The relaxivity of a gadolinium-based contrast agent (GBCA) is a critical parameter that determines the efficacy of a complex as a magnetic resonance imaging (MRI) CA. One strategy to improve the relaxivity is to increase the size of the agent. We thus decided to investigate the effect of oligonucleotide ligands on the relaxation time of gadolinium(III) complexes. These ~40 nucleobase-long strands, when chelated to the ion or complex, serve to significantly modulate the size and rotational motion of the latter. We will report on the in vitro selection and isolation of the oligonucleotide strands, characterization of binding parameter to the Gd(III) moiety, and overall effect on the relaxation time of the assemblies at low and high magnetic field strengths. A markedly improved relaxivity will result in reduced dosage and toxicity of GBCAs, and the findings from this study will furnish valuable insights into the tunability of the longitudinal and transverse relaxation of these agents.

Gadolinium(III) relaxivity modulation via oligonucleotide coordination

2019 Spring National Meeting

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