Gellan gum-based gels with tunable relaxation properties for MRI phantoms

The research follows the analysis of gellan gum-based gels as novel MRI phantom material with the implementation of a design of experiments model to obtain tunable relaxation properties.

Gellan gum gels doped with newly synthesized superparamagnetic iron oxide nanoparticles (SPIONs) and either MnCl₂ or GdCl₃ were prepared and scanned from 230 μT to 3 T. Nineteen gel samples were formulated with varying concentrations of contrast agents to determine the linear, quadratic, and interactive effects of the contrast agents by a central composite design of experiment. To inhibit microbial growth in the gels and to enable long-term use, methyl 4‑hydroxybenzoate (methylparaben) was utilized.

The model containing SPIONs and metal salts relaxivity was analyzed with ANOVA, and the resulting significant coefficients were tabulated. The mathematical model was able to accurately predict the intended relaxation property from the concentration of the contrast agent with adjusted R² values > 0.97 for longitudinal (R₁) relaxation rates and 0.87 for transverse (R₂) relaxation rates.

The gel material maintained physical, chemical, and biological stability for at least four months and contained controllable relaxation properties while maintaining optical clarity.