Gadolinium (Gd) based contrast agents (CAs) (Gd-CAs) represent one of the most advanced developments in the application of Gd for magnetic resonance imaging (MRI). Current challenges with existing CAs generated an urgent requirement to develop multimodal CAs with good biocompatibility, low toxicity, and prolonged circulation time. This review discussed the Gd-CAs used in bioimaging applications, addressing their advantages and limitations. Future research is required to establish the safety, efficacy and theragnostic capabilities of Gd-CAs. Nevertheless, these Gd-CAs offer extraordinary potential as imaging CAs and promise to benefit bioimaging applications significantly.
Surface-coating polymers contribute to nanoparticle-based magnetic resonance imaging (MRI) contrast agents because they can affect the relaxometric properties of the nanoparticles. In this study, polyaspartic acid (PASA)-coated ultrasmall Gd2O3 nanoparticles with an average particle diameter of 2.0 nm were synthesized using the one-pot polyol method. The synthesized nanoparticles exhibited r1 and r2 of 19.1 and = 53.7 s−1mM−1, respectively, (r1 and r2 are longitudinal and transverse water–proton spin relaxivities, respectively) at 3.0 T MR field, approximately 5 and 10 times higher than those of commercial Gd-chelate contrast agents, respectively. The T1 and T2 MR images could be obtained due to an appreciable r2/r1 ratio of 2.80, indicating their potential as a dual-modal T1 and T2 MRI contrast agent.
Ultrasmall nanoparticles are potential candidates for application as high-performance imaging agents. Herein, we present the synthesis and characterization of folic acid (FA)-conjugated polyacrylic acid (PAA)-coated MnO nanoparticles with an average particle diameter of 2.7 nm. FA conferred cancer-targeting ability, while PAA conferred good colloidal stability and low cellular cytotoxicity on the FA-PAA-coated MnO nanoparticles. Further, the nanoparticles exhibited a high relaxivity (r1) value of 9.3 s−1mM−1 (r2/r1 = 2.2). Their application potential as cancer-targeting T1 magnetic resonance imaging contrast agents was confirmed by their enhanced T1 contrast enhancements at the brain cancer (U87MG) site upon intravenous administration to mice tails.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.