Urea‑functionalized amorphous calcium phosphate nanofertilizers: optimizing the synthetic strategy towards environmental sustainability and manufacturing costs Carmona Fernández, Francisco Jesús Ramírez Rodríguez, Gloria Belén Delgado López, José Manuel This work has been performed thanks to the funding by Fondazione CARIPLO (Project No. 2016-0648: Romancing the stone: size-controlled HYdroxyaPATItes for sustainable Agriculture – HYPATIA). JMDL acknowledges Spanish Ministry of Science, Innovation and Universities of Spain (MCIU/AEI/FEDER, UE) for funding through the projects NanoVIT (RTI-2018-095794-A-C22) and NanoSmart (RYC-2016-21042). GBRR also acknowledges the Spanish MICIU for her postdoctoral contract within the Juan de la Cierva Program (JdC-2017). Financial support for this work was also provided by the Marie Skłodowska-Curie Standard Fellowships (888972-PSust- MOF, F.J.C.) within the European Union research and innovation framework programme (2014-2020). We thank Prof. Jan Skov Pedersen (Aarhus University, DK) for technical and scientific assistance on SAXS experiments. Nanosized fertilizers are the new frontier of nanotechnology towards a sustainable agriculture. Here, an efficient N-nanofertilizer is obtained by post-synthetic modification (PSM) of nitrate-doped amorphous calcium phosphate (ACP) nanoparticles (NPs) with urea. The unwasteful PSM protocol leads to N-payloads as large as 8.1 w/w%, is well replicated by using inexpensive technical-grade reagents for cost-effective up-scaling and moderately favours urea release slowdown. Using the PSM approach, the N amount is ca. 3 times larger than that obtained in an equivalent one-pot synthesis where urea and nitrate are jointly added during the NPs preparation. In vivo tests on cucumber plants in hydroponic conditions show that N-doped ACP NPs, with half absolute N-content than in conventional urea treatment, promote the formation of an equivalent amount of root and shoot biomass, without nitrogen depletion. The high nitrogen use efficiency (up to 69%) and a cost-effective preparation method support the sustainable real usage of N-doped ACP as a nanofertilizer. 2021-04-23T07:34:13Z 2021-04-23T07:34:13Z 2021-02-09 info:eu-repo/semantics/article Carmona, F.J., Dal Sasso, G., Ramírez-Rodríguez, G.B. et al. Urea-functionalized amorphous calcium phosphate nanofertilizers: optimizing the synthetic strategy towards environmental sustainability and manufacturing costs. Sci Rep 11, 3419 (2021). [https://doi.org/10.1038/s41598-021-83048-9] http://hdl.handle.net/10481/68064 10.1038/s41598-021-83048-9 eng info:eu-repo/grantAgreement/EC/H2020/888972 http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España Springer Nature