This work was supported in part by the NIH grants R01 EB008101 and R01 CA103830.

1. Instrumentations and Glassware Preparation
<ol>
	<li>Wear appropriate protective equipment, i.e., a lab coat, disposable gloves, and eye protection.</li>
	<li>Connect a round-bottom flask to a condenser and immerse it in a silicone oil bath with a temperature monitoring by a thermometer. Place a source of heat (e.g., hot plate) under the oil bath (Figure 1). Use a thermometer capable of measuring the temperature higher than 260 &#176;C.</li>
</ol>
2. Synthesis...

<ol>
	<li>Bigall, N. C., Parak, W. J., Dorfs, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent,+magnetic+and+plasmonic&#8212;Hybrid+multifunctional+colloidal+nano+objects.">Fluorescent, magnetic and plasmonic&#8212;Hybrid multifunctional colloidal nano objects.</a> Nano Today. 7, 282-296 (2012).</li><li>Gautier, J., Allard-Vannier, E., Herve-Aubert, K., Souce, M., Chourpa, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+strategies+of+hybrid+metallic+nanoparticles+for+theragnostic+applications.">Design strategies of hybrid metallic nanoparticles for theragnostic applications.</a> Nanotechnology. 24, 432002 (2013).</li><li>Wei, Q., Wei, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optical+imaging+with+dynamic+contrast+agents.">Optical imaging with dynamic contrast agents.</a> Chemistry. 17, 1080-1091 (2011).</li><li>Aaron, J. 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=Increased+optical+contrast+in+imaging+of+epidermal+growth+factor+receptor+using+magnetically+actuated+hybrid+gold/iron+oxide+nanoparticles.">Increased optical contrast in imaging of epidermal growth factor receptor using magnetically actuated hybrid gold/iron oxide nanoparticles.</a> Optics express. 14, 12930-12943 (2006).</li><li>Song, H. -. M., Wei, Q., Ong, Q. K., Wei, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plasmon-resonant+nanoparticles+and+nanostars+with+magnetic+cores:+synthesis+and+magnetomotive+imaging.">Plasmon-resonant nanoparticles and nanostars with magnetic cores: synthesis and magnetomotive imaging.</a> ACS nano. 4, 5163-5173 (2010).</li><li>Qu, M., 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=Magneto-photo-acoustic+imaging.">Magneto-photo-acoustic imaging.</a> Biomedical optics express. 2, 385-396 (2011).</li><li>Jin, Y., Jia, C., Huang, S. -. W., Donnell O&amp;39, M., Gao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multifunctional+nanoparticles+as+coupled+contrast+agents.">Multifunctional nanoparticles as coupled contrast agents.</a> Nature communications. 1, 41 (2010).</li><li>Wu, C. -. H., 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=Versatile+Immunomagnetic+Nanocarrier+Platform+for+Capturing+Cancer+Cells.">Versatile Immunomagnetic Nanocarrier Platform for Capturing Cancer Cells.</a> ACS. 7, 8816-8823 (2013).</li><li>Galanzha, E. I., 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=In+vivo+magnetic+enrichment+and+multiplex+photoacoustic+detection+of+circulating+tumour+cells.">In vivo magnetic enrichment and multiplex photoacoustic detection of circulating tumour cells.</a> Nature nanotechnology. 4, 855-860 (2009).</li><li>Larson, T. A., Bankson, J., Aaron, J., Sokolov, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybrid+plasmonic+magnetic+nanoparticles+as+molecular+specific+agents+for+MRI/optical+imaging+and+photothermal+therapy+of+cancer+cells.">Hybrid plasmonic magnetic nanoparticles as molecular specific agents for MRI/optical imaging and photothermal therapy of cancer cells.</a> Nanotechnology. 18, 325101 (2007).</li><li>Yu, H., 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=Dumbbell-like+bifunctional+Au-Fe3O4+nanoparticles.">Dumbbell-like bifunctional Au-Fe3O4 nanoparticles.</a> Nano letters. 5, 379-382 (2005).</li><li>Wang, L., 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=Monodispersed+core-shell+Fe3O4@Au+nanoparticles.">Monodispersed core-shell Fe3O4@Au nanoparticles.</a> The journal of physical chemistry. B. 109, 21593-21601 (2005).</li><li>Wang, H., Brandl, D. W., Le, F., Nordlander, P., Halas, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanorice:+a+hybrid+plasmonic+nanostructure.">Nanorice: a hybrid plasmonic nanostructure.</a> Nano letters. 6, 827-832 (2006).</li><li>Hu, X., 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=Trapping+and+Photoacoustic+Detection+of+CTCs+at+the+Single+Cell+per+Milliliter+Level+with+Magneto&#8208;Optical+Coupled+Nanoparticles.">Trapping and Photoacoustic Detection of CTCs at the Single Cell per Milliliter Level with Magneto&#8208;Optical Coupled Nanoparticles.</a> Small. 9, 2046-2052 (2013).</li><li>Truby, R. L., Emelianov, S. Y., Homan, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ligand-mediated+self-assembly+of+hybrid+plasmonic+and+superparamagnetic+nanostructures.">Ligand-mediated self-assembly of hybrid plasmonic and superparamagnetic nanostructures.</a> Langmuir. 29, 2465-2470 (2013).</li><li>Bai, F., 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=A+Versatile+Bottom&#8208;up+Assembly+Approach+to+Colloidal+Spheres+from+Nanocrystals.">A Versatile Bottom&#8208;up Assembly Approach to Colloidal Spheres from Nanocrystals.</a> Angewandte Chemie International Edition. 46, 6650-6653 (2007).</li></ol>

