Tumor-Targeted and Clearable Human Protein-Based MRI Nanoprobes.

Biocompatibility, targeting, and clearance are key challenges in the design of new MRI contrast agents. Herein, we report on a tumor-targeting, gadolinium biomineralized human transferrin (Tf) protein-based nanoparticle (Gd@Tf NP) for MRI use. As compared to the conventionally used gadolinium chelates, the resultant Gd@Tf NPs possess outstanding chemical stability and exhibited superior longitudinal relaxation. More importantly, our MR images show that Gd@Tf indeed retained the natural tumor targeting ability and the subsequent tumor retrieval biofunctions of Tf. Thus, such Tf protein-based MR NPs integrate T1 signal amplification, precise tumor targeting, and systematic clearance capabilities. They offer a new approach to design biocompatible multifunctional MRI contrast agents for a wide range of clinical imaging and treatment applications.