Authors: C. Schmidtke, J. Ostermann, H. Tran, E. Pöselt, H. Kloust, J. Niehaus, S. Becker, A. Kreuziger, K. Werner, A. Pietsch, H. Weller
Affilation: University of Hamburg, Germany
Pages: 36 - 39
Keywords: quantum dots, nanoparticles, diblock copolymer, functionalization, phase transfer, imaging, tumor targeting
We would like to present a micellular encapsulation method for nanoparticles (quantum dots, iron oxides, gold) which is based on a ligand exchange procedure of native ligands with a prepolymer poly(isoprene)-diethylentriamine (PI-N3) and subsequent ligand addition with poly(isoprene)-b-poly(ethylene glycol) diblock copolymer (PI-b-PEG). As previously reported ligand systems are usually based on self-organization by hydrophobic effects and/or coordinative bonds. Here, both effects were combined and expanded to include the cross-linkage of the poly(isoprene) moiety. This leads to unique stability in aqueous media with fluorescence quantum efficiencies up to 55% and ensures rigidity against biodegradation. PI-b-PEG diblock copolymer encapsulated NPs are non-toxic and were used for antibody-mediated imaging of tumors in vivo. The use of the diblock copolymer allows the functionalization at different stages: a) prior to the ligand addition by terminating the polymerization or after the polymerization (pre-assembly) and b) after the ligand addition (post-assembly).