Superparamagnetic polymeric micelles as Uutrasensitive MRI contrast agents

COLL 214

Chalermchai Khemtong, Chalermchai.Khemtong@UTSouthwestern.edu, Harold C. Simmons Comprehensive Cancer Center, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-8807, Jimin Ren, Jimin.Ren@UTSouthwestern.edu, The University of Texas Southwestern Medical Center at Dallas, Advanced Imaging Research Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8568, A. Dean Sherry, Dean.Sherry@UTSouthwestern.edu, Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75390-8568, and Jinming Gao, Jinming.Gao@UTSouthwestern.edu, The University of Texas Southwestern Medical Center at Dallas, Harold C. Simmons Comprehensive Cancer Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8807.
We herein report the preparation and characterization of paramagnetic polymeric micelles as ultrasensitive MRI contrast agents. Hydrophobic MFe2O4 (M = Fe, Co, Mn) nanoparticles were prepared via an organic reaction of corresponding metal acetylacetonates. Transmission electron microscopy (TEM) analysis revealed that the size distribution of nanoparticles were mostly monodispersed. 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy(polyethylene glycol) (DSPE-PEG, PEG MW = 5kD) and poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-PLA, PEG and PLA MW = 5 kD) were used as polymeric surfactants for the formation of MFe2O4-loaded micelles. The micelles were characterized by dynamic light scattering and TEM analyses. MR relaxivity measurements showed that the T2 relaxivity rates (r2 ) of MFe2O4-loaded micelles follow the order CoFe2O4 > MnFe2O4 > Fe3O4. The magnetization measurements of dried MFe2O4 nanoparticles showed that the saturation magnetization (Msat) values of MFe2O4 followed the same trend as the relaxivity values.
 

Advances in Nanomedicine
1:30 PM-5:20 PM, Monday, 11 September 2006 Sir Francis Drake -- Monterey/Cypress Rooms, Oral

Division of Colloid & Surface Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006