LAUSR

High-performance magnetic resonance (MR) imaging contrast agents are the key to reliable and accurate diagnosis of diseases using the MR imaging technique. In particular, dual-modal MR imaging nanoprobes that integrated the advantages of a high contrast effect and impressive sensitivity of T1- and T2-weighted MR imaging, respectively, have attracted increasing attention in recent years. However, the current methods for the fabrication of the dual-modal MR imaging nanoprobes suffer from a tedious synthesis procedure, harsh synthesis condition and ambiguous toxicity, strongly hindering their clinic transformation. Herein, we proposed a biomineralization approach for the fabrication of bovine serum albumin (BSA)–Fe3O4 nanoparticles with undoubted biosafety and robust T1 and T2 MR imaging ability in a facile way under mild conditions. BSA not only served as a template to control the growth of nanocrystal, but also enabled the favorable water solubility of the nanoprobe. The outstanding biocompatibility of BSA–Fe3O4 nanoparticles was proven by systematic in vitro and in vivo toxicity assessments, and dual-modal T1 and T2 MR imaging in vivo was achieved successfully. In addition, the nanoprobe was successfully applied for in vivo MR imaging of liver with a broad time window, and the metabolic investigation of BSA–Fe3O4 nanoparticles revealed that they could be eliminated from the body, ensuring a negligible adverse effect. The proposed biomineralization approach opens a new way for the fabrication of dual-modal MR contrast imaging nanoprobe with undoubted biosafety, and other functional proteins also exhibit great potential for the fabrication of dual-modal MR contrast imaging nanoprobe with specific functions with respect to biomineralization.