Tunable T₁ and T₂ contrast abilities of manganese-engineered iron oxide nanoparticles through size control

Abstract

In this paper, we demonstrate the tunable T1 and T2 contrast abilities of engineered iron oxide nanoparticles with high performance for liver contrast-enhanced magnetic resonance imaging (MRI) in mice. To enhance the diagnostic accuracy of MRI, large numbers of contrast agents with T1 or T2 contrast ability have been widely explored. The comprehensive investigation of high-performance MRI contrast agents with controllable T1 and T2 contrast abilities is of high importance in the field of molecular imaging. In this study, we synthesized uniform manganese-doped iron oxide (MnIO) nanoparticles with controllable size from 5 to 12 nm and comprehensively investigated their MRI contrast abilities. We revealed that the MRI contrast effects of MnIO nanoparticles are highly size-dependent. By controlling the size of MnIO nanoparticles, we can achieve T1-dominated, T2-dominated, and T1-T2 dual-mode MRI contrast agents with much higher contrast enhancement than the corresponding conventional iron oxide nanoparticles.

Microwave-assisted green synthesis of superparamagnetic nanoparticles using fruit peel extracts: surface engineering, <em>T</em>₂ relaxometry, and photodynamic treatment potential

“…[8][9][10] Moreover, these processes mostly end up with hydrophobic nanoparticles (NPs), which are often subjected to surface engineering, making them water dispersible. [11][12][13] The absorption of NPs produced by hydrophobic polymers is greater than that of NPs produced by hydrophilic polymers. 14,15 However, hydrophobic NPs may induce genotoxicity, carcinogenicity, and teratogenicity; therefore, a hydrophilic surface is preferred over the hydrophobic surface for biomedical applications.…”

Enhanced magnetic resonance imaging and staining of cancer cells using ferrimagnetic H-ferritin nanoparticles with increasing core size

“…The increasing nanoparticle size may enhance the water protons chemically exchanging with surface paramagnetic centers of particles; consequently, T 1 relaxation enhanced. 31 The values of r 1 and ratio of r 2 /r 1 are important parameters for evaluating magnetic nanoparticles as MR-positive contrast agents. In general, T 1 agents have r 2 /r 1 ratios of 1-2.…”

Active-target T1-weighted MR Imaging of Tiny Hepatic Tumor via RGD Modified Ultra-small Fe3O4 Nanoprobes

“…It is noteworthy that T 1 -Fe 3 O 4 commonly possess ultra-small particle size, which not only provides optimal bright T 1 contrast effect, but also ensures that T 1 -Fe 3 O 4 preferentially accumulate in tumors with little liver uptake 9, 11-13. As a result, it could produce positive T 1 -weighted MRI contrast enhancement in hepatic tumor sites rather than the normal liver tissue as reported before,9, 14, 15 which could offer more accurate and sensitive diagnostic information during the early-stage detection of liver cancer. Unfortunately, there are many strict requirements in the process of constructing T 1 -Fe 3 O 4 based active-target probes.…”

“…Unfortunately, there are many strict requirements in the process of constructing T 1 -Fe 3 O 4 based active-target probes. Synthesis of Fe 3 O 4 NPs around core size of 5 nm (generally with hydrodynamic size of 10~20 nm), which has been proved to own reasonable renal excretion rate and favorable longitudinal relaxivity (r 1 ) is the primary request 4, 15, 16. Secondly, for active-target T 1 imaging of tumors, the bioconjugation reaction between specific ligands and T 1 -Fe 3 O 4 must be carried out in a well-controlled manner to prevent the formation of NPs aggregates as far as possible because the aggregates usually have large magnetic moment, strong T 2 effect and could be easily recognized by macrophages and accumulated in liver parenchyma 8, 17-19.…”