Critical steps in successful synthesis of magneto-plasmonic nanoclusters include making highly monodispersed primary gold shell/iron oxide core nanoparticles and directing self-assembly of the primary particles into nanoclusters. A molar ratio between the primary particles and surfactants play an important role in determining size distribution of the nanoclusters. Non-uniform size distribution of primary nanoparticles may cause formation of big aggregates during assembly of magneto-plasmonic nanoclusters. In addition, th...

Hybrid nanoparticles consisting of different materials with distinct physicochemical properties can open new opportunities in biomedical applications including multimodal molecular imaging, therapy delivery and monitoring, new screening and diagnostic assays1-3. The combination of plasmonic and magnetic properties in a single nanoparticle is of particular interest because it provides a very strong light scattering and absorption cross-sections associated with plasmon resonances and&#160;responsiveness to a magnetic field. For example, magneto-plasmonic nanoparticles were used to increase contrast in dark-field imaging of labeled cells by applying a temporal signal modulation via an external electromagnet3-5. More recently, a similar principle was applied in development of a new imaging modality &#8211; magneto-photoacoustic imaging, where magneto-plasmonic nanoparticles enable great improvements in&#160;contrast and signal-to-background ratio6,7. It was also shown that the hybrid nanoparticles can be used for simultaneous capture and detection of circulating tumor cells in whole blood and in vivo8,9.&#160;Furthermore, magneto-plasmonic nanoparticles are promising theranostic agents which can be used for molecular specific optical and MR imaging combined with photothermal therapy of cancer cells10.
Several approaches were explored for synthesis of magneto-plasmonic nanoparticles. For example, Yu et al. utilized decomposition and oxidation of Fe(CO)5 on&#160;gold nanoparticles to form dumbbell-like bifunctional Au&#8211;Fe3O4 nanoparticles11. Wang et al. have synthesized gold-coated iron oxide nanoparticle by using thermal decomposition method12. Some other approaches rely on coating polymer or amine functional molecules onto magnetic core nanoparticles followed by deposition of a gold shell onto the polymer surface to create the hybrid particles7,13. In addition, iron-oxide nanoparticles were attached to gold nanorods via electrostatic interactions or a chemical reaction14,15. Although these approaches yield magneto-plasmonic nanostructures, they compromise to some extent properties of the magneto-plasmonic combination such as optical absorbance in the near-infrared (NIR) window or a strong magnetic moment both of which are highly desirable in biomedical applications. For example,&#160;dumbbell Au-Fe3O4 nanoparticles have a plasmon resonance peak at 520 nm which limits their utility in vivo due to high tissue turbidity in this spectral range. Furthermore, the magneto-plasmonic nanoparticles produced by&#160;current protocols are limited to just one11 or few (less than 10)14,15 superparamagnetic moieties (e.g., iron oxide nanoparticles) that is significantly less than could be achieved in a densely packed nanostructure. For example, a densely packed 60 nm diameter spherical nanoparticle can contain on the order of a thousand of 6 nm superparamagnetic nanoparticles. Therefore, there is a great room for improving magnetic properties of the hybrid nanoparticles. Moreover, some of the previously described protocols are relatively complex and require careful optimization in order to avoid particle aggregation during synthesis14,15.
Here, we describe a protocol for synthesis of magneto-plasmonic nanoparticles with a strong magnetic moment and a strong NIR absorbance that addresses major limitations of the current art. The synthesis has its origins in oil-in-water microemulsion method16. It is based on assembly of nanoparticles of a desired size from a much smaller primary particles. This approach has been successfully used to produce nanostructures from a single material such as gold, iron oxide, and semiconductor primary particles16. We extended it to synthesis of magneto-plasmonic nanoparticles by, first, making 6 nm diameter gold shell/iron oxide core particles and, then, assembling the primary hybrid particles into the final spherical nanostructure. Assembling primary particles into nanoclusters not only allows enhancing the properties of constituent nanoparticles, such as achieving a stronger magnetic moment while preserving superparamagnetic properties, but also takes advantage of the interactions between individual nanoparticles thus&#160;creating&#160;new characteristics absent from the constituent nanoparticles, such as strong optical absorbance in the NIR window. This protocol yields hybrid nanoparticles with a high density of magnetic and plasmonic functionalities. After primary particles are synthetized, our method is essentially a simple one-pot reaction. The overall plasmon resonance strength and magnetic moment are determined by a&#160;number of primary particles and, therefore, can be easily optimized depending on an application. Furthermore, we also developed a procedure for antibody conjugation to the hybrid nanoparticles for various biomedical applications which require molecular specific targeting. Antibodies are attached through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

