The financial support of the Max-Planck Society, the Turkish Ministry of National Education (PhD fellowship to S. G.), and the German Exchange Academic Service (DAAD, PhD fellowship to T. S.) are gratefully acknowledged.

<ol>
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The authors have nothing to disclose.

Herstellung der dendrimeren MRI Kontrastmittels erfordert eine geeignete Auswahl der monomeren Einheit (dh der Chelator für Gd (III)). Sie reduzieren die Toxizität dieses paramagnetischen Ion und bis heute eine große Auswahl an azyklisch und makrocyclischen Chelatbildnern diesem Zweck dienen 1-3. Unter diesen makrocyclischen DOTA-Typ - Chelatoren besitzen die höchste Stabilität thermodynamischen und kinetischen Inertheit und damit sind die bevorzugte Wahl zur Herstellung von inerten MRI - Kontra...

Die Magnetresonanztomographie (MRT) ist ein leistungsfähiges und nichtionisierende Bildgebungstechnik weit verbreitet in der biomedizinischen Forschung und der klinischen Diagnostik aufgrund seiner nicht-invasiven Natur und ausgezeichnete Eigenweichteilkontrast. Die am häufigsten verwendeten MRI Verfahren verwenden das Signal von Wasserprotonen erhalten wird, Bilder mit hoher Auflösung und die Bereitstellung detaillierter Informationen innerhalb der von Unterschieden in der Dichte der Wassersignale basierend Geweben. Die Signalintensität und die Spezifität der MRI-Experimente weiter verbessert werden kann unter Verwendung von Kontrastmitteln (CAs). Diese sind paramagnetische oder super Spezies , die die longitudinale (T 1) und Querrichtung (T 2) Relaxationszeiten beeinflussen bzw. 1,2. Komplexe der Lanthanid - Ion Gadolinium mit Polyaminogruppen Polycarbonsäure Liganden sind die am häufigsten verwendeten T 1 CAs. Gadolinium (III) verkürzt die T 1 EntspannungsZeit von Wasserprotonen zu erhöhen, so dass die Signalkontrast in der MRT - Experimente 3. Jedoch ionische Gadolinium ist giftig; dessen Größe etwa derjenigen von Calcium (II), und es wirkt sich stark Calcium-assisted in Zellen signalisieren. Daher Chelate azyklisch und makrocyclischen werden verwendet, um diese Toxizität zu neutralisieren. Verschiedene mehrzähnigen Liganden wurden bisher 1, was zu Gadolinium (III) -Komplexe mit hoher thermodynamischer Stabilität und kinetische Inertheit entwickelt. Diejenigen, auf der Basis der 12-glied azamacrocycle cyclen, insbesondere seine Tetra Derivat DOTA (1,4,7,10-Tetraazacyclododecan-1,4,7,10-tetraacetate) sind die am besten untersuchten und angewandte Komplexe dieser CA-Klasse. Dennoch GdDOTA-Typ CAs sind niedermolekulare Systeme und zeigt gewisse Nachteile wie geringe Kontrast Effizienz und schnelle renale Ausscheidung. Makromolekulare und mehrwertige CAs kann eine gute Lösung für diese Probleme 4 sein. Da CA biodistribution wird vor allem durch ihre Größe bestimmt, hochmolekularen CAs Anzeige viel längere Retentionszeiten innerhalb von Geweben. Ebenso wichtig ist , die Multivalenz dieser Mittel führt zu einer erhöhten lokalen Konzentration des monomeren MR - Sonde (beispielsweise GdDOTA complex), im wesentlichen den erfassten MR - Signals und die Messqualität zu verbessern. Dendrimere sind unter den am meisten bevorzugten Gerüste für die Herstellung von mehrwertigen CAs für MRI 4,5. Diese hochverzweigten Makromoleküle mit definierter Größen sind anfällig für verschiedene Kopplungsreaktionen auf ihrer Oberfläche. In dieser Arbeit berichten wir über die Herstellung, Reinigung und Charakterisierung eines dendrimeren CA für die MRT, bestehend aus einer Generation 4 (G4) Poly (Amidoamin) (PAMAM) Dendrimer gekoppelt GdDOTA artigen Chelate (DCA). Wir beschreiben die Synthese des reaktiven DOTA-Derivat und dessen Kopplung an das PAMAM-Dendrimer. Folge der Komplexbildung mit Gd (III), die Standard-physikochemische Charakterisierung procedure von DCA durchgeführt wurde. Schließlich wurden MRI-Experimente ausgeführt, um die Fähigkeit von DCA zu erzeugen MR-Bilder mit einem stärkeren Kontrast als die von niedermolekularen CAs erhalten zu demonstrieren.

