PEGylated amphiphilic polymeric manganese( ii ) complexes as magnetic resonance angiographic agents

ACS Appl. Mater. Interfaces

Liu

et al. 2023

Self Cite

Compared to traditional branched polymers with Gd(III) chelates conjugated on their surface, branched polymers with Gd(III) chelates as the internal skeleton are considered to be a reasonable strategy for preparing efficient magnetic resonance imaging contrast agents. Herein, the Gd(III) ligand DOTA was chosen as the internal skeleton; four different molecular weights (3.5, 5.3, 8.6, and 13.1 kDa) and degrees of branching poly-DOTA branched polymers (P1, P2, P3, and P4) were synthesized by a simple “A2 + B4”-type one-pot polymerization. The Gd(III) chelates of these poly-DOTA branched polymers (P1-Gd, P2-Gd, P3-Gd, and P4-Gd) display excellent kinetic stability, which is significantly higher than those of linear Gd-DTPA and cyclic Gd-DOTA-butrol and slightly lower than that of cyclic Gd-DOTA. The T 1 relaxivities of P1-Gd, P2-Gd, P3-Gd, and P4-Gd are 29.4, 38.7, 44.0, and 47.9 Gd mM–1 s–1, respectively, at 0.5 T, which are about 6–11 times higher than that of Gd-DOTA (4.4 Gd mM–1 s–1). P4-Gd was selected for in vivo magnetic resonance angiography (MRA) because of its high kinetic stability, T 1 relaxivity, and good biosafety. The results showed excellent MRA effect, sensitive detection of vascular stenosis, and prolonged observation window as compared to Gd-DOTA. Overall, Gd(III) chelates of poly-DOTA branched polymers are good candidates of MRI probes, providing a unique design strategy in which Gd chelation can occur at both the interior and surface of the poly-DOTA branched polymers, resulting in excellent relaxivity enhancement. In vivo animal MRA studies of the probe provide possibilities in discovering small vascular pathologies.

Section: Methodsmentioning

confidence: 99%

Gadolinium(III) Complex-Backboned Branched Polymers as Imaging Probes for Contrast-Enhanced Magnetic Resonance Angiography

ACS Appl. Mater. Interfaces

Liu

et al. 2023

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“…The longitudinal relaxivity ( r 1 ) and the ratio of transverse relaxivity ( r 2 ) to longitudinal relaxivity ( r 2 / r 1 ) have been considered as golden standards to assess the contrast efficiency of T 1 CAs. 39,40 An ideal T 1 CA should possess both a high r 1 value and a low r 2 / r 1 ratio. In this work, the relaxivities of these MnO 2 /PAA NPs were tested on MRI scanners at 0.5 T, 1.5 T and 3.0 T magnetic fields, respectively.…”

Section: Resultsmentioning

confidence: 99%

Ultra-small manganese dioxide nanoparticles with high T₁ relaxivity for magnetic resonance angiography

Jiang

et al. 2023

Biomater. Sci.

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“…Compared with water-soluble polymer contrast agents, the stable amphiphilic nanoparticle structure supplies a more rigid platform which can effectively increase stability of chelation [ 22 , 24 , 29 ]. Herein, PU(L-R-PEG) was self-assembled into nanoparticles in water.…”

Section: Resultsmentioning

confidence: 99%

68Ga-labeled amphiphilic polymer nanoparticles for PET imaging of sentinel lymph node metastasis

Chen

Regenerative Biomaterials

et al. 2023

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Precise diagnosis of lymph node metastasis is important for therapeutic regimen planning, prognosis analysis and probably better outcomes for cancer patients. In this work, 68Ga-labeled amphiphilic alternating copolymers nanoparticles with different rigid ligands were synthesized as positron emission tomography (PET) probes for lymph node metastasis imaging. The labeling efficiency and stability of nanoparticles was improved with increased rigidity of coordination unit. PU(68Ga-L-MDI-PEG) nanoparticles (PU(68Ga-L-MDI-PEG) NPs) with the strongest rigidity of coordination unit exhibit the lowest critical micelle concentration, the best 68Ga labeling efficiency and stability. During in vivo lymph node metastasis imaging, PU(68Ga-L-MDI-PEG) NPs led to different accumulations in normal lymph nodes (N-LN) and tumor metastasized sentinel lymph nodes (T-SLN), which resulted in different PET signal presentation, making it feasible to differentiate N-LN from T-SLN. In comparison, small molecule probe 68GaL had poor lymph node accumulation, not only making it difficult to find lymph nodes on PET/CT scan, but also tough to distinguish normal lymph nodes from metastatic ones. Overall, this work provides a reference for design of 68Ga labeled polymeric nanoparticles with high chelation efficiency and stability, as sensitive PET probes for lymph node imaging.