<table border="0" cellpadding="0" cellspacing="0" width="738">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Name of Material/ Equipment</td>
			<td style="width:101px;">Company</td>
			<td style="width:139px;">Catalog Number</td>
			<td style="width:247px;">Comments/Description</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:253px;">PYREX 50mL Round Bottom Boiling Flask with Short Neck &#38; 24/40 [ST] Joint</td>
			<td>Corning</td>
			<td style="width:139px;">4320A-50</td>
			<td>Thermal decomposition reaction</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:253px;">PYREX 41 x 300mm 5-Bulb Allihn Condenser with 24/40 [ST] Outer/Inner Joints</td>
			<td>Corning</td>
			<td style="width:139px;">2480-300</td>
			<td>Thermal decomposition reaction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Silicone Oil</td>
			<td>Fisher</td>
			<td style="width:139px;">S159-500</td>
			<td>Oil bath</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Hot Plate Stirrer</td>
			<td>Corning</td>
			<td style="width:139px;">PC-351</td>
			<td>Heat the reacton with stirring function</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Thermometer</td>
			<td>ThermoWorks</td>
			<td style="width:139px;">221-092</td>
			<td>Measure temperature</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:253px;">Iron (III) Acetylacetonate</td>
			<td>Fisher</td>
			<td style="width:139px;">AC11913-0250</td>
			<td rowspan="7" style="width:247px;">Materials for primary hybrid nanoparticles synthesis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Oleic Acid 99%</td>
			<td>Fisher</td>
			<td style="width:139px;">A195-500</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Gold (III) Acetate</td>
			<td>Fisher</td>
			<td style="width:139px;">AA3974206</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Hexane</td>
			<td>Fisher</td>
			<td style="width:139px;">H292-1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Phenyl Ether 99%</td>
			<td>Fisher</td>
			<td style="width:139px;">AC13060-0025</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1,2-Hexadecanediol 90%</td>
			<td>Sigma</td>
			<td style="width:139px;">213748-50G</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Oleylamine 70%</td>
			<td>Sigma</td>
			<td style="width:139px;">O7805-100G</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Sodium Dodecyl Sulfate</td>
			<td style="width:101px;">Fisher</td>
			<td style="width:139px;">BP166-100</td>
			<td rowspan="2" style="width:247px;">Cluster synthesis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Sodium Citrate Dihydrate</td>
			<td style="width:101px;">Sigma</td>
			<td style="width:139px;">W302600</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:253px;">Monoclonal Anti-EGF Receptor Antibody</td>
			<td style="width:101px;">Sigma</td>
			<td style="width:139px;">E2156</td>
			<td style="width:247px;">Cell labeling specificity test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Monoclonal Anti-HER2 Antibody</td>
			<td style="width:101px;">Sigma</td>
			<td style="width:139px;">AMAB90627</td>
			<td style="width:247px;">Cell labeling specificity test</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Sodium Periodate</td>
			<td style="width:101px;">Sigma</td>
			<td style="width:139px;">311448</td>
			<td style="width:247px;">Oxidate Fc region of antibodies</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:253px;">Dithiolaromatic PEG6-CONHNH2</td>
			<td style="width:101px;">SensoPath Technologies</td>
			<td style="width:139px;">SPT-0014B</td>
			<td style="width:247px;">Heterofunctional linker for antibody conjugation to nanoclusters</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:253px;">Methoxy-PEG-thiol, 5k</td>
			<td style="width:101px;">Creative PEGworks</td>
			<td style="width:139px;">PLS-604</td>
			<td style="width:247px;">Passivate the remaining gold surface after antibody conjugation</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:253px;">Amicon Ultra-4 Centrifugal Filter Unit with Ultracel-10 membrane</td>
			<td style="width:101px;">Millipore</td>
			<td style="width:139px;">UFC801008</td>
			<td style="width:247px;">Protien purification</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">HEPES</td>
			<td style="width:101px;">Sigma</td>
			<td style="width:139px;">H3375</td>
			<td style="width:247px;">Buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">PBS, 1X Solution</td>
			<td style="width:101px;">Fisher</td>
			<td style="width:139px;">BP2438-20</td>
			<td style="width:247px;">Buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">UV&#8722;vis Spectroscopy</td>
			<td style="width:101px;">BioTek&#160;</td>
			<td style="width:139px;">Synergy HT</td>
			<td style="width:247px;">Obtain spectrum</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td>Separation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Transmission Electron Microscope</td>
			<td>FEI</td>
			<td>TECNAI G2 F20 X-TWIN</td>
			<td>Obtain morphology of nanostructures</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Upright microscope</td>
			<td>Leica</td>
			<td>DM6000</td>
			<td>Obtain dark-field images</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sonicator</td>
			<td>Branson</td>
			<td>1510</td>
			<td>Sonication</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">Carbon Film 300 Mesh Grid</td>
			<td>EMS</td>
			<td style="width:139px;">CF300-Cu</td>
			<td>TEM imaging</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:253px;">96-well Plate</td>
			<td>Corning</td>
			<td style="width:139px;">09-761-145</td>
			<td>UV-vis reading plate</td>
		</tr>
	</tbody>
</table>

