Click chemistry: a new facile and efficient strategy for the preparation of Fe3O4nanoparticles covalently functionalized with IDA-Cu and their application in the depletion of abundant protein in blood samples

Abstract

In this study, we report a novel method to synthesize core–shell structured Fe₃O₄ nanoparticles (NPs) covalently functionalized with iminodiacetic acid (IDA) via click chemistry between the azide and alkyne groups and charged with Cu²⁺. Firstly, the Fe₃O₄@SiO₂ NPs were obtained using tetraethoxysilane (TEOS) to form a silica shell on the surface of the Fe₃O₄ core. The azide group-modified Fe₃O₄@SiO₂ NPs were obtained by a sol–gel process using 3-azidopropyltriethoxysilane (AzPTES) as the silane agent. Fe₃O₄@SiO₂–N₃ was directly reacted with N-propargyl iminodiacetic via click chemistry, in the presence of a Cu(I) catalyst, to acquire the IDA-modified Fe₃O₄ NPs. Finally, through the addition of Cu²⁺, the Fe₃O₄@SiO₂–IDA-Cu NP product was obtained. The morphology, structure and composition of the NPs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resulting NPs showed a strong magnetic response to an externally applied magnetic field, a high adsorption capacity and excellent specificity towards hemoglobin (Hb). In addition, the Fe₃O₄@SiO₂–IDA-Cu NPs can be used for the selective removal of abundant Hb protein in bovine and human blood samples.