Developing biodegradable photothermal agent holds great significance for potential clinical translation of photothermal therapy. In the current study, one-pot hydrothermal synthesis of MoS nanoflakes with desirable degradation capability was presented. The participation of poly(acrylic acid) (PAA) in hydrothermal process could not only facilitate the modification of polyethylene glycol (PEG), but also bestow degradability to the prepared MoS nanoflakes. Moreover, the PEGylated hybrid nanoflakes (MoS-PPEG) also exhibited excellent stability in various medium and outstanding photothermal properties. Interestingly, MoS-PPEG behaved distinctly different degradation rate in diverse condition. The rapid degradation of MoS-PPEG was observed in neutral pH solution, whereas much slower degradation occurred in an acidic tumor microenvironment. Furthermore, data indicated that the major degradation product of MoS-PPEG was water-soluble Mo-based ion. Meanwhile, the good in vitro biocompatibility of MoS-PPEG was also confirmed in terms of cytotoxicity and hemolysis. With favorable photothermal performance, MoS-PPEG can efficiently killing cancer cells in vitro and suppress the tumor growth in vivo. More importantly, the gradual decreasing content of MoS-PPEG in organs and detectable Mo element in urine of mice suggested that the degradability of MoS-PPEG might facilitate its excretion to some degree. Hence, the degradable MoS nanoflakes prepared by one-pot hydrothermal routine may provide insight for further biomedical applications of inorganic photothermal agent.

No abstract

NiFe layered double hydroxides (LDHs) usually exhibit high waterdissociation ability in the alkaline media and also provide an ideal substrate for anchoring noble metals, such as platinum (Pt), due to the 2D microstructure. Appropriate regulation of the interaction between Pt and substrate could enhance the intrinsic activity of composite catalysts toward the hydrogen evolution reaction (HER) in the alkaline media. Herein, we electrodeposit Pt nanoparticles on amorphous NiFe LDH (Pt/NiFe-ED) or crystalline NiFe LDH (Pt/NiFe-HD) to regulate the interaction between Pt and NiFe LDH. Experimental results reveal that Pt nanoparticles on NiFe-ED are smaller than those on NiFe-HD and possess a narrower size distribution. Thus, Pt/NiFe-ED (300 μM) exhibits a much lower overpotential of 81 mV at 100 mA cm −2 than Pt/NiFe-HD. In contrast, Pt/NiFe-HD exhibits a higher intrinsic activity than Pt/NiFe-ED, which could be caused by the easily elongated Pt−O bond. These findings provide new opportunities to understand the relationship between activity and crystallinity of substrates in the composite electrocatalyst.