<table><tbody><tr><td>Cyclen</td><td>CheMatech</td><td>C002</td><td></td></tr><tr><td>&lt;em&gt;tert&lt;/em&gt;-Butyl bromoacetate&amp;nbsp;</td><td>Alfa Aesar</td><td>A14917</td><td></td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-Dimethylformamide</td><td>Fluka</td><td>40248</td><td></td></tr><tr><td>Potassium carbonate</td><td>Sigma-Aldrich</td><td>209619</td><td></td></tr><tr><td>4-(4-Nitrophenyl)butryic acid</td><td>Aldrich</td><td>335339</td><td></td></tr><tr><td>Thionyl chloride&amp;nbsp;</td><td>Acros Organics</td><td>382662500</td><td>Note: Corrosive substance; toxic if inhaled</td></tr><tr><td>Bromine</td><td>Acros Organics</td><td>402841000</td><td>Note: causes severe skin burns, fatal if inhaled&amp;nbsp;</td></tr><tr><td>Diethyl ether</td><td>any source</td><td></td><td></td></tr><tr><td>Sodium sulphate</td><td>Acros Organics</td><td>196640010</td><td></td></tr><tr><td>Chloroform&amp;nbsp;</td><td>VWR Chemicals</td><td>22711.29</td><td></td></tr><tr><td>&lt;em&gt;tert&lt;/em&gt;-Butyl 2,2,2-trichloroacetimidate</td><td>Aldrich</td><td>364789</td><td>Note: flammable substance; irritrant to skin and eyes</td></tr><tr><td>Boron trifluoride etherate</td><td>Acros Organics</td><td>174560250</td><td>48% BF&lt;sub&gt;3&lt;/sub&gt;. Note: Flammable substance; causes skin burns, fatal if inhaled</td></tr><tr><td>Sodium bicarbonate</td><td>Acros Organics</td><td>424270010</td><td></td></tr><tr><td>Ethyl-acetate</td><td>any source</td><td></td><td>For column chromatography</td></tr><tr><td>&lt;em&gt;n&lt;/em&gt;-Hexane</td><td>any source</td><td></td><td>For column chromatography</td></tr><tr><td>Bulb-to-bulb (Kugelrohr) distillation apparatus</td><td>B&amp;uuml;chi</td><td></td><td>Model type: Glass oven B-585</td></tr><tr><td>Silicagel</td><td>Carl Roth GmbH</td><td>P090.2</td><td></td></tr><tr><td>Methanol</td><td>any source</td><td></td><td>For column chromatography</td></tr><tr><td>Dichloromethane&amp;nbsp;</td><td>any source</td><td></td><td>For column chromatography</td></tr><tr><td>Ethanol</td><td>VWR Chemicals</td><td>20821.296</td><td></td></tr><tr><td>Ammonia</td><td>Acros Organics</td><td>428381000</td><td>7 N Solution in Methanol</td></tr><tr><td>Palladium</td><td>Aldrich</td><td>643181</td><td>15% wet</td></tr><tr><td>Hydrogenation apparatus PARR</td><td>PARR Instrument Company</td><td></td><td></td></tr><tr><td>Celite 503</td><td>Aldrich</td><td>22151</td><td></td></tr><tr><td>Sintered glass funnel</td><td>any source</td><td></td><td></td></tr><tr><td>Thiophosgen</td><td>Aldrich</td><td>115150</td><td>Note: irritrant to skin; toxic if inhaled</td></tr><tr><td>Triethylamine</td><td>Alfa Aesar</td><td>A12646</td><td></td></tr><tr><td>Dichloromethane&amp;nbsp;</td><td>Acros Organics</td><td>348460010</td><td>Extra dry&amp;nbsp;</td></tr><tr><td>Magnetic stirrer</td><td>any source</td><td></td><td></td></tr><tr><td>PAMAM G4 Dendrimer</td><td>Andrews