We gratefully acknowledge startup funds from Wayne State University (MJA), a grant from the American Foundation for Aging Research (SMV), and a Pathway to Independence Career Transition Award (R00EB007129) from the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health (MJA).

1. Metalation using LnCl3 salts
<ol>
	<li>Dissolve the ligand in water to produce a solution of 30-265 mM. The ligand 2-(4-isothiocyanatobenzyl)-diethylenetriamine pentaacetic acid 
	(p-SCN-Bn-DTPA) was used in this video at a concentration of 73 mM.</li>
	<li>Adjust the pH of the solution of ligand to between 5.5 and 7.0 by adding 1 M NH4OH. In this video, 0.2 mL of the 1 M NH4OH solution was used.</li>
	<li>Dissolve 1-2 equivalents of LnCl3 in water to produce a so...

<ol>
	<li>Barge, A., Cravotto, G., Gianolio, E., Fedeli, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=How+to+determine+free+Gd+and+free+ligand+in+solution+of+Gd+chelates.+A+technical+note.">How to determine free Gd and free ligand in solution of Gd chelates. A technical note.</a> Contrast Med. Mol. Imaging. 1, 184-188 (2006).</li><li>Nagaraja, T. N., Croxen, R. L., Panda, S., Knight, R. A., Keenan, K. A., Brown, S. L., Fenstermacher, J. D., Ewing, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+arsenazo+III+in+the+preparation+and+characterization+of+an+albumin-linked,+gadolinium-based+macromolecular+magnetic+resonance+contrast+agent.">Application of arsenazo III in the preparation and characterization of an albumin-linked, gadolinium-based macromolecular magnetic resonance contrast agent.</a> J. Neurosci. Methods. 157, 238-245 (2006).</li><li>Supkowski, R. M., Horrocks, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+determination+of+the+number+of+water+molecules,+q,+coordinated+to+europium(III)+ions+in+solution+from+luminescence+decay+lifetimes.">On the determination of the number of water molecules, q, coordinated to europium(III) ions in solution from luminescence decay lifetimes.</a> Inorg. Chim. Acta. 340, 44-48 (2002).</li><li>Menjoge, A. R., Kannan, R. M., Tomalia, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendrimer-based+drug+and+imaging+conjugates:+design+considerations+for+nanomedical+applications.">Dendrimer-based drug and imaging conjugates: design considerations for nanomedical applications.</a> Drug Discovery Today. 15, 171-185 (2010).</li><li>Que, E. L., Chang, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responsive+magnetic+resonance+imaging+contrast+agents+as+chemical+sensors+for+metals+in+biology+and+medicine.">Responsive magnetic resonance imaging contrast agents as chemical sensors for metals in biology and medicine.</a> Chem. Soc. Rev. 39, 51-60 (2010).</li><li>Uppal, R., Caravan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+probes+for+cardiovascular+MR+imaging.">Targeted probes for cardiovascular MR imaging.</a> Future Med. Chem. 2, 451-470 (2010).</li><li>Major, J. L., Meade, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioresponsive,+cell-penetrating,+and+multimeric+MR+contrast+agents.">Bioresponsive, cell-penetrating, and multimeric MR contrast agents.</a> Acc. Chem. Res. 42, 893-903 (2009).</li><li>Datta, A., Raymond, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gd-hydroxypyridinone+(HOPO)-based+high-relaxivity+magnetic+resonance+imaging+(MRI)+contrast+agents.">Gd-hydroxypyridinone (HOPO)-based high-relaxivity magnetic resonance imaging (MRI) contrast agents.</a> Acc. Chem. Res. 42, 938-947 (2009).