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

Concanavalin A (Con A) was successfully bound onto Fe₃O ₄ 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 ± 3.86 nm. The size and structure of Fe ₃O₄ 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 Fe ₃O₄ MNPs was determined to be about 10 wt%. Furthermore, the Con A-bound Fe₃O₄ MNPs were found to be quite efficient for the fast adsorption of lactoferrin. The equilibrium was achieved within 5 min 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 59.2 mg/g and 0.0103 L/mg, respectively. In addition, by SDS-polyacrylamide gel electrophoresis, the capability of Con A-bound Fe ₃O₄ MNPs for the selective adsorption of lactoferrin was further confirmed.