Folic acid-conjugated Fe-Au-based nanoparticles for dual detection of breast cancer cells by magnetic resonance imaging and computed tomography

Abstract

Abstract

Purpose: We synthesized folic acid-conjugated Fe₃O₄/Au-pralidoxime chloride nanoparticles (Fe-Au-PAM NPs) for use as dual-modal contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of breast cancer.

Methods: Fe-Au-PAMs NPs conjugated or not to folic acid were synthesized and analyzed by dynamic light scattering, transmission electron microscopy, and vibrating sample magnetometry. The ability of these NPs to create image contrast was also investigated in silico and in vitro (in MCF-7 breast cancer cells and A549 lung cancer cells) with CT and MRI.

Results: Dynamic light scattering and transmission electron microscopy revealed that the Fe-Au-PAM NPs were nearly spherical. The average diameter of Fe-Au NPs increased from 11.6 nm to 98 nm after folic acid conjugation. The saturation magnetization values of Fe-Au-PAM NPs with and without folic acid conjugation were 32.6 and 25.6 emu/g, respectively. Conjugation of folic acid to NPs greatly improved their uptake by cancer cells. The additional coating of NPs with Au reduced the T2 relaxation time for MRI from 245 ms for Fe-PAM NPs to 162 ms for Fe-Au-PAM NPs. Folic acid-conjugated NPs had radiodensity measurements of 185.2 Hounsfield units (HU) compared to 153.4 HU for non-conjugated NPs.

Conclusion: Folic acid-conjugated Fe-Au-PAMs NPs can serve as dual CT/MRI contrast agents and improve the sensitivities of both modalities for the detection of cancer cells.

Keywords: Breast Cancer; Computed Tomography; Magnetic Resonance Imaging; Targeted Imaging