Multifunctional Magnetic Gd3+-Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor-Targeted Imaging in vivo

To overcome traditional barriers in optical imaging and microscopy, optoacoustic-imaging has been changed to combine the accuracy of spectroscopy with the depth resolution of ultrasound, achieving a novel modality with powerful in vivo imaging. However, magnetic resonance imaging provides better spatial and anatomical resolution. Thus, a single hybrid nanoprobe that allows for simultaneous multimodal imaging is significant not only for cutting edge research in imaging science, but also for accurate clinical diagnosis. A core-shell-structured coordination polymer composite microsphere has been designed for in vivo multimodality imaging. It consists of a Fe 3 O 4 nanocluster core, a carbon sandwiched layer, and a carbocyanine-Gd III (Cy-Gd III ) coordination polymer outer shell (Fe 3 O 4 @C@Cy-Gd III ). Folic acid-conjugated poly(ethylene glycol) chains are embedded within the coordination polymer shell to achieve extended circulation and targeted delivery of probe particles in vivo. Control of Fe 3 O 4 core grain sizes results in optimal r 2 relaxivity (224.5 × 10 –3 m −1 s -1 ) for T 2 -weighted magnetic resonance imaging. Cy-Gd III coordination polymers are also regulated to obtain a maximum 25.1% of Cy ligands and 5.2% of Gd III ions for near-infrared fluorescence and T 1 -weighted magnetic resonance imaging, respectively. The results demonstrate their impressive abilities for targeted, multimodal, and reliable imaging.