Mn-based 2D layered nanomaterials for boosting the MRI signal.

• Mn-based LDH with Mn2+ and Mn3+ mixture was obtained under ambient conditions. • Uncovered OH groups surrounding Mn were favorable for proton/water exchange. • Improved r 1 relaxivity as compared with alike Mn-based contrast agents was obtained. Manganese-based 2D nanoparticles with increased longitudinal relaxivity (r 1) in MRI were synthesised by co-precipitation at low suprasaturation. The results of physico-chemical characterizations, i.e., XRD, FT-IR, DR UV–vis, N 2 physisorption, and SEM, showed an excellent 2D nanomaterial in which manganese is predominantly incorporated as Mn2+ and Mn3+. The r 1 relaxivity obtained on a 1.0 Tesla apparatus at pH = 7.4 is significantly improved (r 1 = 1.298 mM−1 s−1) as compared with other similar layered materials containing manganese. [ABSTRACT FROM AUTHOR]