ChemService</td><td>AuCS - 297</td><td>10% wt. solution in MeOH</td></tr><tr><td>Lipophylic Sephadex LH-20</td><td>Sigma</td><td>LH20100</td><td></td></tr><tr><td>Thin-layer chromatography plates</td><td>Merck Millipore</td><td>1.05554.0001</td><td></td></tr><tr><td>Formic acid</td><td>VWR Chemicals</td><td>20318.297</td><td></td></tr><tr><td>Lophylizer&amp;nbsp;</td><td>any source</td><td></td><td></td></tr><tr><td>Gadollinium(III) chloride hexahydrate</td><td>Aldrich</td><td>G7532</td><td></td></tr><tr><td>Sodium hydroxide</td><td>Acros Organics</td><td>134070010</td><td></td></tr><tr><td>pH meter</td><td>any source</td><td></td><td></td></tr><tr><td>Ethylenediaminetetraacetic acid disodium salt dihydrate</td><td>Aldrich</td><td>E5134</td><td></td></tr><tr><td>Mass spectrometer (ESI)</td><td>Agilent</td><td></td><td>Ion trap SL 1100&amp;nbsp;</td></tr><tr><td>Acetate buffer</td><td>any source</td><td></td><td>pH 5.8</td></tr><tr><td>Xylenol orange</td><td>Aldrich</td><td>52097</td><td>20 &amp;mu;M in acetate buffer</td></tr><tr><td>Hydrophylic Sephadex G-15</td><td>GE Healthcare</td><td>17-0020-01</td><td></td></tr><tr><td>Amicon Ultra-15 Centrifugal Filter Unit</td><td>Merck Millipore</td><td>UFC900324</td><td>Ultracel-3 membrane (MWCO 3000)</td></tr><tr><td>Centrifuge</td><td>any source</td><td></td><td></td></tr><tr><td>NMR spectrometer&amp;nbsp;</td><td>Bruker</td><td></td><td>Avance III 300 MHz</td></tr><tr><td>Topspin</td><td>Bruker</td><td></td><td>Version 2.1</td></tr><tr><td>Combustion analysis instrument</td><td>EuroVector SpA</td><td></td><td>EuroEA 3000 Elemental Analyser&amp;nbsp;</td></tr><tr><td>MALDI-ToF MS instrument</td><td>Applied Biosystems</td><td></td><td>Voyager-STR</td></tr><tr><td>Deuteriumoxid</td><td>Carl Roth GmbH</td><td>6672.3</td><td></td></tr><tr><td>&lt;em&gt;tert&lt;/em&gt;-Butyl alcohol</td><td>Carl Roth GmbH</td><td>AE16.1</td><td></td></tr><tr><td>Vortex mixer</td><td>any source</td><td></td><td></td></tr><tr><td>Norell NMR tubes</td><td>Deutero GmbH</td><td>507-HP-7</td><td></td></tr><tr><td>NMR coaxial tube</td><td>Deutero GmbH</td><td>coaxialb-5-7</td><td></td></tr><tr><td>DLS instrument</td><td>Malvern</td><td></td><td>Zetasizer Nano ZS</td></tr><tr><td>0.20 &amp;mu;m PTFE filter&amp;nbsp;</td><td>Carl Roth GmbH</td><td>KC94.1</td><td></td></tr><tr><td>HEPES</td><td>Fisher BioReagents</td><td>BP310</td><td></td></tr><tr><td>Plastic tube vials</td><td>any source</td><td></td><td></td></tr><tr><td>Dotarem</td><td>Guerbet</td><td></td><td>NDC 67684-2000-1</td></tr><tr><td>MRI scanner</td><td>Bruker</td><td></td><td>BioSpec 70/30 USR magnet (7 T). Note: potential hazards related to high magnetic fields</td></tr><tr><td>RF coil</td><td>Bruker</td><td></td><td>Dual frequency volume coil (RF RES 300 1H/19F 075/040 LIN/LIN TR)</td></tr><tr><td>Paravision (software)</td><td>Bruker</td><td></td><td>Version 5.1</td></tr></tbody></table>

