The development of nontoxic and biocompatible contrast agents (CAs) create new opportunities for potential applications in clinical magnetic resonance imaging (MRI) diagnosis. Manganese-based nanoparticles (NPs) are an emerging new class of MRI CAs that provide impressive contrast abilities with its low immunotoxicity property. Herein, PEGylated Mn2+-chelated Alginate-polydopamine materials (NPs) (PEG-AlgPDA(Ca/Mn) were successfully developed with strong brighter MRI signals with r1=12.54 mM−1 s −1 in 7.0 T MRI images, based on the use of Mn2+ ions as CAs and alginate-polydopamine as a biogenic polymer. The lower pH (5-6) tumor environment promote Mn2+- release from alginate- polydopamine complex to enhance tumor T1 – relaxivity effect. The obtained AlgPDA(Ca/Mn) NPs exhibited significant MRI signal improvement both in in-vitro and in- vivo imaging. Moreover, the excellent AlgPDA(Ca/Mn) NPs biocompatibility was confirmed by a standard MTT assay and Haemotoxylin and Eosin (H&E) staining. Therefore, the developed AlgPDA(Ca/Mn) NPs could provide a new insight for bioresponsive noninvasive tumor detection and comprehensive anatomical diagnosis of cancer cells.
KEYWORDS: Nanostructured materials, Magnetic Resonance Imaging, Polydopamine, Manganese