Electronic Posters: Cardiovascular

Thursday 13:30-15:30 Computer 40

13:30 3753. A Targeted Nanoglobular Manganese(II) Chelate Conjugate for Magnetic Resonance Cancer Molecular Imaging

Mingqian Tan¹, Eun-Kee Jeong², Zheng-Rong Lu<sup>1

1</sup>Case Western Reserve University, Cleveland, OH, United States; ²University of Utah, Salt Lake City, UT, United States

A peptide targeted nanoglobular Mn(II)-DOTA conjugate was designed and synthesized as MRI contrast agent for cancer molecular imaging. The target specific contrast agent comprised of 2 peptides and 42 Mn(II) chelates on the surface of the G3 nanoglobule with a defined structure. The T1 and T2 relaxivities at room temperature are 3.13 and 8.14 mM-1sec-1 per Mn(II) chelate at 3T, respectively. The targeted nanoglobular contrast agent specifically bound to tumor tissue and resulted in significant tumor contrast enhancement in tumor-bearing mice as compared to a non-targeted control at a dose as low as 0.03 mmol-Mn/kg .

14:00 3754. Multi-Functional Nanocontrast Agents for In Vivo Probing on Non-Small Cell Lung Cancer in MR and Optical Molecular Imaging

Ching-Tang Chen¹, Chia-Hao Su², Yi-Chien Lu¹, Ang Yuan³, Jyh-Horng Chen<sup>1

1</sup>Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan; ²Center for Translational Research in Biomedical Science, Chang Gung Memorial Hospital, Kaohsiung, Taiwan; ³Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Taiwan

Molecular imaging has become an indispensable technology in cancer research and clinical use. The goal of this study is to combine magnetic resonance imaging and optical imaging system with multifunctional contrast agent to detect xenograft non-small cell lung cancer (NSCLC) murine model.

High temperature solution phase reaction led to 8 nm ultrasmall superparamagnetic iron oxide (USPIO, Fe³O⁴), and the CdS-capped CdTe_xSe_1-x alloyed quantum dot was synthesized to near-IR emitting nanoparticles. Aqueous iron oxide and near-IR quantum dot nanoparticles were conjugated with anti-epideremal growth factor receptor (EGFR) antibody as the biomedical probe to detect the NSCLC tumor. Variation of T2 relaxation time was obtained from MRI for nano-contrast agent quantification. Prussian blue staining imaging showed different targeting efficiency in A549 and CL1-0 in vitro. T2 and T2* MR imaging showed significant signal decrease (>30%) in vivo. It was proved caused by nano-probe targeting by using both histological cytochemistry staining. Multifunctional nanocontrast agent could hopefully not only serves as cancer detection and treatment but also used to predict disease prognosis in the future.

14:30 3755. The Use of Cellular MRI and Magnetic Particles to Study Cancer Stem Cells

Emeline Julie Ribot¹, Carmen Simedrea², Patricia McGowan², Ann Chambers², Paula J. Foster<sup>1

1</sup>Imaging Laboratories, Robarts Research Institute, London, Ontario, Canada; ²Medical Biophysics, University of Western Ontario, London, Ontario, Canada

In this abstract, we describe technology developed in our labs for tracking stem-like cancer cells (CSC), in a mouse model of breast cancer metastasis to the brain, using MRI and magnetic particles. A human breast cancer cell line was sorted by flow cytometry into two distinct populations: CD44high/CD24low and CD44low/CD24high, representing the CSC-like and non-CSC cells, respectively. The sorted cell populations can be labeled efficiently and without toxicity with the iron agent MoldayION Rhodamine B. Labeled CSC can be detected in vivo in images of the mouse brain after injection into the left ventricle of the heart in nude mice.

15:00 3756. Development of Cationic Gd(III) Chelate as Potential Tumor-Selective MRI Contrast Agent

Chang-Tong Yang¹, Cai-Xian Yong¹, Chew-Yuan Tuang², Young-Tae Chang², Kai-Hsiang Chuang<sup>1

1</sup>Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore; ²Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore

We developed a new Gd(III) chelate by conjugating GdDO3A with 2-(diphenylphosphoryl)ethyldiphenylphosphonium cation -- Gd(DO3A-xy-TPEP)+ to form a cationic MRI contrast agent. This contrast agent has been synthesized and characterized in vitro and in vivo. In vitro cell viability showed insignificant cytotoxicity at low [Gd] concentrations up to 0.2 mM. The in vitro T1 relaxivity measured at 7.0 T is about 50% higher than that of clinically used Gd-DTPA and Gd-DOTA. In vivo imaging study in mice demonstrated longer tissue retention especially in the liver. It indicated that Gd(DO3A-xy-TPEP)+ could potentially be used to detect tumor which generally has larger negative mitochondrial transmembrane potential.