preparation and in vitro characterization of dendrimer-based contrast agents for magnetic resonance imaging

Paramagnetische Komplexe von Gadolinium (III) mit acyclischen oder makrocyclischen Chelate sind die am häufigsten verwendeten Kontrastmittel (CAs) für die Magnetresonanztomographie (MRI). Ihr Zweck ist es, die Relaxationsrate von Wasserprotonen in Gewebe zu verbessern, wodurch die MR Bildkontrast und die Spezifität der MRI-Messungen. Strom klinisch zugelassenen Kontrastmittel sind niedermolekulare Moleküle, die vom Körper rasch gelöscht werden. Die Verwendung von Dendrimere als Träger von paramagnetischem Chelatoren kann eine wichtige Rolle bei der zukünftigen Entwicklung von effizienteren MRI-Kontrastmittel spielen. Insbesondere die Erhöhung der lokalen Konzentration der paramagnetischen Spezies führt zu einem höheren Signalkontrast. Darüber hinaus liefert diese CA eine längere Geweberetentionszeit aufgrund seines hohen Molekulargewicht und -größe. Hier zeigen wir, ein praktikables Verfahren zur Herstellung von hochmolekularen MRI-Kontrastmittel auf Basis von Poly (amidoamin) (PAMAM) Dendrimere mit monomacrozyklischen DOTA-Typ Chelatoren (DOTA - 1,4,7,10-Tetraazacyclododecan-1,4,7,10-tetraacetate). Die chelatbildende Einheit wurde durch Ausnutzen der Reaktivität des Isothiocyanat (NCS) Gruppe in Richtung der Aminoberflächengruppen des PAMAM Dendrimer beigefügten Thioharnstoff Brücken zu bilden. Dendrimeren Produkte wurden mittels Kernresonanzspektroskopie, Massenspektrometrie gereinigt und analysiert, und die Elementaranalyse. Schließlich wurden hochaufgelöste MR-Bilder aufgenommen und die Signal Kontraste aus dem vorbereiteten dendrimeren und den im Handel erhältlichen monomeren Mittel verglichen wurden erhalten.

Die Herstellung von DCA bestand aus zwei Stufen: 1) Synthese des monomeren DOTA-Typ - Chelator (Abbildung 1) und 2) Kopplung des Chelators mit dem G4 PAMAM Dendrimer und anschließende Herstellung der dendrimeren Gd (III) -Komplex (Figur 2) . In der ersten Stufe wird ein cyclen Basis DOTA-Typ Chelator vier Carbonsäuren und eine orthogonale Gruppe geeignet für die weitere synthetische Modifikationen enthielt, wurde hergestellt. Die Hers...

Watch this Scientific Journal Video about Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging at JoVE.com

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Dieses Protokoll beschreibt die Herstellung und Charakterisierung eines dendrimeren Magnetresonanztomographie (MRI), die Kontrastmittel trägt cyclen basierenden makrocyclischen Chelate paramagnetischen Ionen Gadolinium- koordinieren. In einer Reihe von MRI - Experimente in vitro produzierte dieses Mittel ein verstärktes MRI - Signal , wenn an dem handelsüblichen monomeren Analogon verglichen.

Vorbereitung und<em&gt; In Vitro</em&gt; Charakterisierung der für Magnetresonanz-Kontrastmittel Dendrimer-basierten

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

preparation-vitro-characterization-dendrimer-based-contrast-agents

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

9.8K Aufrufe.  Max Planck Institute for Biological Cybernetics.  Dieses Protokoll beschreibt die Herstellung und Charakterisierung eines dendrimeren Magnetresonanztomographie (MRI), die Kontrastmittel trägt cyclen basierenden makrocyclischen Chelate paramagnetischen Ionen Gadolinium- koordinieren. In einer Reihe von MRI - Experimente in vitro produzierte dieses Mittel ein verstärktes MRI - Signal , wenn an dem handelsüblichen monomeren Analogon verglichen. 

Serie: Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end organs. The latter include the lung, RES, and brain and are operative during human immunodeficiency virus type one (HIV-1) infection. Macrophage entry into tissues is notable in areas of active HIV-1 replication and sites of inflammation. In order to assess the potential of macrophages as nanocarriers, superparamagnetic iron-oxide and/or drug laden particles coated with surfactants were parenterally injected into HIV-1 encephalitic mice. This was done to quantitatively assess particle and drug biodistribution. Magnetic resonance imaging (MRI) test results were validated by histological coregistration and enhanced image processing. End organ disease as typified by altered brain histology were assessed by MRI. The demonstration of robust migration of nanoformulations into areas of focal encephalitis provides '"proof of concept" for the use of advanced bioimaging techniques to monitor macrophage migration. Importantly, histopathological aberrations in brain correlate with bioimaging parameters making the general utility of MRI in studies of cell distribution in disease feasible. We posit that using such methods can provide a real time index of disease burden and therapeutic efficacy with translational potential to humans.

