One-pot synthesis of albumin-gadolinium stabilized polypyrrole nanotheranostic agent for magnetic resonance imaging guided photothermal therapy

Theranostic agents with perfect properties are needed urgently for the development of imaging guided photothermal therapy (PTT). In this work, Gd-integrated polypyrrole nanotheranostic agent (PPy@BSA-Gd) was successfully built through selecting bovine serum albumin (BSA) as both stabilizers for polymerization and biomimetic mineralization in "one pot". The obtained PPy@BSA-Gd possessed high stability and excellent photothermal property. Besides, relevant cellular assays indicated that PPy@BSA-Gd had fantastic cytocompatibility which could be further internalized by cancer cells. Due to their high longitudinal relaxivity value (r₁ = 10.203 mM^-1s^-1), PPy@BSA-Gd could serve as considerable probe for T1-weighted magnetic resonance imaging (MRI). After tail vein injection of PPy@BSA-Gd, the MR signal of tumor section exhibited a time-dependent increase, indicating effective tumor accumulation of PPy@BSA-Gd. Notably, when exposed to 808 nm laser, the tumor growth of PPy@BSA-Gd treated mice could be inhibited by photothermal ablation successfully. All the results demonstrated the well-designed PPy@BSA-Gd have the potential for tumor diagnose and photothermal therapy.