Platinum-Doped Prussian Blue Nanozymes for Multiwavelength Bioimaging Guided Photothermal Therapy of Tumor and Anti-Inflammation

Abstract

Developing appropriate photothermal agents to meet complex clinical demands is an urgent challenge for photothermal therapy of tumors. Here, platinum-doped Prussian blue (PtPB) nanozymes with tunable spectral absorption, high photothermal conversion efficiency, and good antioxidative catalytic activity are developed by one-step reduction. By controlling the doping ratio, PtPB nanozymes exhibit tunable localized surface plasmon resonance (LSPR) frequency with significantly enhanced photothermal conversion efficiency and allow multiwavelength photoacoustic/infrared thermal imaging guided photothermal therapy. Experimental band gap and density functional theory calculations further reveal that the decrement of free carrier concentrations and increase in circuit paths of electron transitions co-contribute to the enhanced photothermal conversion efficiency of PtPB with tunable LSPR frequency. Benefiting from antioxidative catalytic activity, PtPB can simultaneously relieve inflammation caused by hyperthermia. Moreover, PtPB nanozymes exhibited good biosafety after intravenous injection. Our findings provide a paradigm for designing safe and efficient photothermal agents to treat complex tumor diseases.

Prussian Blue: A Nanozyme with Versatile Catalytic Properties

“…The incorporation of a chemical element can modify the pH dependence of the CATlike activity of PB. In this way, PB nanocubes doped with platinum prepared by in situ reduction of PtCl 6 2− on the surface of PB showed prominent CAT-like activity at pH 6.5: the dissolved O 2 concentration rose from 4.41 mg/L for PB alone to 38.25 mg/L for a PB with a high content in Pt [ 43 ].…”

Nanozymes Regulate Redox Homeostasis in ROS-Related Inflammation

“…Therefore, it is believed that the antioxidant activity of nanozymes will be helpful in the treatment of inflammation. For instance, as reported by ( Li et al, 2016 ) platinum-doped Prussian blue nanoparticles (PPBs) with ROS-scavenging properties relieved inflammation induced by tumor photothermal therapy (PTT) ( Li et al, 2021a ).…”

“…Cardiac ischemia-reperfusion (CIR) injury is one of the most complicated diseases and its underlying mechanisms are not clear. With its characteristic feature of excess ROS in the mitochondria in mind, Zhang et al developed a hybrid nanozyme consisting of a protein scaffold and a metal nanoparticle core that harbored both mitochondria-targeting and ROS-removal properties ( Li et al, 2021a ). The de novo design strategy in artificial enzyme synthesis shed light on the development of nanozyme and ameliorated oxidative injury in CIR.…”

Nanozymes in Tumor Theranostics

“…The platinum-doped Prussian blue (PtPB) nanozyme was developed to improve the photothermal property in a large wavelength range during the process of PTT ( 89 ). On the other hand, the PtPB nanozyme is endowed with superior CAT and SOD-like catalytic activities by Pt doped with PB nanotubes, which contributed to the relieved inflammation caused by PTT, along with significant tumor inhibition ( 89 ).…”