Bioimaging methods used to assess cell biodistribution of nanoparticles are applicable for therapeutic and diagnostic monitoring of nanoformulated compounds. The methods described herein are sensitive and specific when assessed by histological coregistration. The methodologies provide a translational pathway from rodent to human applications.

Registrierte Bioimaging von Nanomaterialien für Diagnostische und Therapeutische Überwachung

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end ...

Forschung

Biotechnik

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

The development of fluorescent indicators represented a revolution for life sciences. Genetically encoded and synthetic fluorophores with sensing abilities allowed the visualization of biologically relevant species with high spatial and temporal resolution. Synthetic dyes are of particular interest thanks to their high tunability and the wide range of measureable analytes. However, these molecules suffer several limitations related to small molecule behavior (poor solubility, difficulties in targeting, often no ratiometric imaging allowed). In this work we introduce the development of dendrimer-based sensors and present a procedure for pH measurement in vitro, in living cells and in vivo. We choose dendrimers as ideal platform for our sensors for their many desirable properties (monodispersity, tunable properties, multivalency) that made them a widely used scaffold for several biomedical devices. The conjugation of fluorescent pH indicators to the dendrimer scaffold led to an enhancement of their sensing performances. In particular dendrimers exhibit reduced cell leakage, improved intracellular targeting and allow ratiometric measurements. These novel sensors were successfully employed to measure pH in living HeLa cells and in vivo in mouse brain.

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

Fluorescence sensors are powerful tools in life science. Here we describe a methodology to synthesize and use dendrimer-based fluorescent sensors to measure pH in living cells and in vivo. The dendritic scaffold enhances the properties of conjugated fluorescent dyes leading to improved sensing properties.

Synthesis, Cellular Lieferung und<em&gt; In-vivo-</em&gt; Anwendung der Dendrimer-basierten pH-Sensoren

The development of  fluorescent indicators represented a revolution for life sciences. Genetically  encoded and synthetic fluorophores with sensing ...

Chemie

In vitro Labeling of Human Embryonic Stem Cells for Magnetic Resonance Imaging

Human embryonic stem cells (hESC) have demonstrated the ability to restore the injured myocardium. Magnetic resonance imaging (MRI) has emerged as one of the predominant imaging modalities to assess the restoration of the injured myocardium. Furthermore, ex-vivo labeling agents, such as iron-oxide nanoparticles, have been employed to track and localize the transplanted stem cells. However, this method does not monitor a fundamental cellular biology property regarding the viability of transplanted cells. It has been known that manganese chloride (MnCl2) enters the cells via voltage-gated calcium (Ca2+) channels when the cells are biologically active, and accumulates intracellularly to generate T1 shortening effect. Therefore, we suggest that manganese-guided MRI can be useful to monitor cell viability after the transplantation of hESC into the myocardium.
In this video, we will show how to label hESC with MnCl2 and how those cells can be clearly seen by using MRI in vitro. At the same time, biological activity of Ca2+-channels will be modulated utilizing both Ca2+-channel agonist and antagonist to evaluate concomitant signal changes.

In this video, we are showing how to label human embryonic stem cells (hESC) with manganese chloride (MnCl2) which can enter cells via voltage-gated calcium channels when the cells are biologically active. Additionally, we show the use of MnCl2 as cellular MRI contrast agent to determine the in vitro viability of hESC.

In-vitro-Markierung von humanen embryonalen Stammzellen für Magnetic Resonance Imaging

Human embryonic stem cells (hESC) have demonstrated the ability to restore the injured myocardium. Magnetic resonance imaging (MRI) has emerged as one of ...

