Silica-Coated Europium-Doped Gadolinium Oxide Nanorods for Dual-Modal Imaging of Cancer Cells

Abstract

Dual-modal imaging of cancer cells is possible with the silica-coated europium-doped gadolinium oxide nanorods due to their magnetic and luminescent properties. In the synthesized nanorods, europium ions serve as 'luminescent centers' facilitating optical imaging and gadolinium oxide acts as the contrast agent for magnetic resonance imaging (MRI). This article reports the synthesis method of the europium-doped gadolinium oxide (Eu:Gd2O3) nanorods by the co-precipitation method. The prepared nanorods are further coated with silica to improve its biocompatibility. From the x-ray difraction (XRD) data, the crystallinity was found to decrease due to the amorphous nature of the silica. Transmission electron microscopy (TEM) studies show that Eu:Gd2O3 nanorods with a length of ∼600nm and diameter of ∼40nm were formed. Silica was coated uniformly with the thickness of ∼15nm. Fourier transform infrared spectroscopy (FTIR) confirms the presence of silica in the prepared nanorods. Emission at 611nm due the presence of Eu3+ ions was observed. The life time of uncoated and silica-coated nanorods was calculated to be 1.1ms and 0.9ms, respectively. In vitro cytotoxicity of the synthesized nanorods in MG63 (human osteosarcoma cell line) was assessed by MTT assay. In vitro MRI studies reveal that the prepared nanorods can be used for T1 contrast enhancement.