Method screening for conjugation of the small molecules onto the vinyl-coated Fe₃O₄/silica nanoparticles: highlighting the efficiency of ultrasonication

Method development for surface functionalization of vinyl-coated iron oxide nanoparticles via [4 + 2] one-pot cycloaddition is presented in this work. Small molecules are loaded onto the surface of silica-coated magnetic nanoparticles (Fe₃O₄/SiO₂ NPs) by various methods. The main factors such as surface modification ratio, core/shell structure maintenance, spherical morphology preservation and particle size uniformity were precisely investigated by various analyses. In this regard, reflux, microwave and ultrasound wave irradiation have been well compared as three different effective methods for carrying out the cycloaddition (CA) reactions onto the surface of magnetic nanoparticles. Overall, it was concluded that the safer and faster method for this purpose is implemented by the ultrasound wave irradiation. (paper)