In this presentation a novel gadolinium-encapsulating iron oxide nanoparticle-based activatable NMR/MRI nanoprobe will be discussed. In this design, Gd-DTPA is encapsulated within the polyacrylic acid (PAA) polymer coating of a superparamagnetic iron oxide nanoparticle (IO-PAA) yielding a composite magnetic nanoprobe (IO-PAA-Gd-DTPA) with quenched longitudinal spin-lattice magnetic relaxation (T1). Upon release of the Gd-DTPA complex from the nanoprobe's polymeric coating in acidic media, an increase in the T1 relaxation rate (1/T1) of the composite magnetic nanoprobe was observed, indicating a dequenching of the nanoprobe with a corresponding increase in the T1-weighted MRI signal. When a folate-conjugated nanoprobe was incubated in HeLa cells, a cervical cancer cell line overexpressing folate receptors, an increase in the 1/T1 signal was observed. This result suggests that upon receptor-mediated internalization, the composite magnetic nanoprobe degraded within the cancer cell's acidic (pH = 5.0) environment, resulting in an intracellular release of Gd-DTPA complex with subsequent T1 activation. Furthermore, when an anticancer drug (Taxol) was co-encapsulated with the Gd-DTPA within the composite magnetic nanoprobe, the T1activation of the probe coincide with the rate of drug release and corresponding cytotoxic effect in cell culture studies. In addition, small molecule-based other activatable fluorescence prodrugs for cancer targeting and treatment will be discussed. Taken together, the importance of activatable optical and MRI probes in cancer imaging will be highlighted in this presentation.References: S. Santra and J. M. Perez et.al. ACS Nano 2012  , 6, 7281.S. Santraand J. M. Perez et.al. JACS 2011  , 133, 16680.

Designer activatable theranostics for cancer targeting

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.