Biologie

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Continuous advancements in noninvasive imaging modalities such as magnetic resonance imaging (MRI) have greatly improved our ability to study physiological or pathological processes in living organisms. MRI is also proving to be a valuable tool for capturing transplanted cells in vivo. Initial cell labeling strategies for MRI made use of contrast agents that influence the MR relaxation times (T1, T2, T2*) and lead to an enhancement (T1) or depletion (T2*) of signal where labeled cells are present. T2* enhancement agents such as ultrasmall iron oxide agents (USPIO) have been employed to study cell migration and some have also been approved by the FDA for clinical application. A drawback of T2* agents is the difficulty to distinguish the signal extinction created by the labeled cells from other artifacts such as blood clots, micro bleeds or air bubbles. In this article, we describe an emerging technique for tracking cells in vivo that is based on labeling the cells with fluorine (19F)-rich particles. These particles are prepared by emulsifying perfluorocarbon (PFC) compounds and then used to label cells, which subsequently can be imaged by 19F MRI. Important advantages of PFCs for cell tracking in vivo include (i) the absence of carbon-bound 19F in vivo, which then yields background-free images and complete cell selectivityand(ii) the possibility to quantify the cell signal by 19F MR spectroscopy.

Monitoring Dendritic Cell Migration using 19F / 1H Magnetic Resonance Imaging

Tracking of cells using MRI has gained remarkable attention in the past years. This protocol describes the labeling of dendritic cells with fluorine (19F)-rich particles, the in vivo application of these cells, and monitoring the extent of their migration to the draining lymph node with 19F/1H MRI and 19F MRS.

Überwachung dendritische Zellen mit Migration<sup&gt; 19</sup&gt; F /<sup&gt; 1</sup&gt; H Magnetic Resonance Imaging

Continuous  advancements in noninvasive imaging modalities such as magnetic resonance  imaging (MRI) have greatly improved our ability to study ...

Immunologie und Infektion

MR Molecular Imaging of Prostate Cancer with a Small Molecular CLT1 Peptide Targeted Contrast Agent

Tumor extracellular matrix has abundance of cancer related proteins that can be used as biomarkers for cancer molecular imaging. In this work, we demonstrated effective MR cancer molecular imaging with a small molecular peptide targeted Gd-DOTA monoamide complex as a targeted MRI contrast agent specific to clotted plasma proteins in tumor stroma. We performed the experiment of evaluating the effectiveness of the agent for non-invasive detection of prostate tumor with MRI in a mouse orthotopic PC-3 prostate cancer model. The targeted contrast agent was effective to produce significant tumor contrast enhancement at a low dose of 0.03 mmol Gd/kg. The peptide targeted MRI contrast agent is promising for MR molecular imaging of prostate tumor.

To demonstrate MR cancer molecular imaging with a small peptide targeted MRI contrast agent specific to clotted plasma proteins in tumor stroma in a mouse prostate cancer model.

MR Molekulare Bildgebung von Prostatakrebs mit einem kleinen Molecular Targeted CLT1 Peptid-Kontrastmittel

Tumor extracellular  matrix has abundance of cancer related proteins that can be used as biomarkers  for cancer molecular imaging. In this work,  we ...

Medizin

Biofunctionalized Prussian Blue Nanoparticles for Multimodal Molecular Imaging Applications

Multimodal, molecular imaging allows the visualization of biological processes at cellular, subcellular, and molecular-level resolutions using multiple, complementary imaging techniques. These imaging agents facilitate the real-time assessment of pathways and mechanisms in vivo, which enhance both diagnostic and therapeutic efficacy. This article presents the protocol for the synthesis of biofunctionalized Prussian blue nanoparticles (PB NPs) - a novel class of agents for use in multimodal, molecular imaging applications. The imaging modalities incorporated in the nanoparticles, fluorescence imaging and magnetic resonance imaging (MRI), have complementary features. The PB NPs possess a core-shell design where gadolinium and manganese ions incorporated within the interstitial spaces of the PB lattice generate MRI contrast, both in T1 and T2-weighted sequences. The PB NPs are coated with fluorescent avidin using electrostatic self-assembly, which enables fluorescence imaging. The avidin-coated nanoparticles are modified with biotinylated ligands that confer molecular targeting capabilities to the nanoparticles. The stability and toxicity of the nanoparticles are measured, as well as their MRI relaxivities. The multimodal, molecular imaging capabilities of these biofunctionalized PB NPs are then demonstrated by using them for fluorescence imaging and molecular MRI in vitro.

This protocol describes the synthesis of biofunctionalized Prussian blue nanoparticles and their use as multimodal, molecular imaging agents. The nanoparticles have a core-shell design where gadolinium or manganese ions within the nanoparticle core generate MRI contrast. The biofunctional shell contains fluorophores for fluorescence imaging and targeting ligands for molecular targeting.

