurements were performed to determine the conductivity value of the layer nanocrystals. In addition, high-resolution transmission electron microscopy, selected-area electron diffractometry, and energy-dispersive X-ray spectroscopy were used to characterize the interface of the metal&#8211;semiconductor contact of the FIB-fabricated MoSe2 devices. After applying the approaches, the substantial thickness-dependent electrical conductivity in a wide thickness range for the MoSe2-layer semiconductor was observed. The conductivity increased by over two orders of magnitude from 4.6 to 1,500 &#937;&#8722;1 cm&#8722;1, with a decrease in the thickness from 2,700 to 6 nm. In addition, the temperature-dependent conductivity indicated that the thin MoSe2 multilayers exhibited considerably weak semiconducting behavior with activation energies of 3.5-8.5 meV, which are considerably smaller than those (36-38 meV) of the bulk. Probable surface-dominant transport properties and the presence of a high surface electron concentration in MoSe2 are proposed. Similar results can be obtained for other layer semiconductor materials such as MoS2 and WS2.

We describe the approaches for the device fabrication and electrical characterization of molybdenum diselenide (MoSe2) layer semiconductor nanostructures with different thicknesses. In addition, the fabrication of ohmic contacts for MoSe2-layer nanocrystals by the focused-ion beam deposition method using platinum (Pt) as a contact metal is described.

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor ...

Synthesis and Functionalization of 3D Nano-graphene Materials: Graphene Aerogels and Graphene Macro Assemblies

Efforts to assemble graphene into three-dimensional monolithic structures have been hampered by the high cost and poor processability of graphene. Additionally, most reported graphene assemblies are held together through physical interactions (e.g., van der Waals forces) rather than chemical bonds, which limit their mechanical strength and conductivity. This video method details recently developed strategies to fabricate mass-producible, graphene-based bulk materials derived from either polymer foams or single layer graphene oxide. These materials consist primarily of individual graphene sheets connected through covalently bound carbon linkers. They maintain the favorable properties of graphene such as high surface area and high electrical and thermal conductivity, combined with tunable pore morphology and exceptional mechanical strength and elasticity. This flexible synthetic method can be extended to the fabrication of polymer/carbon nanotube (CNT) and polymer/graphene oxide (GO) composite materials. Furthermore, additional post-synthetic functionalization with anthraquinone is described, which enables a dramatic increase in charge storage performance in supercapacitor applications.

This video method describes the synthesis of high surface area, monolithic 3D graphene-based materials derived from polymer precursors as well as single layer graphene oxide.

Efforts to assemble graphene into three-dimensional monolithic structures have been hampered by the high cost and poor processability of graphene. ...

Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature

The chemical instability of the traditional electrolyte remains a safety issue in widely used energy storage devices such as Li-ion batteries. Li-ion batteries for use in devices operating at elevated temperatures require thermally stable and non-flammable electrolytes. Ionic liquids (ILs), which are non-flammable, non-volatile, thermally stable molten salts, are an ideal replacement for flammable and low boiling point organic solvent electrolytes currently used today. We herein describe the procedures to: 1) synthesize mono- and di-phosphonium ionic liquids paired with chloride or bis(trifluoromethane)sulfonimide (TFSI) anions; 2) measure the thermal properties and stability of these ionic liquids by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA); 3) measure the electrochemical properties of the ionic liquids by cyclic voltammetry (CV); 4) prepare electrolytes containing lithium bis(trifluoromethane)sulfonamide; 5) measure the conductivity of the electrolytes as a function of temperature; 6) assemble a coin cell battery with two of the electrolytes along with a Li metal anode and LiCoO2 cathode; and 7) evaluate battery performance at 100 &#176;C. We additionally describe the challenges in execution as well as the insights gained from performing these experiments.

Here, we describe protocols to prepare phosphonium-based ionic liquid and lithium bis(trifluoromethane)sulfonimide salt electrolytes, and assemble a non-flammable and high temperature functioning lithium-ion coin cell battery.

The chemical instability of the traditional electrolyte remains a safety issue in widely used energy storage devices such as Li-ion batteries. Li-ion ...

