Abstract: Chemotherapy is still a kind of important strategy for cancer treatment, but lacking efective delivery system limits the therapeutic outcome. Owing to the excellent biocompatibility, albumin has been employed as drug vehicle; however, it has to face complicated synthesis procedures and still needs an efective technology for the drug delivery evaluation. In this study, a facile method was utilized to prepare a protein-based theranostic system through the self-assembly of albumins with small molecules and drugs; furthermore, the paramagnetic divalent manganese ions were conjugated on the surface of the nanocomposite through a coordination bond and carried out the magnetic resonance imaging. This nanosystem with a stable structure exhibited about 80 nanometer size and 7.7 [Mn] mM-1S-1 T1 relaxivity; moreover, the pH-sensitive drug releasing property and the imaging function empower it with theranostic cancer therapy. Moreover, the nanocomposites efectively entered into the cancer cells and showed superior antitumor ability; and these treated cells exhibited signifcant T1 signal. These results suggested that the albumin-based nanosystem is a novel chemotherapy drug delivery vehicle and a promising candidate for magnetic resonance imaging.

Key words: Drug delivery system, Magnetic resonance imaging, Theranostic therapy, Self-assembly