In vivo biodistribution of iron oxide nanoparticles: an overview

Abstract

Iron oxide nanoparticles present a promising alternative to conventional energy deposition-based tissue therapies. The success of such nanoparticles as a therapeutic for diseases like cancer, however, depends heavily on the particles’ ability to localize to tumor tissue as well as provide minimal toxicity to surrounding tissues and key organs such as those involved in the reticuloendothelial system (RES). We present here the results of a long term clearance study where mice injected intravenously with 2 mg Fe of 100 nm dextran-coated iron oxide nanoparticles were sacrificed at 14 and 580 days post injection. Histological analysis showed accumulation of the nanoparticles in some RES organs by the 14 day time point and clearance of the nanoparticles by the 580 day time point with no obvious toxicity to organs. An additional study reported herein employs 20 nm and 110 nm starch-coated iron oxide nanoparticles at 80 mg Fe/kg mouse in a size/biodistribution study with endpoints at 4, 24 and 72 hours. Preliminary results show nanoparticle accumulation in the liver and spleen with some elevated iron accumulation in tumoral tissues with differences between the 20 nm and the 110 nm nanoparticle depositions.

In vivo delivery, pharmacokinetics, biodistribution and toxicity of iron oxide nanoparticles

“…124 However, it is important to test the co-localization of the iron and fluorescent signals to make sure that the fluorescent signal is not just from the detached coating or fluorescent molecules due to their faster degradation and clearance rates. In a separate study, Tate et al 313 determined the amount of the IONPs in mice organs, 14 and 580 days after injection, and showed the complete clearance of the IONPs after 580 days. Note that this report only showed the results 14 and 580 days after injection without any intermediate time points and therefore the exact clearance time cannot be exactly established.…”

Fluorescence imaging and targeted distribution of bacterial magnetic particles in nude mice

“…BMPs are 30-50 nm in diameter and have a zeta potential of −24.4± 4.0 mV (Sun et al 2009), which should theoretically facilitate uptake by liver (Xu et al 2009). However, as BMPs tend to agglomerate via magnetic polarity, the size of clumps might be >50 nm, resulting in uptake by other organs (Raynal et al 2004;Tate et al 2011). Such organspecific distribution could be advantageous for use of BMPs as drug carriers in targeted therapy for diseases of the lungs or liver, but disadvantageous for diseases of other organs.…”

Biodistribution and imaging of fluorescently-tagged iron oxide nanoparticles in a breast cancer mouse model

“…Even with this, a pre-injection image is useful to determine background concentrations, especially in the abdominal region where even specially-formulated rodent chow for fluorescent imaging provides some background signal. Accurate quantification of fIONP in abdominally-located organs such as the liver and spleen is crucial to assessing fIONP biodistribution, as IONP have been shown to accumulate largely in the reticuloendothelial system ( 5, 6 ). The overall background will necessarily change over time with tissue scattering and as nanoparticle and fluorophore degrade.…”