Fabrication and evaluation of tumor-targeted positive MRI contrast agent based on ultrasmall MnO nanoparticles

- Tumor-targeted positive MRI contrast agent based on ultrasmall MnO nanoparticles was fabricated.
- The as-fabricated contrast agent showed efficient accumulation behavior in tumor tissue.
- The as-fabricated contrast agent showed a good and long-term effect of enhancing MRI signal and acceptable cytotoxicity.