Table 1.

Relaxivities (s⁻¹mM⁻¹) of nanoparticles as a function of pH and time.

Capping on MnO	r1 pH 7.4 20 min.	r1 pH 5.0 20 min.	r1 pH 5.0 3 days
SiO2	0.29	2.60	6.10
PMAO-PEG	1.79	3.57	6.31
Pluronic PF127	1.91	6.59	6.59
PMAO	2.42	3.38	6.39
MSA	2.55	6.94	6.91