Post-Complexation Synthesis of Responsive Polymer Nanoparticles Functionalized with Kinetically Inert Europium(III) Complexes for Bicarbonate Sensing

Abstract Engineering nanomaterials to perform a specific function requires control of the complex chemistry involved in the formation of the nanomaterial and thus control of the resulting architecture. Here, we explored the sequence of steps required to make responsive nanoparticles (NPs), nanooptodes, for bicarbonate sensing. The sensor action is based on lanthanide-centered interactions and lanthanide luminescence, which, in addition to providing the sensing action, informs on the NP architecture. Two NP-forming reactions were tested, but only the synthesis pathway where amphiphilic components were used reproducibly provided functional nanooptodes with a responsive lanthanide complex placed at the nanoparticle–solution interface. This protocol creates nanooptodes with a shelf life of years and an explainable response to bicarbonate. The lanthanide luminescence provides real-time feedback on the NP structure, ensuring reliability and reproducibility across sensing applications.