Porous ceria nanorods modified with Fe or Co were prepared via a hydrothermal method. The structural properties, catalytic activities for the total oxidation of propane, and catalytic mechanisms of these materials were systematically investigated by X-ray diffraction, Raman spectroscopy, N 2 adsorption–desorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, catalytic activity measurements and in situ Fourier transform infrared spectroscopy. Co-modified ceria exhibited the best catalytic activity during propane oxidation as well as enhanced reducibility due to the synergistic interactions between the Co and the CeO 2 support. Variations in the activating ability and reducibility of the catalysts resulted in the formation of distinctive intermediates during the catalytic process, and this explained the observed differences in catalytic performance.
Recently, catalytic therapy on the basis of Fenton reaction represents a very promising paradigm for potential cancer therapy, which has inspired great research interest and got fast progress. Nevertheless, it remains challenging to fabricate nanocatalytic systems that can precisely perform catalytic activity in tumor tissues without causing toxicity to adjacent normal tissues. Herein, we designed and fabricated a porous CeO 2 nanorods that can selectively perform therapeutic activity in the weakly acidic tumor microenvironment via converting H 2 O 2 into •OH to kill cancer cells, meanwhile, the normal tissues are protected by decomposing H 2 O 2 into O 2 in the physiological environment. Specifically, benefiting from the porous structure, such CeO 2 nanorods could be loaded with Indocyanine green (ICG) that could both contribute itself to generate singlet oxygen ( 1 O 2 ) and convert near-infrared (NIR) light to hyperthermia. Once exposed to NIR light, on the one hand, the catalytic activity of CeO 2 was significantly enhanced by photothermal effect of ICG for highly efficient tumor catalytic therapy; on the other hand, the generated hyperthermia and 1 O 2 by ICG can further synergistically enhance the therapy efficiency via directing killing cancer cells. The current study provides a proof-of-concept demonstration of tumor-specific therapy with minimal non-targeted toxicity.
Objective The aim was to produce the first report of assembling degradable stimuli-responsive dithio-polydopamine coating with a cancer target unit for synergistic and targeted drug delivery.Methods A multifunctional drug delivery system was constructed by coating a dual-responsive dithio-polydopamine (PDS) on porous CeO2 nanorods and subsequent conjugation of lactose derivative, where the PDS was formed by self-polymerization of dithio-dopamine (DOPASS).Results The multifunctional drug delivery system displayed excellent cancer targeted ability resulting from the conjugation of lactose derivative, which could specifically recognize the overexpressed asialoglycoprotein receptors on the surface of HepG2 cells. It also showed a dual-responsive property of glutathione and pH, achieving controllable drug release from the cleavage of disulfide bond and subsequent degradation of PDS in cancer cells. Moreover, the degradation of PDS led to the exposure of CeO2 nanorods, which has a synergistic anticancer effect due to its cytotoxicity to cancer cells.Conclusion This work presents a good example of a rational design towards synergistic and targeted DDS for cancer chemotherapies.
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