Structural and magnetic characteristics of carboxymethyl dextran coated magnetic nanoparticles: From characterization to immobilization application

Abstract

MNPs were synthesized with co-precipitation of ferrous and ferric ions. Carboxymethyl dextran (CMD) was covalently bound to MNPs and the influence of different concentrations on characteristics of CMD coated magnetic nanoparticles (CMD-MNPs) was studied. Different concentrations of CMD were applied into synthesis process. The surface morphology of CMD-MNPs was monitored by scanning and transmission electron microscopy, where their spherical shape was confirmed. Fourier transform infrared spectroscopy displayed characteristic bonds that confirmed the presence of CMD hydroxyl and carboxyl groups. Thermogravimetric analysis displayed a weight loss, which confirmed the coating weight of CMD. ζ-potential measurements revealed negatively charged hydroxyl groups of CMD, and polydispersity index (PdI) showed the most consistent sizes of CMD3-MNPs. Electron paramagnetic resonance and magnetization measurements confirmed a ferromagnetic system for all CMD-MNPs. Prepared CMD3-MNPs were used as carriers for immobilization of enzyme alcohol dehydrogenase (ADH). Immobilization was carried out at two different temperatures (20 °C and 4 °C) and thermal stability at 20 °C and 40 °C after 24 h was studied. Prepared CMD-MNPs exhibit a layer of CMD coating that provides proper magnetic and structural properties and can therefore be functionalized and used in bioactive compound immobilization, such as ADH.