LHRH-Conjugated Magnetite Nanoparticles and Nanorods as Magnetic Resonance Imaging Contrast Agents for Targeting...

This paper presents the results of an experimental study on the effects of magnetite nanoparticle (MNP) shape on magnetic resonance imaging (MRI) of triple-negative breast cancer (TNBC) xenograft tissues. T₂-weighted MRI scans using spherical shaped MNPs as contrast agents are compared to MRI scans done with nanorod-shaped MNPs as contrast agents. The MNPs were first coated with polyethylene glycol (PEG) and subsequently conjugated to luteinizing hormone-releasing hormone (LHRH) to specifically target LHRH receptors, which are present at high levels on the surfaces of xenograft TNBC cells/tissues. After 3 weeks of tumor growth in nude immunocompromised mice, LHRH-conjugated (functionalized) and unconjugated (non-functionalized) MNPs were injected into the immunocompromised mice. Four types of MNPs were used: non-functionalized nanorod-shaped MNPs (BMNR); LHRH-conjugated nanorod-shaped MNPs (LCMNR); non-functionalized spherical-shaped MNPs (BSSMNP); and LHRH-conjugated spherical-shaped MNPs (LCSSMNP). T₂-weighted magnetic resonance imaging (MRI) scans were obtained from the mice before the injection of the MNPs and two hours after the injection of the MNPs. The results show that using nanorod-shaped LHRH-conjugate MNPs as contrast agents yielded higher-resolution T₂-weighted MRI scans of TNBC tumors compared to those from spherical-shaped MNPs. The implications of the results are discussed in relation to potential applications of functionalized MNPs in MRI for TNBC diagnosis.