Acute Toxicity Evaluation of Glycosylated Gd³⁺-Based Silica Nanoprobe

Early stage diseases diagnosed using magnetic resonance imaging (MRI) techniques is of high global interest as a potent noninvasive modality. MRI contrast agents are improved through modifications in structural and physicochemical properties of the applied nanoprobes. But, the potential toxic effects of nanoprobes upon exposure to biological systems are still a major concern.

In this study, the acute toxicity of glycosylated Gd³⁺-based silica mesoporous nanospheres (GSNs) as a MRI contrast agent was evaluated in Balb/c mice. In order to evaluate in vivo toxicity of GSN, preclinical studies, daily weight monitoring, hematological/blood chemistry tests, and histological assessment were conducted. Magnetic resonance relaxivities of GSN was determined using a MRI scanner.

The obtained results suggest that in vivo toxicity of GSN was mostly influenced by nanoparticle surface area, functionality, and nanoparticle zeta potential. The maximum tolerated dose (MTD) increased in the following order: mesoporous silica nanospheres (MSNs) at 1 mg/mice < GSN (aspect ratio 1, 2, 8) at 40 mg/mice. The results also indicate GSN, one of the best cell imaging contrast agent, which does not show any significant toxicity on multiple vital organs following injection of 20 mg/mice, while a significant T₁-weighted enhancement was observed in whole body of a Balb/c mice 15 min postinjection of (5 μmol/kg) of body weight of GSN.

These results shed light on the functionality of MSNs to minimize in vivo toxicity. Also, glyconanoprobe can be beneficially used for nanomedicine and cellular imaging applications without any significant toxicity.