Facile Synthesis Of Biocompatible Fe3o4-Based Nanoparticles For Ph-Responsive Dual-Model Magnetic Resonance Imaging- Guided Tumour Eradication By Photothermal Therapy

The early accurate diagnosis is key to the successful treatment of tumours. However, single magnetic resonance imaging ( MRI ) mode cannot satisfy the high requirement of accurate diagnosis owing to their inherent defects. Herein, we constructed poly ( acrylic ) acid ( PAA ) -modified Fe3O4 @ MnO2 nanoparticles ( Fe3O4 @ MnO2 @ PAA NPs) as a kind of pH-responsive T-1/T-2 dual-model MRI guiding photothermal therapy ( PTT). Fe3O4 core enabled Fe3O4 @ MnO2 @ PAA NPs to weaken T-2 signal in clinical MRI examination, and MnO2 nanoshells were able to decompose into paramagnetic manganous ions under the weakly acidic environment of tumours , achieving pH-responsive T-1-weighted MRI. Such pH-responsive T-1/T-2 dual-model CAs with sensitivity and specificity provided more comprehensive information for diagnosis of tumours. Moreover, Fe3O4 @ MnO2 @ PAA NPs exhibited excellent absorption in near-infrared ( NIR) region , making them as good NIR photothermal agents for PTT. This work presented novel pH-responsive theranostic agents integrated dual-model imaging and PTT functionalities , and demonstrated their potential for stimuli-responsive MRI guided PTT of cancer.