Biomineralization of a rare earth ion (Gd) is first employed to assemble
bovine serum albumin (BSA) into sub-50 nm nanoparticles (
Gd@BSA) for
theranostic applications, via a straightforward and reproducible strategy. Combination of Gd
ions with BSA under mild conditions results in the formation of the
Gd@BSA nanosystem, which has been used as the scaffold material to encapsulate a photosensitiser (Ce6) with high efficiency up to 20 wt%. Beyond playing an important role in the assembled process, the incorporation of Gd affords the potential MRI and fluorescence imaging capability of
Gd@BSA-Ce6 nanoparticles. In vivo MRI allowed real-time imaging in
tumor-bearing mice and showed advantages in terms of circulation time, compared with commercially used
Gd-DTPA.
Gd@BSA-Ce6 nanoparticles exhibited enhanced
tumor-specific distribution, through enhanced permeability and retention effect, and complete cure of
tumor-bearing mice after
intravenous injection. The nanoparticles did not produce systemic toxicity as revealed by biodistribution and histology toxicity analyses. The results demonstrate the great potential of
Gd@BSA-Ce6 nanoparticles as
theranostic agents due to their excellent imaging and
tumor-growth-inhibition properties.