Bespoke ZnO NPs Synthesis Platform to Optimize Their Performance for Improving the Grain Yield, Zinc Biofortification, and Cd Mitigation in Wheat

Nanomaterials (NMs), particularly ZnO nanoparticles (NPs), show great promise in sustainable agriculture for enhancing crop production, mineral nutrition, and food safety. However, custom synthesis of NMs to optimize performance is still a bottleneck. This study synthesized three types of ZnO (NPs) (nZnO-1, nZnO-2, and nZnO-3) with different particle size, charge, and dissolution properties and were foliar-applied to wheat under field conditions. Foliar application of nZnO-3 significantly increased wheat grain by 15.2% and biological yield by 9.5% compared to that of the unamended control. Both nZnO-2 and nZnO-3 significantly improved the Zn content in whole wheat grain (21.0 and 15.6%, respectively) and starchy endosperm (31.8 and 13.1%, respectively), enhanced the Zn bioavailability (40.9 and 43.3%, respectively), and increased the estimated daily intake (EDI) of Zn (55.1 and 23.8%, respectively). Impressively, nZnO-3 also significantly reduced Cd concentration in whole wheat grain (17.2%) although it did not affect the Cd level in wheat flour. Additionally, all Zn treatments increased the levels of crude protein (5.2-15.7%) and other nutrients (e.g., S, Fe, Mn) in wheat grains. These findings underscore the potential of tailored ZnO NPs in wheat biofortification and point toward a sustainable approach for agricultural production through a controlled synthesis platform..