Gadolinium- and Manganite-Based Contrast Agents with Fluorescent Probes for Both Magnetic Resonance and Fluorescence Imaging of Pancreatic Islets: A Comparative Study
Abstract
Three magnetic resonance (MR)/fluorescence imaging probes were tested for visualization, cellular distribution, and survival of labeled pancreatic islets invitro and following transplantation. As T(1) contrast agents (CAs), gadolinium(III) complexes linked to β-cyclodextrin (Gd-F-βCD) or bound to titanium dioxide (TiO2@RhdGd) were tested.
As a T(2) CA, perovskite manganite nanoparticles (LSMO@siF@si) were examined. Fluorescein or rhodamine was incorporated as a fluorescent marker in all probes.
Islets labeled with gadolinium(III) CAs were visible as hyperintense spots on MR invitro, but detection invivo was inconclusive. Islets labeled with LSMO@siF@si CA were clearly visible as hypointense spots or areas on MR scans invitro as well as invivo.
All CAs were detected inside the islet cells by fluorescence. Although the vitality and function of the labeled islets was not impaired by any of the tested CAs, results indicate that LSMO@siF@si CA is a superior marker for islet labeling, as it provides better contrast enhancement within a shorter scan time.