Encapsulated gadolinium and dysprosium ions within ultra-short carbon nanotubes for MR microscopy at 11.75 and 21.1 T.
Single-walled carbon nanotubes (SWNTs) have gained interest for their biocompatibility and multifunctional properties. Ultra-short SWNTs (US-tubes) have demonstrated high proton relaxivity when encapsulating gadolinium ions (Gd(3+)) at clinical field strengths. At higher field strengths, however, Gd(3+) ions demonstrate decreased proton relaxation properties while chemically similar dysprosium ions (Dy(3+)) improve relaxation properties. This report investigates the first use of Gd(3+) and Dy(3+) ions within US-tubes (GNTs and DNTs, respectively) at ultra-high magnetic field (21.1 T). Both agents are compared in solution and as an intracellular contrast agent labeling a murine microglia cell line (Bv2) immobilized in a tissue-mimicking agarose phantom using two high magnetic fields: 21.1 and 11.75 T. In solution at 21.1 T, results show excellent transverse relaxation; DNTs outperformed GNTs as a T(2) agent with measured r(2)/r(1) ratios of 247 and 47, respectively. Additionally, intracellular DNTs were shown to be a better T(2) agent than GNTs with higher contrast percentages and contrast-to-noise ratios. As such, this study demonstrates the potential of DNTs at high magnetic fields for cellular labeling and future in vivo, MRI-based cell tracking.
The National High Magnetic Field Laboratory, The Florida State University, Tallahassee, Florida, USA; Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, The Florida State University, Tallahassee, Florida, USA.
Jens T
JT
Rosenberg
Brandon T
BT
Cisneros
Michael
M
Matson
Michelle
M
Sokoll
Afi
A
Sachi-Kocher
Fabian Calixto
FC
Bejarano
Lon J
LJ
Wilson
Samuel C
SC
Grant
D000818:Animals; D058948:Cell Tracking / Q000379:methods; D003287:Contrast Media; D004419:Dysprosium / Q000737:chemistry; D005682:Gadolinium / Q000737:chemistry; D007477:Ions; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008853:Microscopy / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry*
D003287:Contrast Media; D007477:Ions; D037742:Nanotubes, Carbon; D004419:Dysprosium; D005682:Gadolinium
Bv2 microglia cells; contrast agents; dysprosium; gadolinium; high field MRI; relaxometry; ultra-short carbon nanotubes