MMP2 and bacterial infectious disease: After exposure to MMP‐2 at the bacterial infection site, MPD‐1 disassembled into MNPs and Gd3+, and the r2/r1 ratio was decreased from 46.14 to 2.33, suggesting the switchable properties of MPD‐1 from T2 to T1‐weighted imaging owing to its response toward MMP‐2.