PET imaging and biodistribution studies with ultrasmall nanoparticles

For the past decade, renally clearable ultrasmall nanoparticles (sub-10 nm size) have attracted enormous attention for biomedical applications[1]. In this direction, ultrasmall silicon nanoparticles (Si NPs) and carbon “quantum” dots (CQDs) are gaining in importance[2, 3]. These quantum-sized particles display tunable photoluminescence, they are highly resistant against photo-bleaching, chemically stable after functionalization and biocompatible. Covalent functionalization of the surface with appropriate bifunctional chelator agents (BFCAs) for radiometals such as 99mTc, 111In, 64Cu, 68Ga enabling SPECT or PET, and simultaneously targeting vector molecules opens the avenue for the development of promising targeted dual-labelled imaging agents.
Here we report on the synthesis and characterization of Si NPs and CQDs (size < 5 nm), containing 64CuII-NOTA for PET imaging. The biodistribution data demonstrate that the 64Cu-labelled particles are rapidly excreted from the body using the renal pathway. In particular, the surface charge of Si NPs and CQDs seems to influence the biodistribution pattern.

Work financially supported by Helmholtz Virtual Institute “Nano-Tracking”, Agreement No. VH-VI-421

[1] B. H. Kim, M. J. Hackett, J. Park, T. Hyeon, Chemistry of Materials 2014, 26, 59-71

[2] Tu, C., X. Ma, A. House, S. M. Kauzlarich, A. Y. Louie, ACS Medicinal Chemistry Letters 2011, 2, 285

[3] Hong, G., S. Diao, A. L. Antaris, H. Dai, Chemical Reviews 2015, 115, 10816–10906