2.1.2. Functionalization of SiNP with Amino (NH2) Groups

In order to attach functional amino groups to the surface of the SiNP, a slightly modified version of the protocol from Avella et al. [24] was followed. In the beginning of this procedure, 200 mg 3-aminopropyltrethoxysilane (APTES) was dissolved in 20 mL of water and kept at room temperature for 2 h under continuous magnetic stirring to start the hydrolysis reaction. SiNPs (1 g) dissolved in 25 mL ethanol and sonicated for around 30 min was added to the reaction mix and kept at 70 ◦C for 23 h under continuous magnetic stirring. The functionalized SiNPs were then dried at 80 ◦C for 24 h and stored at room temperature. To confirm if the APTES functionalization worked, the samples were tested with the salicylaldehyde test and subjected to FTIR and zeta potential measurements.