</li><li>Le&#243;n-Rodr&#237;guez, L. M. D., Lubag, A. J. M., Malloy, C. R., Martinez, G. V., Gillies, R. J., Sherry, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responsive+MRI+agents+for+sensing+metabolism+in+vivo.">Responsive MRI agents for sensing metabolism in vivo.</a> Acc. Chem. Res. 42, 948-957 (2009).</li><li>Castelli, D. D., Gianolio, E., Crich, S. G., Terreno, E., Aime, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal+containing+nanosized+systems+for+MR-molecular+imaging+applications.">Metal containing nanosized systems for MR-molecular imaging applications.</a> Coord. Chem. Rev. 252, 2424-2443 (2008).</li><li>Caravan, P., Ellison, J. J., McMurry, T. J., Lauffer, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gadolinium(III)+chelates+as+MRI+contrast+agents:+structure,+dynamics,+and+applications.">Gadolinium(III) chelates as MRI contrast agents: structure, dynamics, and applications.</a> Chem. Rev. 99, 2293-2352 (1999).</li><li>Lauffer, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paramagnetic+metal+complexes+as+water+proton+relaxation+agents+for+NMR+imaging:+theory+and+design.">Paramagnetic metal complexes as water proton relaxation agents for NMR imaging: theory and design.</a> Chem. Rev. 87, 901-927 (1987).</li><li>Yoo, B., Pagel, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+responsive+MRI+contrast+agents+for+molecular+imaging.">An overview of responsive MRI contrast agents for molecular imaging.</a> Front. Biosci. 13, 1733-1752 (2008).</li><li>Pandya, S., Yu, J., Parker, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+emissive+europium+and+terbium+complexes+for+molecular+imaging+and+sensing.">Engineering emissive europium and terbium complexes for molecular imaging and sensing.</a> Dalton Trans. 23, 2757-2766 (2006).</li><li>Nwe, K., Xu, H., Regino, C. A. S., Bernardo, M., Ileva, L., Riffle, L., Wong, K. J., Brechbiel, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+approach+in+the+preparation+of+dendrimer-based+bifunctional+diethylenetriaminepentaacetic+acid+MR+contrast+agent+derivatives.">A new approach in the preparation of dendrimer-based bifunctional diethylenetriaminepentaacetic acid MR contrast agent derivatives.</a> Bioconjugate Chem. 20, 1412-1418 (2009).</li><li>Nwe, K., Bernardo, M., Regino, C. A. S., Williams, M., Brechbiel, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+MRI+properties+between+derivatized+DTPA+and+DOTA+gadolinium-dendrimer+conjugates.">Comparison of MRI properties between derivatized DTPA and DOTA gadolinium-dendrimer conjugates.</a> Bioorg. Med. Chem. 18, 5925-5931 (2010).</li><li>Caravan, P., Das, B., Deng, Q., Dumas, S., Jacques, V., Koerner, S. K., Kolodziej, A., Looby, R. J., Sun, W. -. C., Zhang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+lysine+walk+to+high+relaxivity+collagen-targeted+MRI+contrast+agents.">A lysine walk to high relaxivity collagen-targeted MRI contrast agents.</a> Chem. Commun. , 430-432 (2009).</li><li>Le&#243;n-Rodr&#237;guez, L. M. D., Kovacs, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+synthesis+and+chelation+chemistry+of+DOTA-peptide+conjugates.">The synthesis and chelation chemistry of DOTA-peptide conjugates.</a> Bioconjugate Chem. 19, 391-402 (2008).</li><li>Boswell, C. A., Eck, P. K., Regino, C. A. S., Bernardo, M., Wong, K. J., Milenic, D. E., Choyke, P. L., Brechbiel, M. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+characterization,+and+biological+evaluation+of+integrin+&#945;V&#946;3-targeted+PAMAM+dendrimers.">Synthesis, characterization, and biological evaluation of integrin &#945;V&#946;3-targeted PAMAM dendrimers.</a> Mol. Pharm. 5, 527-539 (2008).</li></ol>

