Synthesis and Characterization of Amino-Modified FMNPs

Silica-coated FMNPs were synthesized and evaluated according to our previous reports¹⁶ (link)^,30 (link). Ethanol (95 mL) and 2 mL of 3-aminopropyltriethoxysilane (APS) were mixed and allowed to react at room temperature for 24 h. Amino-modified FMNPs were separated using permanent magnet, washed with deionized water three times, and stored for further use. The prepared amino-modified FMNPs were characterized by a transmission electron microscope (TEM). The fluorescent and magnetic properties of amino-modified FMNPs were also determined using the photoluminescence (PL) spectra (Perkin Elmer LS 55 Spectrofluorimeter, PerkinElmer, Waltham, MA, USA) and superconducting quantum interference device magnetometer (PPMS-9 T, Quantum Design, Beijing, China), respectively. The zeta-potential value of amino-modified FMNPs was measured with particle sizing systems (NICOMP 380ZLS, PSS, Port Richey, FL, USA).