Gadolinium-coordinated elastic nanogels for in vivo tumor targeting and imaging

Facile synthesis of gadolinium (III) chelates functionalized carbon quantum dots for fluorescence and magnetic resonance dual-modal bioimaging

“…signaling in cells [42][43][44]. It has been reported previously that IC 50 and LD 50 for free Gd 3+ is ~0.2 mM and 0.4 mmol kg -1 , respectively [43][44][45][46]. The cytotoxicity of CQD-DTPA-Gd was evaluated using an MTT assay with 5.0 µM cisplatin as positive control.…”

Nanogels: An overview of properties, biomedical applications and obstacles to clinical translation

“…Alternatively to post polymerization functionalization of nanogel with contrast agents, Gd-chelates can be incorporated into nanogels within the crosslinking moieties or Gd 3+ ions can be used as metal crosslinkers themselves. The later strategy was utilized by Kim and coworkers to prepare Gd-coordinated nanogels by crosslinking of branched PEI with Gd 3+ ions in inverse microemulsion followed by surface functionalization with PEG chains in order to increase the blood circulation time [175]. It was shown that polydentate chelation by PEI is robust enough to minimize the liberation of toxic Gd 3+ ions under the physiological conditions.…”

“…Another multi-imaging study using nanogel-based dual MRI and optical imaging probe was reported by Lim et al Core-shell nanogels containing Gd +3 -coordinated PEI core and PEG shell were functionalized with a NIR dye, Cy5.5 and evaluated in SCC7 tumor-bearing mice [175]. Although no targeting group was attached to the nanogels, tumors displayed strong NIR fluorescence signals up to 1 day post injection.…”

“…Notably, the amount of injected nanogels corresponded to a much lower dose of contrast agent (38 μmol Gd/kg) than the standard dose of Gd-DTPA (100 μmol Gd/kg) and no notable contrast enhancement was observed in T 1 -weighted images. However, a significant signal darkening was seen in certain regions of the tumor at 2 h post-injection, visualizing the intratumor structure at high spatial resolution, indicating that these nanogels could act as negative contrast enhancers (see section 4.1) for tumor imaging with the added advantage of fluorescence imaging [175]. …”

Long-Lasting and Efficient Tumor Imaging Using a High Relaxivity Polysaccharide Nanogel Magnetic Resonance Imaging Contrast Agent

“…25−28 Despite the advantages of nanogels, only a few nanogel MRI contrast agents have been developed recently 29,30 including one developed previously by the Almutairi group. 23 Our system was composed of polyacrylamide nanogels with metal chelating cross-linkers making it a versatile system for both positron emission tomography (PET) and MRI.…”