title: Developing hyperpolarized silicon particles for in vivo MRI targeting of ovarian cancer.
abstract: Silicon-based nanoparticles are ideally suited for use as biomedical imaging agents due to their biocompatibility, biodegradability, and simple surface chemistry that facilitates drug loading and targeting. A method of hyperpolarizing silicon particles using dynamic nuclear polarization, which increases magnetic resonance imaging signals by several orders-of-magnitude through enhanced nuclear spin alignment, has recently been developed to allow silicon particles to function as contrast agents for in vivo magnetic resonance imaging. The enhanced spin polarization of silicon lasts significantly longer than other hyperpolarized agents (tens of minutes, whereas [Formula: see text] for other species at room temperature), allowing a wide range of potential applications. We report our recent characterizations of hyperpolarized silicon particles, with the ultimate goal of targeted, noninvasive, and nonradioactive molecular imaging of various cancer systems. A variety of particle sizes (20 nm to [Formula: see text]) were found to have hyperpolarized relaxation times ranging from [Formula: see text] to 50 min. The addition of various functional groups to the particle surface had no effect on the hyperpolarization buildup or decay rates and allowed in vivo imaging over long time scales. Additional in vivo studies examined a variety of particle administration routes in mice, including intraperitoneal injection, rectal enema, and oral gavage.
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Cancer Systems Imaging, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Whiting
authors.affiliation: University of Texas MD Anderson Cancer Center, Department of Cancer Systems Imaging, 1515 Holcombe Boulevard, Houston, Texas 77030, United States; Rice University, Department of Bioengineering, 6100 Main Street, Houston, Texas 770005-1892, United States.
authors.forename: Jingzhe
authors.initials: J
authors.lastname: Hu
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Cancer Systems Imaging, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Niki M
authors.initials: NM
authors.lastname: Zacharias
authors.affiliation: University of Texas Health Science Center at Houston , Department of NanoMedicine and Biomedical Engineering and the Institute of Molecular Medicine, 7000 Fannin, Houston, Texas 77030, United States.
authors.forename: Ganesh L R
authors.initials: GL
authors.lastname: Lokesh
authors.affiliation: University of Texas Health Science Center at Houston , Department of NanoMedicine and Biomedical Engineering and the Institute of Molecular Medicine, 7000 Fannin, Houston, Texas 77030, United States.
authors.forename: David E
authors.initials: DE
authors.lastname: Volk
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Gastrointestinal Medical Oncology, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: David G
authors.initials: DG
authors.lastname: Menter
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Gynecologic Oncology and Reproductive Medicine, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Rajesha
authors.initials: R
authors.lastname: Rupaimoole
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Gynecologic Oncology and Reproductive Medicine, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Previs
authors.affiliation: University of Texas MD Anderson Cancer Center, Department of Gynecologic Oncology and Reproductive Medicine, 1515 Holcombe Boulevard, Houston, Texas 77030, United States; University of Texas MD Anderson Cancer Center, Center for RNA Interference and Non-Coding RNA, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Sood
authors.affiliation: University of Texas MD Anderson Cancer Center , Department of Cancer Systems Imaging, 1515 Holcombe Boulevard, Houston, Texas 77030, United States.
authors.forename: Pratip
authors.initials: P
authors.lastname: Bhattacharya
keywords: hyperpolarization; magnetic resonance imaging; molecular imaging; silicon nanoparticles