synthesis of immunotargeted magneto-plasmonic nanoclusters

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications including contrast enhancement in novel magnetomotive imaging modalities, simultaneous capture&#160;and detection of circulating tumor cells (CTCs),&#160;and multimodal molecular imaging combined with photothermal therapy of cancer cells. These applications have stimulated significant interest in development of protocols for synthesis of magneto-plasmonic nanoparticles with optical absorbance in the near-infrared (NIR) region and a strong magnetic moment. Here, we present a novel protocol for synthesis of such hybrid nanoparticles that is based on an oil-in-water microemulsion method. The unique feature of the protocol described herein is synthesis of magneto-plasmonic nanoparticles of various sizes from primary blocks which also have magneto-plasmonic characteristics. This approach yields nanoparticles with a high density of magnetic and plasmonic functionalities which are uniformly distributed throughout the nanoparticle volume. The hybrid nanoparticles can be easily functionalized by attaching antibodies through the Fc moiety leaving the Fab portion that is responsible for antigen binding available for targeting.

A scheme for synthesis of immunotargeted magneto-plasmonic nanoclusters is shown in Figure 2. First, magnetic Fe3O4 iron oxide nanoparticles are synthetized via thermal decomposition method. Then, a thin ca. 1 nm gold shell is deposited on the iron oxide core particles via thermal decomposition. The primary ca. 6 nm hybrid nanoparticles serve as seeds to create magneto-plasmonic nanoclusters by utilizing an oil-in-water microemulsion approach. The nanoclusters are ...

Watch this Scientific Journal Video about Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters at JoVE.com

Synthesis of Immunotargeted Magneto-plasmonic Nanoclusters

Here, we describe a protocol for synthesis of magneto-plasmonic nanoparticles with a strong magnetic moment and a strong near-infrared (NIR) absorbance. The protocol also includes antibody conjugation to the nanoparticles through the Fc moiety for various biomedical applications which require molecular specific targeting.

Magnetic and plasmonic properties combined in a single nanoparticle provide a synergy that is advantageous in a number of biomedical applications ...

synthesis-of-immunotargeted-magneto-plasmonic-nanoclusters

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Chemistry

15.1K vistas.  University of Texas at Austin.  Aquí se describe un protocolo para la síntesis de nanopartículas magneto-plasmónica con un fuerte momento magnético y un fuerte en el infrarrojo cercano (NIR) absorbancia. El protocolo también incluye conjugación de anticuerpos a las nanopartículas a través de la fracción Fc para diversas aplicaciones biomédicas que requieren orientación específica molecular. 