Particle Size, Surface Coating, and PEGylation Influence the Biodistribution of Quantum Dots in Living Mice

Abstract

This study evaluates the influence of particle size, PEGylation, and surface coating on the quantitative biodistribution of near-infrared-emitting quantum dots (QDs) in mice. Polymer- or peptide-coated 64Cu-labeled QDs 2 or 12 nm in diameter, with or without polyethylene glycol (PEG) of molecular weight 2000, are studied by serial micropositron emission tomography imaging and region-of-interest analysis, as well as transmission electron microscopy and inductively coupled plasma mass spectrometry. PEGylation and peptide coating slow QD uptake into the organs of the reticuloendothelial system (RES), liver and spleen, by a factor of 6–9 and 2–3, respectively. Small particles are in part renally excreted. Peptide-coated particles are cleared from liver faster than physical decay alone would suggest. Renal excretion of small QDs and slowing of RES clearance by PEGylation or peptide surface coating are encouraging steps toward the use of modified QDs for imaging living subjects.

Targeting kidney mesangium by nanoparticles of defined size

“…The glomerular filtration apparatus, taken in its entirety, possesses an effective size cutoff of 10 nm, and it is responsible for the rapid renal clearance of small nanoparticles. Many nanoparticle-based contrasting agents for in vivo imaging were designed to be smaller than this size cutoff (11,12). Prolonged residency of nanoparticles in the kidney has been shown to induce toxicity in the form of cell shrinkage because of excessive nanoparticle uptake by renal cells (13,14).…”

Gold nanoclusters as novel optical probes for in vitro and in vivo fluorescence imaging

“…Lifetime maps were calculated by determining the lifetime from the fluorescence decays of all the photon counts registered for each pixel. Scale bar 10 μm (Linkov et al 2008;Schipper et al 2009). Recently, Zheng et al (2011) studied renal clearance of glutathione-coated luminescent AuNCs and revealed that only 3.7 % of the clusters accumulated in the liver; over 50 % of the clusters were found in urine within 24 h after intravenous injection, which is comparable to the quantum dots with the best renal clearance efficiency (Soo Choi et al 2007).…”

Radiolabelled Nanoparticles for Diagnosis and Treatment of Cancer

“…A few other reports have focused on radiolabeling QDs with PET isotopes such as 18 F (t1/2: 110 min) and 64 Cu. [48][49][50] However, neither incorporation of a targeting moiety nor optical imaging was carried out in these studies. Due to the difficulties in quantifying the fluorescence signal in vivo and many other technical challenges which remain to be solved, in vivo imaging of QDs is so far mostly qualitative or semiquantitative.…”