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• F-PCP NPs for rheumatoid arthritis are developed. • F-PCP NPs has obtained excellent photothermal therapy performance. • F-PCP NPs actively target M1 macrophages to reduce its proliferation. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint hypoxia and the proliferation of M1 macrophages. Therefore, relieving hypoxia and removing M1 macrophages will be a new direction in the treatment of RA. Folic acid (FA)-loaded PCP nanoparticles Fe-Co prussian blue analogue@CeO 2 @PDA (F-PCP) were used for in situ oxygen (O 2) production/chemodynamic/photothermal/treatment of RA. On one hand, PDA-mediated photothermal therapy also has a certain effect on the removal of proliferative M1 macrophages. On the other hand, under the irradiation of NIR laser, F-PCP has obtained excellent photothermal therapy (PTT) performance, which accelerates the Fenton/Fenton-like reaction to produce reactive oxygen species and O 2 , so as to achieve the chemodynamic therapy (CDT) that inhibits the proliferation of M1 macrophages. It is worth noting that the RA was improved by the synergistic action of CDT and PTT, and the generation of oxygen can alleviate RA hypoxia, which is a means to improve CDT. Therefore, the F-PCP NPs show great potential in improving the therapeutic effect of RA. [ABSTRACT FROM AUTHOR]

• The ACPP nanoeggs relieve hypoxic tumor microenvironment and elevate the generation of singlet oxygen (1O 2) in SDT. • The ACPP nanoeggs convert H 2 O 2 into hydroxyl radicals (•OH) for chemodynamic therapy (CDT). • The decoration of Pd increased the content ratio of Ce3+/Ce4+, significantly enhanced enzymatic activities of nanoeggs. There is an increasing appreciation for sonodynamic therapy (SDT) that is triggered by ultrasound (US) to treat deep-seated tumors noninvasively. Whereas, the low production of reactive oxygen species (ROS) limits its effect because of the rapid recombination of electron-hole (e–-h+) pairs in sonosensitizers. Herein, Au@CeO 2 -Pd-PFH (ACPP) nanoegg with significantly improved sonosensitization and Fenton-like catalyst was manufactured. Under the irradiation of US, the ACPP nanoegg exhibited improved efficiency of ROS production owing to the narrow bandgap of 1.72 eV and the efficient e–-h+ separation ability. Additionally, the designed ACPP nanoegg mimicked not only peroxidase activity to convert endogenous hydrogen peroxide (H 2 O 2) into hydroxyl radicals (•OH) for chemodynamic therapy (CDT) but also catalase activity to produce oxygen (O 2) for ameliorating hypoxia and enhancing SDT. The decoration of Pd increased the content ratio of Ce3+/Ce4+, significantly elevating the enzymatic activity of nanoegg. With further loading of perfluorohexane (PFH), which led to a transition under US irradiation, US imaging of the tumor was realized. Through both in vitro and in vivo experimental studies, the nanoegg developed in this work was demonstrated to be a promising strategy for cancer nanotheranostic. [ABSTRACT FROM AUTHOR]

• Engineered exosomes can scavenge a variety of toxic reactive oxygen species using the activity of multiple nanozymes. • Engineered exosomes can target the brain in two ways: actively with targeted peptides and passively with photothermal action. • Engineered exosomes reduce microglia activation and mitochondrial damage. Alzheimer's disease (AD) is one of the leading causes of dementia. The pathogenesis of AD is complex, and oxidative stress, which is involved in neuronal damage through various pathways, is considered to be a central part of AD pathogenesis. Therefore, we took advantage of the blood–brain barrier permeability of biogenic extracellular vesicles to load the high-performance antioxidant resveratrol (Res) and platinum (Pt) nanoparticles with multiple enzymatic activities into the extracellular vesicles and then deliver the 'Trojan horses' to the central nervous system to exert synergistic antioxidant effects. In this study, Res-Pt@EVs-RVG was designed to preferentially target the brain using rabies virus glycoprotein (RVG) peptides. In addition, the large photothermal effect of Pt nanoparticles increased the drug penetration and its high blood–brain barrier penetration ability was confirmed in vivo animal experiments. We found through multiple experiments that Res-Pt@EVs-RVG was well absorbed by cells, reduced intracellular reactive oxygen levels, improved mitochondrial damage, and attenuated glial cell activation while reducing neuronal loss in the brains of AD mice and improving memory impairment in APP/PS1 mice. Our results suggest that a biogenic extracellular vesicles-based drug delivery strategy overcomes the disadvantage of poor drug penetration into the central nervous system (CNS) and provides a potential platform for the effective treatment of AD. [ABSTRACT FROM AUTHOR]

Increasing the formation of reactive oxygen species (ROS) and reducing the elimination of ROS are the two main objectives in the development of novel inorganic sonosensitizers for use in sonodynamic therapy (SDT). Therefore, BTO–Pd–MnO 2 –HA nanocomplexes with targeted tumor cells and degradable oxygen-producing shells were designed as piezoelectric sonosensitizers for enhancing SDT. The deposition of palladium particles (Pd NPs) leads to the formation of Schottky junctions, promoting the separation of electron–hole pairs and thereby increasing the efficiency of toxic ROS generation in SDT. The tumor microenvironment (TME) triggers the degradation of MnO 2 , and the released Mn2+ ions catalyze the generation of hydroxyl radicals (•OH) from H 2 O 2 through a Fenton-like reaction. BTO–Pd–MnO 2 –HA can continuously consume glutathione (GSH) and generate O 2 , thereby improving the efficiency of SDT and chemodynamic therapy (CDT). A multistep enhanced SDT process mediated by the piezoelectric sonosensitizers BTO–Pd–MnO 2 –HA was designed, targeted by hyaluronic acid (HA), activated by decomposition in TME, and amplified by deposition of Pd. This procedure not only presents a new alternative for the improvement of sonosensitizers but also widens the application of piezoelectric nanomaterials in biomedicine. [ABSTRACT FROM AUTHOR]