title: Bismuth@US-tubes as a Potential Contrast Agent for X-ray Imaging Applications.
abstract: The encapsulation of bismuth as BiOCl/Bi2O3within ultra-short (ca. 50 nm) single-walled carbon nanocapsules (US-tubes) has been achieved. The Bi@US-tubes have been characterized by high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Bi@US-tubes have been used for intracellular labeling of pig bone marrow-derived mesenchymal stem cells (MSCs) to show high X-ray contrast in computed tomography (CT) cellular imaging for the first time. The relatively high contrast is achieved with low bismuth loading (2.66% by weight) within the US-tubes and without compromising cell viability. X-ray CT imaging of Bi@US-tubes-labeled MSCs showed a nearly two-fold increase in contrast enhancement when compared to unlabeled MSCs in a 100 kV CT clinical scanner. The CT signal enhancement from the Bi@US-tubes is 500 times greater than polymer-coated Bi2S3nanoparticles and several-fold that of any clinical iodinated contrast agent (CA) at the same concentration. Our findings suggest that the Bi@US-tubes can be used as a potential new class of X-ray CT agent for stem cell labeling and possibly in vivo tracking.
authors.affiliation: Department of Chemistry, Smalley Institute for Nanoscale Science and Technology MS-60, P. O. Box 1892, Rice University, Houston TX 77251-1892, USA.
authors.forename: Eladio J
authors.initials: EJ
authors.lastname: Rivera
authors.forename: Lesa A
authors.initials: LA
authors.lastname: Tran
authors.forename: Mayra
authors.initials: M
authors.lastname: Hernández-Rivera
authors.forename: Diana
authors.initials: D
authors.lastname: Yoon
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
authors.forename: Irene A
authors.initials: IA
authors.lastname: Rusakova
authors.forename: Benjamin Y
authors.initials: BY
authors.lastname: Cheong
authors.forename: Maria da Graça
authors.initials: MD
authors.lastname: Cabreira-Hansen
authors.forename: James T
authors.initials: JT
authors.lastname: Willerson
authors.forename: Emerson C
authors.initials: EC
authors.lastname: Perin
authors.forename: Lon J
authors.initials: LJ
authors.lastname: Wilson