Polyurethane based organic macromolecular contrast agents (PU-ORCAs) for magnetic resonance imaging

Garmendia, Sofiem; Mantione, Daniele; Castro, Silvia Alonso‐de; Jehanno, Coralie; Lezama, Luis; Hedrick, James L.; Mecerreyes, David; Salassa, Luca; Sardón, Haritz

doi:10.1039/c7py00166e

Cited by 28 publications

(35 citation statements)

References 35 publications

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“…Compared to the common model nitroxide 3-carbamoyl-PROXYL (3-CP), the r 2 values obtained from the PEtOx-based BASPs are 11–13.5 larger 47 and are up to 7.5-fold larger than a recently reported polyurethane-based ORCA. 60 Nevertheless, these values are still below those of analogous PEG-based BASP-ORCAs (4.67 mM −1 s −1 ). 47 Apart from the absolute relaxivity, the r 2 / r 1 ratio is also crucial for achieving optimal T 2 -weighted MRI contrast.…”

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confidence: 87%

Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents

et al. 2019

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The synthesis of functional poly(2-alkyl-2-oxazoline) (PAOx) copolymers with complex nanoarchitectures using a graft-through ring-opening metathesis polymerization (ROMP) approach is described. First, well-defined norbornene-terminated poly(2-ethyl-2-oxazoline) (PEtOx) macromonomers (MM) were prepared by cationic ringopening polymerization. ROMP of these MMs produced bottlebrush copolymers with PEtOx side chains. In addition, PEtOx-based branched MMs bearing a terminal alkyne group were prepared and conjugated to an azidecontaining bis-spirocyclohexyl nitroxide via Cu-catalyzed azide-alkyne cycloaddition (CuAAC). ROMP of this branched MM, followed by in situ cross-linking, provided PEtOx-based brush-arm star polymers (BASPs) with nitroxide radicals localized at the core-shell interface. These PEtOx-*

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confidence: 87%

Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents

et al. 2019

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“…The largest drawback of using nitroxides as contrast agents is the fact that these organic radicals often possess only one unpaired electron in contrast to metals, which have seven (Gd), five (Mg), or four (Fe). Therefore, the research has lately focused on macromolecular nitroxide contrast agents [ 12 , 13 , 14 , 15 , 16 ]. This allows inserting several radical units to the contrast agent structure.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Stability and Relaxivity of TEEPO-Met: An Organic Radical as a Potential Tumour Targeting Contrast Agent for Magnetic Resonance Imaging

et al. 2018

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Cancer is a widespread and life-threatening disease and its early-stage diagnosis is vital. One of the most effective, non-invasive tools in medical diagnostics is magnetic resonance imaging (MRI) with the aid of contrast agents. Contrast agents that are currently in clinical use contain metals, causing some restrictions in their use. Also, these contrast agents are mainly non-specific without any tissue targeting capabilities. Subsequently, the interest has notably increased in the research of organic, metal-free contrast agents. This study presents a new, stable organic radical, TEEPO-Met, where a radical moiety 2,2,6,6-tetraethylpiperidinoxide (TEEPO) is attached to an amino acid, methionine (Met), as a potentially tumour-targeting moiety. We describe the synthesis, stability assessment with electron paramagnetic resonance (EPR) spectroscopy and relaxation enhancement abilities by an in vitro nuclear magnetic resonance (NMR) and phantom MRI studies of TEEPO-Met. The new compound proved to be stable notably longer than the average imaging time in conditions mimicking a biological matrix. Also, it significantly reduced the relaxation times of water, making it a promising candidate as a novel tumour targeting contrast agent for MRI.

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“…42–44 In addition, progress toward the development of significantly more stable “reduction resistant” ORCAs has been made. 45–48 Moreover, several groups have developed nitroxide-based MRI CAs 49 where nitroxides are incorporated into a multitude of scaffolds ranging from cyclodextrin 50 and lipids 51 to polymeric systems, 52–54 including polyurethane 55 or polyacetylene. 56 Despite such advances, these systems generally suffer from low water solubility, poor nitroxide reduction resistance, insuﬃcient relaxivity, and/or a lack of in vivo optimization that precludes further development.…”

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confidence: 99%

Triply Loaded Nitroxide Brush-Arm Star Polymers Enable Metal-Free Millimetric Tumor Detection by Magnetic Resonance Imaging

et al. 2018

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Nitroxides occupy a privileged position among plausible metal-free magnetic resonance imaging (MRI) contrast agents (CAs) due to their inherently low-toxicity profiles; nevertheless, their translational development has been hindered by a lack of appropriate contrast sensitivity. Nanostructured materials with high nitroxide densities, where each individual nitroxide within a macromolecular construct contributes to the image contrast, could address this limitation, but the synthesis of such materials remains challenging. Here, we report a modular and scalable synthetic

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Polyurethane based organic macromolecular contrast agents (PU-ORCAs) for magnetic resonance imaging

Abstract: Combination of its convenience for non-invasive application and high spatial resolution make Magnetic Resonance Imaging (MRI) one of the leading imaging modalities.

Cited by 28 publications

References 35 publications

Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents

Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents

Synthesis, Stability and Relaxivity of TEEPO-Met: An Organic Radical as a Potential Tumour Targeting Contrast Agent for Magnetic Resonance Imaging

Triply Loaded Nitroxide Brush-Arm Star Polymers Enable Metal-Free Millimetric Tumor Detection by Magnetic Resonance Imaging

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