Given contrast-enhanced MRI (CE-MRI) of AKI significantly restricted by the inadequate targeting ability and potential toxicity of existing contrast agents, bovine serum albumin@polydopamine@Fe (BSA@PDA@Fe, BPFe) nanoprobe with self-purification capabilities and renal tubule-targeting properties for targeted CE-MRI of AKI [40]. Here, ALB is linked to acute kidney injury.