Given the increasing number of publications that include lanthanide-based contrast agents4-14, it is important that care is taken in preparing, purifying, and characterizing products to ensure reproducible and comparable results. These complexes are often considered challenging to purify and characterize relative to organic molecules due to their paramagnetic nature and the sensitivity 
of any functional groups that could be used for bioconjugation. We have described common methods for the synthesis, purificat...

<table border="1">
 <tbody>
 <tr>
 <th>Reagents and Equipment</th>
 <th>Company</th>
 <th>Catalogue number</th>
 </tr>
 <tr>
 <td>EuCl3&bull;6H2O</td>
 <td>Sigma-Aldrich</td>
 <td>203254-5G</td>
 </tr>
 <tr>
 <td>p-SCN-Bn-DTPA</td>
 <td>Macrocyclics</td>
 <td>B-305</td>
 </tr>
 <tr>
 <td>ammonium hydroxide</td>
 <td>EMD</td>
 <td>AX1303-3</td>
 </tr>
 <tr>
 <td>Spectra/Por Biotech Cellulose Ester (CE) Dialysis Membrane - 500 D MWCO</td>
 <td>Fisher Scientific</td>
 <td>68-671-24</td>
 </tr>
 <tr>
 <td>Millipore IC Millex-LG Filter Units</td>
 <td>Fisher Scientific</td>
 <td>SLLG C13 NL</td>
 </tr>
 <tr>
 <td>xylenol orange tetrasodium salt</td>
 <td>Alfa Aesar</td>
 <td>41379</td>
 </tr>
 <tr>
 <td>acetic acid</td>
 <td>Fluka</td>
 <td>49199</td>
 </tr>
 <tr>
 <td>D2O</td>
 <td>Cambridge Isotope Laboratories, Inc.</td>
 <td>DLM-4-25</td>
 </tr>
 <tr>
 <td>water purifier</td>
 <td>ELGA</td>
 <td>Purelab Ultra</td>
 </tr>
 <tr>
 <td>high performance liquid chromatography and mass spectrometry</td>
 <td>Shimadzu</td>
 <td>LCMS-2010EV</td>
 </tr>
 <tr>
 <td>relaxation time analyzer</td>
 <td>Bruker</td>
 <td>mq60 minispec</td>
 </tr>
 <tr>
 <td>UV-vis spectrophotometer</td>
 <td>Fisher Scientific</td>
 <td>20-624-00092</td>
 </tr>
 <tr>
 <td>freeze dryer</td>
 <td>Fisher Scientific</td>
 <td>10-030-133</td>
 </tr>
 <tr>
 <td>pH meter</td>
 <td>Hanna Instruments</td>
 <td>HI 221</td>
 </tr>
 <tr>
 <td>spectrofluorometer</td>
 <td>HORIBA Jobin Yvon</td>
 <td>Fluoromax-4</td>
 </tr>
 <tr>
 <td>Molecular Weight Calculator version 6.46 by Matthew Monroe, downloaded October 17, 2009</td>
 <td><a href="http://ncrr.pnl.gov/software/">http://ncrr.pnl.gov/software/</a></td>
 <td>Molecular Weight Calculator</td>
 </tr>
 </tbody>
</table>

preparation, purification, and characterization of lanthanide complexes for use as contrast agents for magnetic resonance imaging

Polyaminopolycarboxylate-based ligands are commonly used to chelate lanthanide ions, and the resulting complexes are 
useful as contrast agents for magnetic resonance imaging (MRI). Many commercially available ligands are especially useful because they contain 
functional groups that allow for fast, high-purity, and high-yielding conjugation to macromolecules and biomolecules via amine-reactive 
activated esters and isothiocyanate groups or thiol-reactive maleimides. While metalation of these ligands is considered common 
knowledge in the field of bioconjugation chemistry, subtle differences in metalation procedures must be taken into account when 
selecting metal starting materials. Furthermore, multiple options for purification and characterization exist, and selection of the most 
effective procedure partially depends on the selection of starting materials. These subtle differences are often neglected in published 
protocols. Here, our goal is to demonstrate common methods for metalation, purification, and characterization of lanthanide complexes 
that can be used as contrast agents for MRI (Figure 1). We expect that this publication will enable biomedical scientists to incorporate 
lanthanide complexation reactions into their repertoire of commonly used reactions by easing the selection of starting materials and 
purification methods.

Watch this Scientific Journal Video about Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging at JoVE.com

Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging

We demonstrate the metalation, purification, and characterization of lanthanide complexes. The complexes described here can be conjugated to macromolecules to enable tracking of these molecules using magnetic resonance imaging.

Polyaminopolycarboxylate-based ligands are commonly used to chelate lanthanide ions, and the resulting complexes are 
useful as contrast agents for ...

preparation-purification-characterization-lanthanide-complexes-for

Research

JoVE Journal

Biology

14.9K vistas.  Wayne State University. Se demuestra la metalación, purificación y caracterización de los complejos de lantánidos. Los complejos descritos aquí pueden ser conjugados a las macromoléculas para permitir el seguimiento de estas moléculas por medio de resonancia magnética.