Theranostic MUC-1 aptamer targeted gold coated superparamagnetic iron oxide nanoparticles for magnetic resonance imaging and photothermal therapy of colon cancer

• Gold coated SPIONs serve as a self-therapeutic device to eradicate colon cancer.
• Conjugated aptamers efficiently deliver the NPs to the target cell line.
• Protein corona coated SPIONs exhibit lower cytotoxicity compared to bare SPIONs.

Favorable physiochemical properties and the capability to accommodate targeting moieties make superparamegnetic iron oxide nanoparticles (SPIONs) popular theranostic agents. In this study, we engineered SPIONs for magnetic resonance imaging (MRI) and photothermal therapy of colon cancer cells. SPIONs were synthesized by microemulsion method and were then coated with gold to reduce their cytotoxicity and to confer photothermal capabilities. Subsequently, the NPs were conjugated with thiol modified MUC-1 aptamers. The resulting NPs were spherical, monodisperse and about 19 nm in size, as shown by differential light scattering (DLS) and transmission electron microscopy (TEM). UV and X-ray photoelectron spectroscopy (XPS) confirmed the successful gold coating. MTT results showed that Au@SPIONs have insignificant cytotoxicity at the concentration range of 10–100 μg/ml (P > 0.05) and that NPs covered with protein corona exerted lower cytotoxicity than bare NPs. Furthermore, confocal microscopy confirmed the higher uptake of aptamer-Au@SPIONs in comparison with non-targeted SPIONs. MR imaging revealed that SPIONs produced significant contrast enhancement in vitro and they could be exploited as contrast agents. Finally, cells treated with aptamer-Au@SPIONs exhibited a higher death rate compared to control cells upon exposure to near infrared light (NIR). In conclusion, MUC1-aptamer targeted Au@SPIONs could serve as promising theranostic agents for simultaneous MR imaging and photothermal therapy of cancer cells.

Question 2 of Editor: Please provide a BRIEF caption (one sentence) for the graphical abstract. Abbreviations in the picture should be explained.Answer: In receptor positive cells, MUC1 aptamer targeted gold coated superparamagnetic iron oxide nanoparticles (Au@SPIONs) can be used for simultaneous magnetic resonance imaging and near infrared (NIR)-mediated photothermal therapy of colon cancer.Figure optionsDownload as PowerPoint slide