Biao Yuan,Bing Jiang,Han Li,Xiao Xu,Fei Li,David Julian McClements,Chongjiang Cao
Titanium dioxide (TiO 2 ) particles are widely employed in foods and supplements as lightening agents. A substantial fraction of the particles in commercial TiO 2 ingredients fall within the nanoscale, i.e., they have diameters below 100 nm. A biocorona can form around TiO 2 particles when they are incorporated into food matrices containing plant proteins . In this study, we investigated the molecular interactions between two hydrophobic plant proteins (gliadin and zein) and four types of surface-modified TiO 2 nanoparticles (TCN, TCN-1, TCN-2 and TCN-3). Ultraviolet–visible absorption, fluorescence quenching, and Fourier transform infrared spectroscopy indicated that the plant proteins interacted with the surfaces of the TiO 2 nanoparticles, resulting in changes in their molecular conformations . Quartz crystal microbalance analysis indicated that the mass of the hard corona increased as the number of hydroxyl groups on the surfaces of the TiO 2 nanoparticles increased, which implied that hydrogen bonding played an important role in the formation of the biocorona. These results provide a better understanding of the interactions that may occur in food matrices containing both plant proteins and TiO 2 nanoparticles.
Lingxiangyu Li,Ashfeen Ubaid Khan,Xiang Zhang,Xiaoting Qian,Yawei Wang
With the rapid development of nanotechnology, personal care products with silver nanoparticles (Ag-NPs) or zinc oxide nanoparticles (ZnO-NPs) are being widely used because of their superior antibacterial efficacies. Biological fluids would thus inevitably interact with Ag-NPs or ZnO-NPs. Human tear fluid is an important model that was ignored in past studies, restricting the comprehensive understanding of the stability and health risks of Ag-NPs and ZnO-NPs. Herein, two simulated tear fluid models were examined, allowing us to understand potential transformations that can affect the properties and toxicity of Ag-NPs and ZnO-NPs. Both Ag-NPs and ZnO-NPs exhibited high chemical stability in the simulated tear fluid containing proteins even after an incubation time of 168 h due to the formation of biocoronae on the particles, resulting in inferior antibacterial activities of Ag-NPs and ZnO-NPs to E. coli. Nevertheless, Ag-NPs and ZnO-NPs could gradually transform into AgCl and Zn5(CO3)2(OH)6 respectively in the simulated tear fluid without protein, wherein AgCl or Zn5(CO3)2(OH)6 accounted for 59.7% of silver or 91.7% of zinc through a selective dissolution method established in this study. The size of AgCl particles was far smaller than that of pristine Ag-NPs, whereas Zn5(CO3)2(OH)6 exhibited a needle-crossed morphology with a large size compared to pristine ZnO-NPs. An enhanced antibacterial efficacy was observed for the transformed Ag-NPs relative to that for pristine Ag-NPs, since high concentrations of dissolved silver were detected in the culture medium with the transformed Ag-NPs. Compared to pristine ZnO-NPs, in contrast, the transformed ZnO-NPs showed moderate antibacterial activity to E. coli. In total, the chemical stability of Ag-NPs and ZnO-NPs in the simulated tear fluid was highly affected by the protein, which would further influence their antibacterial efficacies.
Titanium dioxide (TiO 2 ) is commonly used as food whitening in candies, chocolates, and cakes with high carbohydrate contents. The potential interaction between the food carbohydrate and food grade TiO 2 nanoparticle was little known. Therefore, we explored the interaction between TiO 2 nanoparticles and seven common carbohydrates, including monosaccharides, disaccharides, and polysaccharides. The result showed that all the carbohydrates tested interacted with the surfaces of the TiO 2 nanoparticles and formed biocoronas. TEM and SEM images provided information about the morphology formation of biocoronas. The surface potential and size of the TiO 2 nanoparticles altered after interacting with the carbohydrates. FTIR spectroscopy and QCM-D findings showed insights into the molecular origin and nature interaction between TiO 2 and carbohydrates. The results illustrated that TiO 2 nanoparticles can interact with carbohydrates, enter the body as a food additive, and interact with food matrix for a series of reactions. Compared with monosaccharides or disaccharides, food polysaccharides have stronger adsorption on the surface of nanoparticles. This is a preliminary judgment for the subsequent in vitro simulated digestion. Our result could be useful for understanding and controlling the behavior of nanoparticles in food and the human gut.
危险品化学品经营许可证（带存储）