TY - JOUR
T1 - Hyperpolarization of Silicon Nanoparticles with TEMPO Radicals
AU - Hu, Jingzhe
AU - Whiting, Nicholas
AU - Bhattacharya, Pratip
N1 - Funding Information:
*E-mail: pkbhattacharya@mdanderson.org; phone: 1-713-745-0769; fax: 1-713-794-5456. ORCID Nicholas Whiting: 0000-0003-2306-4982 ∥Departments of Physics & Astronomy and Molecular & Cellular Biosciences, Rowan University, Glassboro, NJ 08028 Author Contributions §J.H. and N.W. contributed equally to the work. Funding This work was funded by the MDACC Odyssey Postdoctoral Fellowship, NCI R25T CA057730, DoD PC131680, CPRIT Grant RP150701, MDACC Institutional Research Grants, MDACC Institutional Startup, NCI U54 CA151668, P50 CA083639, NCI R21 CA185536, John S. Dunn Foundation Collaborative Research Award administered by the Gulf Coast Consortia, and NCI Cancer Center Support Grant CA016672. Notes The authors declare no competing financial interest.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/5/17
Y1 - 2018/5/17
N2 - Silicon-based particles can be hyperpolarized via dynamic nuclear polarization to enhance 29Si magnetic resonance signals. Application of this technique to nanoscale silicon particles has been limited because of the low signal enhancements achieved; it is hypothesized that this is due to the low number of endogenous electronic defects inherent to the particles. We introduce a method of incorporating exogenous radicals into silicon nanoparticle suspensions in order to improve the hyperpolarization of 29Si nuclear spins to levels sufficient for in vivo MR imaging. Calibration of radical concentrations and polarization times are reported for a variety of silicon particle sizes (30-200 nm in diameter), with optimal radical concentrations of 30-60 mM. Addition of the radical slightly affects the T1 relaxation of the nanoparticles; however, these losses in T1 are overcome by the overall improvement in 29Si magnetization. With optimal amounts of the added radical, 29Si T1 times are ∼20 min, and MR images in phantoms can be achieved over an hour after hyperpolarization. Co-registered 1H/29Si MR imaging of nanoparticles administered to a mouse model is also presented.
AB - Silicon-based particles can be hyperpolarized via dynamic nuclear polarization to enhance 29Si magnetic resonance signals. Application of this technique to nanoscale silicon particles has been limited because of the low signal enhancements achieved; it is hypothesized that this is due to the low number of endogenous electronic defects inherent to the particles. We introduce a method of incorporating exogenous radicals into silicon nanoparticle suspensions in order to improve the hyperpolarization of 29Si nuclear spins to levels sufficient for in vivo MR imaging. Calibration of radical concentrations and polarization times are reported for a variety of silicon particle sizes (30-200 nm in diameter), with optimal radical concentrations of 30-60 mM. Addition of the radical slightly affects the T1 relaxation of the nanoparticles; however, these losses in T1 are overcome by the overall improvement in 29Si magnetization. With optimal amounts of the added radical, 29Si T1 times are ∼20 min, and MR images in phantoms can be achieved over an hour after hyperpolarization. Co-registered 1H/29Si MR imaging of nanoparticles administered to a mouse model is also presented.
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U2 - 10.1021/acs.jpcc.8b00911
DO - 10.1021/acs.jpcc.8b00911
M3 - Article
AN - SCOPUS:85046422616
SN - 1932-7447
VL - 122
SP - 10575
EP - 10581
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 19
ER -