Development of sensitive
contrast agents for positive magnetic resonance (MR) imaging of biosystems still remains a great challenge. Herein, we report a facile process to construct hybrid
alginate (AG)
nanogels (NGs) loaded with
manganese oxide (
Mn3O4) nanoparticles (NPs) for enhanced
tumor MR imaging. The obtained AG/PEI-
Mn3O4 NGs with a mean size of 141.6 nm display excellent colloidal stability in aqueous
solution and good cytocompatibility in the studied concentration range. Moreover, the hybrid NGs have a high r1 relaxivity of 26.12 mM-1 s-1, which is about 19.5 times higher than that of PEI-Mn3O4 NPs with PEI surface
amine acetylated (PEI.Ac-Mn3O4 NPs). Furthermore, the AG/PEI-
Mn3O4 NGs presented longer blood circulation time and better
tumor MR imaging performances in vivo than PEI.Ac-Mn3O4 NPs. With the good biosafety confirmed by histological examinations, the developed AG/PEI-
Mn3O4 NGs may be potentially used as an efficient
contrast agent for enhanced MR imaging of different biosystems.