Activatable cell-penetrating peptide (ACPP) conjugated polymeric nanoparticles containing gadolinium (Gd)-chelates and aggregation-induced emission fluorogens (AIEgens) have been synthesized and applied as a magnetic resonance imaging (MRI) and fluorescence imaging (FI) bimodal imaging probe with active tumor targeting. The polymeric nanoparticles have been generated by dissolving presynthesized linear block copolymers into water directly. With AIEgens, N-BP5-Gd-ACPPs showed tumor cell penetration, which can be characterized by in vitro FI. Preliminary in vivo experiments of Gd-chelated nanoparticles have demonstrated promising characteristics as a tumor-targeting MRI contrast agent with good biocompatibility. This study impacts the synthesis of functional copolymers and polymeric nanoparticles for their applications in bioimaging.
Keywords: activatable cell-penetrating peptides; aggregation-induced emission; fluorescence imaging; magnetic resonance imaging; polymeric nanoparticles; tumor targeting.