Authors: R.T. Reza, C.A. Martínez Pérez, C.A. Rodriguez Gonzalez, D.B. Baques, P.E. García-Casillas
Affilation: Universidad Autónoma de Ciudad Juárez, Mexico
Pages: 534 - 538
Keywords: nanoparticles, magnetite, chemical co-precipitation, protein separation
Nowadays, magnetic particles are of great interest to different research areas, such as magnetic separation techniques, biotechnology, catalysis, magnetic resonance imaging, magnetic fluids and data storage, among others . The application of magnetic particles involves a strict control of the particle characteristics: chemical composition, particle size and size distribution, crystalline structure, stability of magnetic properties, surface morphology, adsorption properties and low toxicity, etc. In this work, the synthesis of magnetite nanoparticles by a three variant chemical co-precipitation methods that involves reflux and aging conditions as well as slow and rapid injection techniques was investigated. The influence of the synthesis technique onto particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Average particle size from 16 nm, 27 nm and 200 nm were obtained. The rapid injection technique produced the smallest particle size while the co-precipitation with reflux and aging method generated the largest. All three types of magnetite nanoparticles had a superparamagnetic behavior and their saturation magnetization is influenced by the particle size. Values of 56, 67 and 78 emu/g were obtained for the 16 nm, 27 nm and 200 nm magnetite particles, respectively. The protein adsorption was improved by using a surface coating. The silica-aminosilane coating showed the best performance followed by the aminosilane coating. The silica coating showed the lowest adsorption for all three particle sizes. The nanoparticles were characterized by Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Vibrating Sample Magnetometry (VSM) and X-Ray Diffraction (XRD). Protein adsorption was determined using a visible light spectrometer.