Real-time monitoring in vivo behaviors of theranostic nanoparticles by contrast-enhanced T1 imaging.

Abstract

The innovative applications of engineered nanoparticles (NPs) in medicine, such as diagnosis and therapy, have attracted considerable attention. It is highly important to predict the interactions between engineered NPs and the complex biological system as well as the impacts on the subsequent behaviors in living subjects. Herein, we report the use of T1 contrast-enhanced magnetic resonance imaging (MRI) to monitor the in vivo behaviors of NPs in a real-time manner. We chose ultrasmall Pd nanosheets (SPNSs) as the object of NPs because of their promise in theranostics and fitness for diverse surface chemistry. SPNSs were modified with different surface coating ligands (e.g., polyethylene glycol, zwitterionic ligands, polyethylenimine) and functionalized with Gd-chelates to render T1 contrast-enhanced capability. MRI real-time monitoring recorded the location and accumulation of SPNSs in small animals and revealed the prominent roles of surface coating ligands in pharmacokinetics. These results highlighted the significance of selecting proper surface coating for particular biomedical assignment. Moreover, we demonstrated a powerful and noninvasive means to predict and detect the behaviors of NPs in living subjects, which may be helpful for rational design and screening of engineered NPs in biomedical applications.