Targeting of Somatostatin Receptors using Quantum Dots Nanoparticles Decorated with Octreotide

Abstract

The main goal of this work was to understand how nanoparticles target specific sites in the body with specific targeting peptides to specific receptor by active targeting. This gives a better understanding of the delivery to the targeted sites with reduced side effects and high drug delivery efficacy. The study focused on the methods of preparation and the characterization of quantum dots (Qdots) carrying a PEG-amine which were first succinylated using succinic anhydride, then conjugated to octreotide, somatostatin analogue (OCT) at low pH at its N-terminus to give Qdots-OCT. This was followed by successful cellular uptake experiments and in vivo studies of the nanoparticles. The results showed a successful characterization for Qdots-conjugated OCT. Cellular uptake showed highly specific interactions with cells using confocal microscopy and flow cytometry. The Qdots-OCT can be displaced from their receptor, which relates to the specificity of the interaction with somatostatin receptor. In vivo study showed a massive accumulation of Qdots- OCT in the blood as compared to the other organs, which may related to the interaction with somatostatin receptor overexpressed on the Monocytes. In conclusion, OCT can deliver the nanoparticles to the targeted sites with high drug delivery efficacy in vitro or even in vivo. Moreover, the high blood circulation of Qdots-OCT nanoparticles could be due to decoration with OCT, which could be bound to somatostatin receptors in blood cells.