As both the nitrodopamine-based and polyphosphonate ligands are not soluble in toluene, we first disperse the nanoparticles in water before ligand exchange. A portion of the nanoparticle solution with the amount needed for the ligand exchange (typically, 20 mg) was dried from toluene on the Schlenk line. The solid residue was dissolved in 1 mL of ethanol, followed by 15 min of sonication. Then, the nanoparticles were dried again and dissolved in 1 mL of methanol in the same way as described above. Finally, dried nanoparticles were dissolved in the amount of MQ water required for the ligand exchange. For the NPs stabilized with MEEAA, slight turbidity was observed in the final dispersion caused by the partial desorption of carboxylic acid.