Preparation And Characterization Of Carboxyl-group Functionalized Magnetic Nanoparticles And Its Application In Purification Of Plasmid DNA

Magnetic nanoparticles (MNPs) are one of most promising complex materials in biology and biomedicine, typically iron oxide (Fe₃O₄ or γ-Fe₂O₃) based, with the surface tailored with surfactants or polymers through a coating process or encapsulation. Like magnetic microspheres, magnetic nanoparticles possess both functional groups on the surface and superparamagnetic phenomena. Besides, their unique properties such as small particle size, high surface/volume ratio, fast movement and long-time suspension in biological environment render them an important tool for both biological and biomedical analysis. Therefore, carboxylated magnetic nanoparticles were synthesized and the synthesized products were used for the purification of plasmid DNA from bacterial cells.Superparamagnetic iron oxide nanoparticles were prepared by co-precipitation method at the presence of NaOH. The optimal working condition for the preparation of superparamagnetic iron oxide nanoparticles was investigated by using Orthogonal test method. The influences of heat treatment parameters such as Fe²⁺/Fe³⁺ ratio, nucleation and nucleus growth temperature and time on particle size and magnetic properties were studied. The particles were characterized by transmission spectroscopy, X-ray diffraction spectroscopy, fourier transformation infrared spectroscopy, thermogravimetric analysis and vibration sample magnetometry. The optimal combination of iron ratio, temperature and reaction time for the preparation of supeparamagnetic nanoparticles was n(Fe²⁺) :n(Fe³⁺)=1: 1. 65, 63 ℃ and 60 min, respectively. The results demonstrated that particles displayed a high...