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Abstract #1636

Anti-HER2 Antibody and ScFv of EGFR Conjugated Stealth Magnetic Iron Oxide Nanoparticles for Targeting and Magnetic Resonance Imaging of Breast Cancer

Hongwei Chen1, 2, Qiqi Yu1, 2, Liya Wang1, 2, Weiping Qian3, Zehong Cao3, Lily Yang3, Hui Mao1, 2

1Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States; 2Center for Systems Imaging, Emory University School of Medicine, Atlanta, GA, United States; 3Surgery, Emory University, Atlanta, GA, United States

Magnetic iron oxide nanoparticles (IONPs) coated with block copolymer poly(ethylene oxide)-block-poly(-methacryloxypropyltrimeth oxysilane) (PEO-b-PMPS) that exhibit a long blood circulation time (t1/2 = 12 h) in mice and low accumulation in both the liver and spleen. Conjugation of a HER2 antibody, or a single chain fragment (scFv) of antibody against epidermal growth factor receptor (scFvEGFR) to PEO-b-PMPS coated IONPs (anti-HER2-IONPs or scFvEGFR-IONPs) results in HER2 or EGFR-targeted IONPS which specifically bind to HER2 over-expressing breast cancer cell line SK-BR-3 or EGFR positive MDA-MB-231 cells. Both antibody-conjugated and non-conjugated IONPs avoid non-specific uptake by mouse macrophages In Vitro. Magnetic resonance imaging (MRI) of the mice bearing EGFR positive human breast cancer xenografts 24 h after systemic administration of scFvEGFR-IONPs led to signal reduction in tumors as the result of accumulation of the targeted IONPs and IONP induced transverse relaxation T2 weighted contrast.