Gold Nanoparticles Decorated With Octreotide For Somatostatin Receptors Targeting

Targeted drug delivery systems increase the accumulation of medication in the targeted tissues. In contrast, they reduce the relative concentration of medication in non-targeted tissues and inhibit the non-specific distribution to both liver and spleen. The aim of this study is to formulate nanoparticles that are selectively capable of reaching specific sites in the human body via receptors for either diagnostic or therapeutic purposes. These nanoparticles were loaded with octreotide (OCT) which are carried to somatostatin receptor cells. The formulated nanoparticles were characterized by dynamic light scattering (DLS) and UV-VIS spectroscopy. The cellular uptake of the formulated gold nanoparticles (AuNPs-OCT) were studied on cell line with well-expressed somatostatin receptors using inductively coupled plasma optical emission spectroscopy (ICP-OES). The results of DLS showed a successful coating of OCT on the AuNPs, since the average diameter of the AuNPs was increased uniformly. Additionally, the inversion of the zeta potential sign is a further indicator for successful attachment of OCT. The UV-VIS absorption spectra showed a red shift in the surface plasmon resonance peak of AuNPs-OCT compared to unmodified AuNPs. Furthermore, ICP-OES results showed that the counted number of AuNPs-OCT particles per cell is significantly higher than that in case AuNPs-citrate and AuNPs-OCT in the presence of antagonists. Interistingly, it has been observed that the number of particles decreased hugely to the extent which is similar to unmodified AuNPs upon addition of antagonist. The obtained results indicated that the binding of modified nanoparticles to cells is due to differences in surface properties and not to differences in size.