Engineered Iron-Oxide-Based Nanoparticles as Enhanced T₁ Contrast Agents for Efficient Tumor Imaging

Abstract

We report the design and synthesis of small-sized zwitterion-coated gadolinium-embedded iron oxide (GdIO) nanoparticles, which exhibit a strong T1 contrast effect for tumor imaging through enhanced permeation and retention effect and the ability to clear out of the body in living subjects. The combination of spin-canting effects and the collection of gadolinium species within small-sized GdIO nanoparticles led to a significantly enhanced T1 contrast effect. For example, GdIO nanoparticles with a diameter of ~4.8 nm exhibited a high r1 relaxivity of 7.85 mM−1 · S−1 and a low r2/r1 ratio of 5.24. After being coated with zwitterionic dopamine sulfonate molecules, the 4.8 nm GdIO nanoparticles showed a steady hydrodynamic diameter (~5.2 nm) in both PBS buffer and fetal bovine serum solution, indicating a low nonspecific protein absorption. This study provides a valuable strategy for the design of highly sensitive iron-oxide-based T1 contrast agents with relatively long circulation half-lives (~50 min), efficient tumor passive targeting (SKOV3, human ovarian cancer xenograft tumor as a model), and the possibility of rapid renal clearance after tumor imaging.

Zwitterionic ceramics for biomedical applications

“…This has been exploited to develop 10 nm-sized zwitterionic SPIONPs sing a compact DOPA sulfonate ligand (structure 3, Figure 2) [28][29][30].…”

Engineering iodine-doped carbon dots as dual-modal probes for fluorescence and X-ray CT imaging

“…Importantly, ultrasmall size nanoparticles circulating in the blood might also increase the possibility of passive targeting in tumors by enhancing permeation and retention effect. 32,33 Based on these results, we proposed that the I-doped CDs as ideal CT contrast agents had the potential to efficiently target the region of interest (eg, diseased area or tumor), after systemic administration, with unbound rapidly renal clearance from the host. …”

Solubility limit, magnetic interaction and conduction mechanism in rare earth doped spinel ferrite

“…These ferrites exhibit enhanced magneto optical kerr (MOKE) effect [20] and excellent microwave absorption properties [21,22]. Thus, these ferrites cover a wide range of applications chiefly based on their magnetic characteristics [17][18][19][20][21][22][23][24][25]. However, there is lack of understanding of magnetic interaction, conduction mechanism inside these ferrites [15,16].…”

“…In recent years, rare earth (RE) doped ferrites become interesting due to their superiority for various applications over other doped ferrite systems [17][18][19][20][21][22]. These systems become radioactive and exhibit potentential for biomedical applications [19] along-with efficient tumor passive targeting [23]. Improved capability of dye removal [24], waste water treatment [25], degradation of organic pollutants through photocatalytic activity [26] are other important fields of utilization of these ferrites.…”