Zinc delivery system constructed from food-borne nanoparticles derived from Undaria pinnatifida

Food-borne nanoparticles from Undaria pinnatifida (UPFNs) were prepared and successfully applied as nanocarriers for microelement zinc delivery. UPFNs were spherical nanoparticles with average sizes of about 4.07 ± 1.09 nm, which chelated with zinc ions through amino nitrogen and carboxyl oxygen atoms as characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ¹H nuclear magnetic resonance spectroscopy. Thermodynamic analysis revealed that the overall chelation process between UPFNs and zinc ions was a spontaneous enthalpy-driven endothermic reaction. Compared to zinc sulfate, UPFN-Zn²⁺ showed higher solubility both in phytic acid solution and the process of gastrointestinal digestion. Meanwhile, no obvious cytotoxicity was found in UPFNs and UPFN-Zn²⁺. Specifically, UPFN-Zn²⁺ could successfully rescue cell viability, DNA replication activity and restore cell proliferation ability in zinc-deficient cells induced by a specific zinc chelator TPEN. Overall, UPFNs might serve as efficient, stable, and safe nanocarriers for zinc delivery.