Study Of Zinc Nanocarriers Derived From Beef Broth

As an essential micronutrient,zinc plays a vital role in certain key biological processes in human growth,and is widely used as a nutritional supplement.However,inorganic metal salts are not good micronutrient supplements due to the negative effects.As an alternative method,certain chelating peptides with binding groups have been used as carriers to enhance zinc absorption in the gastrointestinal tract.But the preparation and separation of the peptides is time consuming and costly.Recently,a new type of nanoparticles,namely food-borne nanoparticles?FNs?,were discovered in human daily foods.These FNs have a mass of functional groups that can be used as nanocarriers to chelate metal ions in micronutrient supplements.In this paper,a type of hydrophilic FNs were prepared from the beef broth at different cooking time?30,50 and 70 min?using nutritious beef as raw materials,and their potential application as nanocarriers for zinc was investigated.The broth FNs were quasi-spherical with good water-solubility,ultrasmall size?less than 11 nm?and the size of the FNs decreased gradually with the extension of cooking time.The FNs have good fluorescent property which can emit strong blue fluorescence under 365 nm UV irradiation.X-ray photoelectron spectroscopy?XPS?and fourier transform infrared?FT-IR?spectroscopy analysis showed the presence of abundant hydroxyl,amino,and carboxyl groups on the surface of nanoparticles,which were useful for Zn?II?chelation.FT-IR bands corresponding to the vibration of C=O at 1,688 cm^-1 in the spectrum of the FNs shifted to 1,718 cm^-1 after binding with Zn?II?ions,suggesting the participation of the carbonyl?C=O?group in the binding between the FNs and Zn?II?ions.In the XPS spectrum of Zn?II?-FNs,the appearance of Zn2p peaks,at 1,021.6 and1045 eV for Zn?II?-FNs clearly demonstrated the formation of Zn-O between the FNs and zinc ions.Moreover,a downfield shift was found for the signals of Zn?II?-FNs in¹H-NMR spectroscopy,which strongly suggested the binding of Zn?II?ions to FNs through carboxylic acid,hydroxyl and amine group for Zn?II?chelation.In addition,the bio-distribution of FNs and Zn?II?-FNs complex in normal rat kidney cells?NRK cells?demonstrated that they could easily enter NRK cells and they were mainly distributed in the cytoplasm.More important,no obvious cytotoxicity was found for the Zn?II?-FNs.The results revealed that the FNs from beef broth may have a potential as nanocarriers for zinc chelation...