Dual-mode imaging, which combines optical and magnetic resonance (MR) imaging, as a diagnosis tool for cancer at early-stage has been shown to be particularly attractive because it will allow retrieving both macroscopic and subcellular information of bio-species, and thus leading to improved diagnostic accuracy. To this end, a variety of multifunctional multifunctional (superparamagnetic and photoluminescent) nanoparticles (NPs) have been specifically designed for dual-mode imaging. However, most of these hybrid NPs show shallow tissue penetration and low signal contrast in optical imaging due to the tissue-induced extinction and autofluorescence since their photoluminescent components based on organic dyes, upconversion nanoparticles (UCNPs) and quantum dots (QDs) are operated in the visible range. In this work, we prepare a biocompatible core/shell/shell sandwich structured Fe3O4@SiO2@NaYF4:Nd3+ nanoplatform possessing excellent superparamagnetic and near-infrared (excitation) to near-infrared (emission), i.e., NIR-to-NIR photoluminescence properties. This NIR-to-NIR feature enables deep-tissue penetrated optical imaging with high signal-to-noise ratio which was demonstrated by the ex vivo experiment of chicken samples with thickness of 13 mm. Meanwhile, owing to the superparamagnetic Fe3O4 core inside, this nanoplatform can be rapidly confined under an external magnetic field and exhibited a significant darkening effect in T2-weighted images in MR imaging. More importantly, the developed NPs are much less toxic than semiconductor QDs, which usually contain Pb and/or Cd. These results including excellent photostability, fast magnetic response, significant T2-contrast enhancement and negligible cytotoxicity suggest that Fe3O4@SiO2@NaYF4:Nd3+ nanoplatform can be extremely suitable for use in high resolution, deep-tissue dual-mode (optical and magnetic resonance) imaging in vivo and magnetic-driven applications.

Integrated multifunctional nanoplatform based on superparamagnetism and near-infrared to near-infrared photoluminescence for deep-tissue dual-mode imaging

256th National Meeting (2018)

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