Candice Brannen PhD, Presenter: Nothing to Disclose

Joseph DeSimone PhD, Abstract Co-Author: Co-founder, Liquida Technologies Inc Stockholder, Liquida Technologies Inc Board of Directors, Liquida Technologies Inc

Weili Lin PhD, Abstract Co-Author: Nothing to Disclose

Kevin Herlihy, Abstract Co-Author: Nothing to Disclose

Hongyu An DSc, Abstract Co-Author: Nothing to Disclose

Recent advances in imprint lithography have merged the precision and uniformity associated with the microelectronics industry with organic chemistry to yield an engineering-based alternative for the fabrication of monodisperse, organic, nanometer sized particles having specific chemical functionality and tailored mechanical properties allowing for the precise control over particle size, shape, composition, cargo, modulus and surface properties for applications in nano-medicine. The goal of the work is to demonstrate effective encapsulation of MR contrast agents within our particles and to assess the feasibility of using these nanoparticles for in vivo imaging.

200 nm PRINT particles composed of PEG matrices were loaded with variable amounts of two different contrast agents; 0.01, 0.1, 1.0, 10, 25 wt% of superparamagnetic iron oxide and 1, 5, 10, 15, and 20 wt% of superparamagnetic gadolinium oxide. The relaxivities were measured using MR. T1 and T2 weighted images were collected and the relaxivities were determined.

Two different contrast agents were investigated: iron oxide and gadolinium oxide. As the concentration of iron oxide within the particles was increased the relaxivity, r2, increased which resulted in a hypointense (dark) signal as compared to water alone. As the concentration of gadolinium oxide was increased, the r1 value increased which resulted in a hyperintense signal (brighter) compared to water. But as the concentration of gadolinium oxide was increased, the r2 value was constant, but larger than that of water which resulted in a darkening or hypointense signal.

The results demonstrate the ability to load PRINT nanoparticles with contrast agents at variable concentrations to obtain MR images.

New MR contrast agents to follow the biodistribution of nanoparticles as a function of size, modulus and surface properties as well as the ability to obtain clearer images of inflammation and tumors.

Brannen, C, DeSimone, J, Lin, W, Herlihy, K, An, H, Enhanced Imaging Using PRINT Nanoparticles with Encapsulated Gadolinium Oxide and Iron Oxide.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5010806.html