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Modified magnetic starch nanoparticles (FA-StNP@Fe2O3) were synthesized by conjugating folic acid (FA-PEG-NH2) onto the surface of magnetic starch nanoparticles (StNP@Fe2O3) prepared by reverse microemulsion method. The synthesized FA-StNP@Fe2O3 was investigated by transmission electron microscopy and zeta potential analysis. The average size of its well dispersed particles was 250 nm. The iron concentration of 2 mg/g was detected by phenanthroline method. Placing FA-StNP@Fe2O3 nanoparticles in the alternating magnetic field for 30 min resulted in an increase in the suspension temperature from ambient temperature (37°) to a value between 42° and 43°. Co-cultured nanoparticles and Hela cell line or normal HUEC-12 cell line, and the biological effects at the cellular level were investigated in the alternating magnetic field using MTT assay, Hochest-PI double staining and flow cytometry analysis. Experimental results showed that FA-StNP@Fe2O3 within acertain concentration range has no obvious effect on cell proliferation. When treated in the magnetic field, apoptosis rate on Hela induced by FA-StNP@Fe2O3 was 13.4%. Prussian blue staining analysis confirmed that the nanoparticles modified with folic acid had improved ability in tumor cell-targeting, and therefore, potential applications in biomedical and magnetocaloric areas. It is expected be applied in tumor targeting therapy in the near future. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has filled a gap in our knowledge regarding the prevention of CoVs. Swine coronavirus (CoV) is a significant pathogen that causes huge economic losses to the global swine industry. Until now, anti-CoV prevention and control have been challenging due to the rapidly generated variants. Silver nanoparticles (AgNPs) with excellent antimicrobial activity have attracted great interest for biosafety prevention and control applications. In this study, we synthesized chitosan-modified AgNPs (Chi-AgNPs) with good biocompatibility to investigate their antiviral effects on swine CoVs. In vitro assays showed that Chi-AgNPs could significantly impaired viral entry. The direct interaction between Chi-AgNPs and CoVs can destroy the viral surface spike (S) protein secondary structure associated with viral membrane fusion, which is caused by the cleavage of disulfide bonds in the S protein. Moreover, the mechanism showed that Chi-AgNPs reduced the virus-induced apoptosis of Vero cells via the ROS/p53 signaling activation pathway. Our data suggest that Chi-AgNPs can serve as a preventive strategy for CoVs infection and provide a molecular basis for the viricidal effect of Chi-AgNPs on CoVs.

Cisplatin (DDP) is a potent chemotherapeutic drug, which can regulate tumor cell apoptosis by up-regulating caspase-3 activity. Thus, monitoring caspase-3 activity in breast cancer cells can directly illustrate the efficiency of DDP treatment. In this study, by using reduced graphene oxide (rGO) as a quencher of a fluorescence labeled peptide, we developed an "off to on" method to monitor the effect of DDP on caspase-3 in breast cancer cells. In this method, the rGO quenched fluorescence with an ultra-high level of efficiency. Caspase-3 hydrolyzed the polypeptide probe, generating two segments of different lengths. The release of a short segment marked with fluorophores led to the recovery of the fluorescence signal (Ex/Em = 450/521 nm). Under the optimal conditions, the linear range of caspase-3 was 0.4-7 U mL -1 and the limit of detection was 0.33 U mL -1 . The upregulating effect of DDP on intracellular caspase-3 activity was visualized with the "off to on" method and flow cytometry assay showed that caspase-3 activity increased along with the apoptosis rate of tumor cells. The above results show the practical application of the method for evaluating the efficacy of drugs against cancer cells.

Ether-based electrolytes are promising for secondary batteries due to their good compatibility with alkali metal anodes and high ionic conductivity. However, they suffer from poor oxidative stability and high toxicity, leading to severe electrolyte decomposition at high voltage and biosafety/environmental concerns when electrolyte leakage occurs. Here, we report a green ether solvent through a rational design of carbon-chain regulation to elicit steric hindrance, such a structure significantly reducing the solvent's biotoxicity and tuning the solvation structure of electrolytes. Notably, our solvent design is versatile, and an anion-dominated solvation structure is favored, facilitating a stable interphase formation on both the anode and cathode in potassium-ion batteries. Remarkably, the green ether-based electrolyte demonstrates excellent compatibility with K metal and graphite anode and a 4.2 V high-voltage cathode (200 cycles with average Coulombic efficiency of 99.64 %). This work points to a promising path toward the molecular design of green ether-based electrolytes for practical high-voltage potassium-ion batteries and other rechargeable batteries., (© 2023 Wiley-VCH GmbH.)

Based on the strong interaction between histidine and copper ions and the signal enhancement effect of gold-labeling carbon nanotubes, an electrochemical sensor is established and used to measure copper ions in river water. In this study the results show that the concentrations of copper ion have well linear relationship with the peak current in the range of 10 -11 -10 -7  mol/L, and the limit of detection is 10 -12  mol/L. When using this method to detect copper ions in the Xiangjiang River, the test results are consistent with the atomic absorption method. This study shows that the sensor is convenient to be used in daily monitoring of copper ions in river water.