Perylene Diimide-Grafted Polymeric Nanoparticles Chelated with Gd³⁺ for Photoacoustic/T₁-Weighted Magnetic Resonance Imaging-Guided Photothermal Therapy

Developing versatile and easily prepared nanomaterials with both imaging and therapeutic properties have received significant attention in cancer diagnostics and therapeutics. Here, we facilely fabricated Gd 3+ -chelated poly(isobutylene- alt -maleic anhydride) (PMA) framework pendent with perylene-3,4,9,10-tetracarboxylic diimide (PDI) derivatives and poly(ethylene glycol) (PEG) as an efficient theranostic platform for dual-modal photoacoustic imaging (PAI) and magnetic resonance imaging (MRI)-guided photothermal therapy. The obtained polymeric nanoparticles (NPs) chelated with Gd 3+ (PMA–PDI–PEG–Gd NPs) exhibited a high T 1 relaxivity coefficient (13.95 mM –1 s –1 ) even at the higher magnetic fields. After 3.5 h of tail vein injection of PMA–PDI–PEG–Gd NPs, the tumor areas showed conspicuous enhancement in both photoacoustic signal and T 1 -weighted MRI intensity, indicating the efficient accumulation of PMA–PDI–PEG–Gd NPs owing to the enhanced permeation and retention effect. In addition, the excellent tumor ablation therapeutic effect in vivo was demonstrated with living mice. Overall, our work illustrated a straightforward synthetic strategy for engineering multifunctional polymeric nanoparticles for dual-modal imaging to obtain more accurate information for efficient diagnosis and therapy.