MNCb, MNRd, and MNCl delivery efficiency for all tumor types was 3.79% ID, 2.94% ID, and 1.21% ID, respectively (two-way ANOVA, p > 0.05).
Next MRI studies were performed to evaluate MNCb, MNRd, and MNCl contrast properties in vivo.
MNCb and MNRd provided detectable tumor signaling in 73% and 63% tumors, respectively (Figures 4-6).
The most profound tumor contrasting corresponded to 6-24 hours after MNCb and MNCl injection, whereas MNRd accumulation in malignancies reached its maximum within first 30 minutes upon i.v.
All studied IONPs had a similar crystallite size of 10-20 nm; however, hD ranged from 65 nm for MNCb to 120 nm for MNRd. It should be noted that maintaining all the other parameters effectively the same and only change the core morphology is impracticable for such different shapes as nanocube and nanorod .
Thus, 24 h after treatment with MNCb, MNRd, and MNCl, liver accumulated 74 [+ or -] 12% ID, 50 [+ or -] 9% ID, and 70 [+ or -] 6% ID and spleen 20 [+ or -] 3% ID, 11 [+ or -] 3% ID, and 21 [+ or -] 4% ID, respectively.
Probably, due to increased half-lives, MNCb and MNCl gradually accumulated in most tumors up to 24 h, resulting in better uptake rates and MRI performance compared with MNRd. The latter demonstrated peak accumulation rates within first 30 minutes after injection without significant increase at later time points.
It should be noted that MNCb hD was lower than that of MNCl and MNRd (see Table 1), so it cannot be ruled out that better MNCb uptake is not only a shape- but also size-dependent phenomenon.
To ensure the safety of studied MNCb, MNRd, and MNCl, we carried on cytotoxicity studies on mice fibroblasts.
In contrast, MNRd low in vitro r2-relaxivity coupled high accumulation in lungs and suboptimal uptake by tumors limited its contrasting efficiency.
Histograms of MNCb (a), MNRd (b), and MNCl (c) size distribution (associated with Figure 1A) Supplementary figure S2.
XRD characteristics of MNCb, MNRd, and MNCl and standard magnetite nanoparticles.