(a) SAIO consists of carbohydrates and iron, which gives it a high level of biocompatibility. 3 nm carbohydrates are coated with iron, giving it a total size of 5 nm. (b) Comparison of performance between SAIO and current contrast agent. SAIO has a 2.5-fold higher MRI signal and a 5-fold longer duration of the contrast effect compared to the current contrast agent. (c) SAIO improves the resolution by up to 10-fold compared to the current contrast agent, enabling clear visualization of objects with a diameter as small as 100 microns.