Quercetin@UiO-66 NPs and chloroquine in combined tumor therapy by dual autophagy-ubiquitination system blockade.

In this study, we propose a novel therapy system composed of UiO-66 nanoparticles, which contain quercetin combined with chloroquine (UQCNP), to achieve dual autophagy-ubiquitination blockade. Through UiO-66 NP drug loading, the solubility of quercetin (a proteasome inhibitor) was improved under physiological conditions, thereby increasing its effective concentration at the tumor site. The cell experiment results showed that UQCNP significantly increased the apoptosis rate of 4T1 cells by 73.6%, which was significantly higher than other groups. Transmission electron microscopy results showed that the autophagosome of cells in the UQCNP treatment group was significantly lower than that in other treatment groups. Moreover, western blot results showed that, compared with other groups, LC3 expression and proteasome activity (p < 0.01), as well as the tumor volume of mice treated with UQCNP (p < 0.01) were significantly reduced. These results indicate that UQCNP achieves effective tumor therapy by blocking the autophagy and proteasome pathways synchronously.

ZnO@Polyvinyl Alcohol/Poly(lactic acid) Nanocomposite Films for the Extended Shelf Life of Pork by Efficient Antibacterial Adhesion.

The proliferation of microorganisms is an important reason for meat spoilage and deterioration. Freezing and packaging by polymer films and preservatives are commonly used to preserve meat. While the energy consumption of freezing is very big, the polymer films made by petroleum bring up heavy environmental pressure. In the present study, biodegradable antibacterial ZnO@PLA (ZP) and ZnO@PVA/PLA (ZPP) nanocomposite films used as food packaging have been synthesized by the solvent evaporation method and coating method, respectively. Compared with films without ZnO NPs, ZP and ZPP both had long-term bacteriostasis for 24 and 120 h at temperatures of 25 and 4 °C, respectively. Moreover, the antibacterial effect showed positive relevance with the increase of the ZnO NP concentration. In addition, the antibacterial effect of ZPP was better than that of ZP in the same condition. Scanning electron microscopy showed that the numbers of methicillin-resistant staphylococcus aureus (MRSA) on ZP and ZPP were significantly reduced compared to that in the blank film, and ZPP caused the morphology of MRSA to change, which means that the antibacterial mechanism of ZP and ZPP composite films might be related to antibacterial adhesion. In conclusion, ZPP films have great potential to be regarded as the candidate of food packing to extend the shelf life of pork.

Solubility of ZnO Nanoparticles in Food Media: An Analysis Using a Novel Semiclosed Dynamic System.

Food media can affect the solubility of zinc oxide nanoparticles (ZnO NPs). Moreover, when a single digestive fluid and a three-step digestion system were applied to investigate the fate of ZnO NPs, several contradictory results were obtained. Here, we manipulated a novel semiclosed in vitro dynamic digestion system to investigate the difference in the released ionic zinc (Zn2+) content in three types of artificial fluids in the presence of different food media. The results show that there was a significant difference in the released Zn2+ content between the three different types of digestion systems in the presence of the same food media. In addition, the released Zn2+ content was significantly different when different types of food media were applied to the same digestion system. These results demonstrate that the different levels of released Zn2+ content can be ascribed to the difference in digestion systems and food media.