Biofunktionalisierten Prussian Blue Nanopartikel für Molekulare Bildgebung Multimodale Anwendungen

Multimodal, molecular imaging allows the visualization of biological processes at cellular, subcellular, and molecular-level resolutions using multiple, ...

In vivo 19F MRI for Cell Tracking

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. Here, we describe a general protocol for cell labeling, imaging, and image processing. The technique is applicable to various cell types and animal models, although here we focus on a typical mouse model for tracking murine immune cells. The most important issues for cell labeling are described, as these are relevant to all models. Similarly, key imaging parameters are listed, although the details will vary depending on the MRI system and the individual setup. Finally, we include an image processing protocol for quantification. Variations for this, and other parts of the protocol, are assessed in the Discussion section. Based on the detailed procedure described here, the user will need to adapt the protocol for each specific cell type, cell label, animal model, and imaging setup. Note that the protocol can also be adapted for human use, as long as clinical restrictions are met.

In vivo 19F MRI for Cell Tracking

We describe a general protocol for in vivo cell tracking using MRI in a mouse model with ex vivo labeled cells. A typical protocol for cell labeling, image acquisition processing and quantification is included.

In-vivo-19 F-MRT für die Zellverfolgung

In vivo 19F MRI allows quantitative cell tracking without the use of ionizing radiation. It is a noninvasive technique that can be applied to humans. ...

<meta charset="utf8"></head><body>Eisenoxid-Nanopartikel für die bildgestützte Therapieverabreichung beim murinen Glioblastom

Nanoparticle Delivery of an Oligonucleotide Payload in a Glioblastoma Multiforme Animal Model

Glioblastoma multiforme (GBM) is the most common and aggressive form of primary brain malignancy for which there is no cure. The blood-brain barrier is a significant hurdle in the delivery of therapies to GBM. Reported here is an image-guided, iron oxide-based therapeutic delivery nano platform capable of bypassing this physiological barrier by virtue of size and accumulating in the tumor region, delivering its payload. This 25 nm nano platform consists of crosslinked dextran-coated iron oxide nanoparticles labeled with Cy5.5 fluorescent dye and containing antisense oligonucleotide as a payload. The magnetic iron oxide core enables tracking of the nanoparticles through in vivo magnetic resonance imaging, while Cy5.5 dye allows tracking by optical imaging. This report details the monitoring of the accumulation of this nanoparticle platform (termed MN-anti-miR10b) in orthotopically implanted glioblastoma tumors following intravenous injection. In addition, it provides insight into the in vivo delivery of RNA oligonucleotides, a problem that has hampered the translation of RNA therapeutics into the clinic.

<meta charset="utf8"></head><body>Autor im Rampenlicht: Innovative Krebstherapien mit Eisenoxid-Nanopartikeln zur Behandlung von Glioblastomen

The blood-brain barrier is a significant hurdle in the delivery of therapies for glioblastoma, a disease for which there is no cure. Here, we report an in vivo image-guided iron oxide therapeutic nano platform that can bypass this physiological barrier by virtue of size and accumulate in the tumor.

Nanopartikel-Verabreichung einer Oligonukleotid-Nutzlast in einem Glioblastom-Multiforme-Tiermodell

Glioblastoma multiforme (GBM) is the most common and aggressive form of primary brain malignancy for which there is no cure. The blood-brain barrier is a ...

Vorbereitung und

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In-vitro-Markierung von humanen embryonalen Stammzellen für Magnetic Resonance Imaging

Überwachung dendritische Zellen mit Migration

MR Molekulare Bildgebung von Prostatakrebs mit einem kleinen Molecular Targeted CLT1 Peptid-Kontrastmittel

Biofunktionalisierten Prussian Blue Nanopartikel für Molekulare Bildgebung Multimodale Anwendungen

^In-vivo-19 F-MRT für die Zellverfolgung

Nanopartikel-Verabreichung einer Oligonukleotid-Nutzlast in einem Glioblastom-Multiforme-Tiermodell

Nanopartikel-Verabreichung einer Oligonukleotid-Nutzlast in einem Glioblastom-Multiforme-Tiermodell

Nanopartikel-Verabreichung einer Oligonukleotid-Nutzlast in einem Glioblastom-Multiforme-Tiermodell