Direct binding of Concanvalin A onto iron oxide nanoparticles for fast magnetic selective separation of lactoferrin

Abstract

Concanavalin A (Con A) was successfully bound onto Fe3O4 magnetic nanoparticles (MNPs) via carbodiimide activation as a magnetic nano-adsorbent for glycoprotein separation. The resulting Con A-bound Fe3O4 MNPs were nearly superparamagnetic with a mean diameter of 11.74±3.86nm. The size and structure of Fe3O4 MNPs had no significant changes after Con A binding. The binding of Con A on the surface of Fe3O4 MNPs was confirmed by the analysis of Fourier transform infrared spectroscopy. From the thermogravimetric analysis and the concentration change of Con A in the binding solution, the weight percentage of Con A in the typical Con A-bound Fe3O4 MNPs was determined to be about 10wt%. Furthermore, the Con A-bound Fe3O4 MNPs were found to be quite efficient for the fast adsorption of lactoferrin. The equilibrium was achieved within 5min and the adsorption data for lactoferrin obeyed the Langmuir isotherm equation. At pH 7 and 25°C, the maximum adsorption capacity and equilibrium constant were 59.2mg/g and 0.0103L/mg, respectively. In addition, by SDS–polyacrylamide gel electrophoresis, the capability of Con A-bound Fe3O4 MNPs for the selective adsorption of lactoferrin was further confirmed.