Biodistribution of Multimodal Gold Nanoclusters Designed for Photoluminescence-SPECT/CT Imaging and Diagnostic

Abstract

Highly biocompatible nanostructures for multimodality imaging are critical for clinical diagnostics improvements in the future. Combining optical imaging with other techniques may lead to important advances in diagnostics. The purpose of such a system would be to combine the individual advantages of each imaging method to provide reliable and accurate information at the site of the disease bypassing the limitations of each. The aim of the presented study was to evaluate biodistribution of the biocompatible technetium-99m labelled bovine serum albumin–gold nanoclusters (99mTc-BSA-Au NCs) as photoluminescence-SPECT/CT agent in experimental animals. It was verified spectroscopically that radiolabelling with 99mTc does not influence the optical properties of BSA-Au NCs within the synthesized 99mTc-BSA-Au NCs bioconjugates. Biodistribution imaging of the 99mTc-BSA-Au NCs in Wistar rats was performed using a clinical SPECT/CT system. In vivo imaging of Wistar rats demonstrated intense cardiac blood pool activity, as well as rapid blood clearance and accumulation in the kidneys, liver, and urinary bladder. Confocal images of kidney, liver and spleen tissues revealed no visible uptake indicating that the circulation lifetime of 99mTc-BSA-Au NCs in the bloodstream might be too short for accumulation in these tissues. The cellular uptake of 99mTc-BSA-Au NCs in kidney cells was also delayed and substantial accumulation was observed only after 24-h incubation. Based on our experiments, it was concluded that 99mTc-BSA-Au NCs could be used as a contrast agent and shows promise as potential diagnostic agents for bloodstream imaging of the excretory organs in vivo.

Magnetic Nanoparticles Decorated with Gold Nanoclusters–Applications in Cancer Theranostics

“…We showed that our tested concentrations of MN-AuNCs had no dark cytotoxicity to MCF-7, MDA-MB-231, and NIH3T3 cell lines (Figure 5). These results are also supported by our previous publications, in which blood plasma stabilized gold nanoclusters [17] and technetium-99m labeled bovine serum albumin-gold nanoclusters, [59] at nearly ten and six times higher concentrations, respectively, had almost no cytotoxicity after 24 h of incubation. [17] In another study, which included magnetic nanoparticles combined with gold nanoclusters, slight cytotoxicity to 293T cells appeared using a 0.1 mg mL −1 concentration (which is 25 times lower than the concentration we used), but cell viability still remained above 80%.…”

Biological Interaction and Imaging of Ultrasmall Gold Nanoparticles

“…The ultrasmall AuNPs with high atomic number of Au (Z = 79) show excellent absorbers of X-rays and can offer excellent improvements in CT imaging [ 209 , 210 ]. Furthermore, the surface of ultrasmall AuNPs can be functionalized to couple with other contrast agents (e.g., Gd 3+ , perfluorocarbon, 198 Au and 64 Cu) to generate multimodal imaging capabilities such as magnetic resonance imaging (MRI) [ 211 ], single-photon emission computed tomography (SPECT) [ 212 ] and positron emission tomography (PET) [ 213 , 214 ].…”