Magnetically Induced Rotating Rayleigh-Taylor Instability

Classical techniques for investigating the Rayleigh-Taylor instability include using compressed gasses1, rocketry2 or linear electric motors3 to reverse the effective direction of gravity, and accelerate the lighter fluid toward the denser fluid. Other authorse.g. 4,5,6 have separated a gravitationally unstable stratification with a barrier that is removed to initiate the flow. However, the parabolic initial interface in the case of a rotating stratification imposes significant technical difficulties experimentally. We wish to be able to spin-up the stratification into solid-body rotation and only then initiate the flow in order to investigate the effects of rotation upon the Rayleigh-Taylor instability. The approach we have adopted here is to use the magnetic field of a superconducting magnet to manipulate the effective weight of the two liquids to initiate the flow. We create a gravitationally stable two-layer stratification using standard flotation techniques. The upper layer is less dense than the lower layer and so the system is Rayleigh-Taylor stable. This stratification is then spun-up until both layers are in solid-body rotation and a parabolic interface is observed. These experiments use fluids with low magnetic susceptibility, |&#967;| ~ 10-6 - 10-5, compared to a ferrofluids. The dominant effect of the magnetic field applies a body-force to each layer changing the effective weight. The upper layer is weakly paramagnetic while the lower layer is weakly diamagnetic. When the magnetic field is applied, the lower layer is repelled from the magnet while the upper layer is attracted towards the magnet. A Rayleigh-Taylor instability is achieved with application of a high gradient magnetic field. We further observed that increasing the dynamic viscosity of the fluid in each layer, increases the length-scale of the instability.

We present a protocol for preparing a two-layer density-stratified liquid that can be spun-up into solid body rotation and subsequently induced into Rayleigh-Taylor instability by applying a gradient magnetic field.

Classical techniques for investigating the Rayleigh-Taylor instability include using compressed gasses1, rocketry2 or linear electric motors3 to reverse ...

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of lithium-ion (Li-ion) batteries. However, a number of setbacks prevent their integration into commercial devices. The main limiting factor is due to nanoscale phenomena occurring at the electrode/electrolyte interfaces, ultimately leading to degradation of battery operation. These key problems are highly challenging to observe and characterize as these batteries contain multiple buried interfaces. One approach for direct observation of interfacial phenomena in thin film batteries is through the fabrication of electrochemically active nanobatteries by a focused ion beam (FIB). As such, a reliable technique to fabricate nanobatteries was developed and demonstrated in recent work. Herein, a detailed protocol with a step-by-step process is presented to enable the reproduction of this nanobattery fabrication process. In particular, this technique was applied to a thin film battery consisting of LiCoO2/LiPON/a-Si, and has further been previously demonstrated by in situ cycling within a transmission electron microscope.

Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing

A protocol for the fabrication of electrochemically active LiPON-based solid-state lithium-ion nanobatteries using a focused ion beam is presented.

Solid-state electrolytes are a promising replacement for current organic liquid electrolytes, enabling higher energy densities and improved safety of ...

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due to their potential applications for future device technologies such as sensors and storage. However, conventional approaches, which usually utilize materials containing magnetic metal ions (or radicals), have a major problem: only a few materials have been found to show the coupling phenomena at room temperature. Recently, we proposed a new approach to achieve room-temperature magnetoelectrics. In contrast to conventional approaches, our alternative proposal focuses on a completely different material, a &#34;liquid crystal&#34;, free from magnetic metal ions. In such liquid crystals, a magnetic field can be utilized to control the orientational state of constituent molecules and the corresponding electric polarization through magnetic anisotropy of the molecules; it is an unprecedented mechanism of the magnetoelectric effect. In this context, this paper provides a protocol to measure ferroelectric properties induced by a magnetic field, that is, the direct magnetoelectric effect, in a liquid crystal. With the method detailed here, we successfully detected magnetically-tuned electric polarization in the chiral smectic C phase of a liquid crystal at room temperature. Taken together with the flexibility of constituent molecules, which directly affects the magnetoelectric responses, the introduced method will serve to allow liquid crystal cells to acquire more functions as room-temperature magnetoelectrics and associated optical materials.

In this report, we present a protocol to examine direct magnetoelectric effects, i.e., induction of ferroelectric polarization by applying magnetic fields, in liquid crystals. This protocol provides a unique approach, supported by the softness of liquid crystals, to achieve room-temperature magnetoelectrics.

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...