Table 1.

Manganese-based hybrid nanomaterials as imaging agents.

Agent name	Description	Tumor model	Research group and reference
Mn-NEB+BSA	As dual-modal MRI contrast agents, Mn-NEB+BSA could greatly eliminate suspicious artifacts and false-positive signals in mouse brain imaging.	U87MG tumor-bearing athymic nude mice	Jinhao Gao and Xiaoyuan Chen’s group (28)
DMNF	DMNF showed high tumor-specific MRI with enhanced T1-weighted imaging effect, which was attributed to the synergistic effect of active targeting of AS1411 aptamer and acid-activated release of Mn2+ promoting the MR signal enhancement.	MCF-7 tumor-bearing BALB/c nude mice	Dayong Yang’s group (27)
HMS	Hollow manganese silicate (HMS) nanoparticles could release Mn2+ in physiological acidic condition as a liver-specific MR contrast agent in hepatic tumor models.	HCC, NEC, and ADC tumor-bearing nude mice	Won Jae Lee and In Su Lee’s group (14)

Mn, manganese; NEB, 1,4,7-triazacyclononane-N, N’, N’’-triacetic acid conjugated truncated Evans blue; BSA, bovine serum albumin; DMNF, DNA-Mn-based nanoflower; HMS, hollow manganese silicate.