Technetium-99m and ICG-labeled HPG (hyperbranched polyglycerol) as a SPECT/FL dual imaging nanoprobe for imaging blood cells: in vitro investigation using myelogenous leukemia cells

This study aimed to develop a single photo emission computed tomography/fluorescence (SPECT/FL) bimodal imaging probe to image blood cells. Hyperbranched polyglycerol (HPG) was synthesized by anionic ring-opening polymerization. Succinic anhydride was used to functionalize HPG. Then, indocyanine green (ICG) was bound to HPG, with a 73.59% binding yield. Deferoxamine (DFO) was subsequently bound to ICG-HPG, and DFO-ICG-HPG was radiolabeled with technetium-99m, with 100% yield. The molecular weight of HPG in this study was found to be 6.8 kDa. In in vitro studies, the radiolabeled nanoconjugates remained stable even after 6 h (last timepoint when stability was assessed), and when the nanoconjugates were applied to K562 chronic myeloid leukemia cells, the highest cell viability was observed at a concentration of 5 mu g/mL and binding efficiency increased over time, reaching 30% at 6 h (last timepoint when binding efficiency was assessed). The results support the feasibility of the developed probe to image blood cells, which would be useful for applications such as detecting internal bleeding. [GRAPHICS] .