2.2. Synthesis of Phosphonate Modified DSNPs (PDSNPs)

Pristine DSNPs (100 mg) were dispersed in 13 mL of Milli-Q water using a bath sonicator for 3 min. Phosphonate silane 3-(trihydroxysilyl)propyl methylphosphonate (THMP) (0.13 mL) was added in another 13 mL of Milli-Q water and the pH was adjusted to 5.0–6.0. This solution was added to the particle dispersion and the mixture was stirred at 100 °C and 600 RPM under reflux overnight. Afterwards, particles were separated through centrifugation at 24,700× g for 10 min and washed twice with excess of ethanol and once with water. The PDSNPs were dried in oven at 80 °C and stored at room temperature for further use.