Biocompatible Polymer Nanocomposites Integrating Magnetic Polyoxomolybdates for Enhanced MRI and On-Site Activated Photothermal Properties.

This work reports the ionic composition of a PEGylated and chemically crosslinked polyethyleneimine with a gadolinium-coordinated polyoxomolybdate cluster, K17 [Gd(P2 Mo17 O61 )2 ], via electrostatic interaction. The prepared composites form nanoobjects with an average size of ≈27 nm at dried state and maintain structural stability in aqueous solution. While the biocompatibility on HeLa cells is demonstrated, the polymer-shielded multifunctional nanoplatform shows both the combined magnetic resonance imaging and redox-triggered photothermal conversion effect. As a contrast agent, the T1 -weighed relaxivity reaches up to 22.77 mm-1  s-1 . The photothermal conversion of the prepared composites can be aroused by yielding a broad near infrared (NIR) adsorption through on-site reduction of the glutathione that is enriched in the tumor environment. The high efficiency ≈61.0% under the irradiation of 808 nm NIR laser illustrates a distinct treatment capability according to cell counting Kit-8 assay while the obvious inhibition for the growth of tumor cells is observed.