ROS-generation and cellular uptake behavior of amino-silica nanoparticles arisen from their uploading by both iron-oxides and hexamolybdenum clusters

Abstract

The present work introduces combination of superparamagnetic iron oxides (SPIONs) and hexamolybdenum cluster ([{Mo₆I₈}I₆]^2-) units within amino-decorated silica nanoparticles (SNs) as promising design of the hybrid SNs as efficient cellular contrast and therapeutic agents. The heating generated by SNs doped with SPIONs (Fe₃O₄@SNs) under alternating magnetic field is characterized by high specific absorption rate (SAR = 446 W/g). The cluster units deposition onto both Fe₃O₄@SNs and "empty" silica nanoparticles (SNs) results in Fe₃O₄@SNs[{Mo₆I₈}I₆] and SNs[{Mo₆I₈}I₆] with red cluster-centered luminescence and ability to generate reactive oxygen species (ROS) under the irradiation. The monitoring of spin-trapped ROS by ESR spectroscopy technique indicates that the ROS-generation decreases in time for SNs[{Mo₆I₈}I₆] and [{Mo₆I₈}I₆]^2- in aqueous solutions, while it remains constant for Fe₃O₄@SNs[{Mo₆I₈}I₆]. The cytotoxicity is low for both Fe₃O₄@SNs[{Mo₆I₈}I₆] and SNs[{Mo₆I₈}I₆], while the flow cytometry indicates preferable cellular uptake of the former versus the latter type of the nanoparticles. Moreover, entering into nucleus along with cytoplasm differentiates the intracellular distribution of Fe₃O₄@SNs[{Mo₆I₈}I₆] from that of SNs[{Mo₆I₈}I₆], which remain in the cell cytoplasm only. The exceptional behavior of Fe₃O₄@SNs[{Mo₆I₈}I₆] is explained by residual amounts of iron ions at the silica surface.

Keywords: Cellular uptake; Cluster; Iron oxide nanoparticles; Luminescence; ROS-generation; Silica nanoparticles.