Amino acid-modified graphene oxide magnetic nanocomposite for the magnetic separation of proteins

Abstract

A novel amino acid-modified graphene oxide magnetic nanocomposite was successfully synthesized for the magnetic separation of proteins. The extraction capacity was influenced by several parameters including the type of amino acid, the solution pH value, the addition of electrolyte, the extraction time and the protein concentration. The nanocomposite showed excellent extraction capacity for bovine hemoglobin (868.3 mg g⁻¹). By adsorbing bovine hemoglobin, bovine serum albumin, ovalbumin and lysozyme, the nanocomposite had a better performance than magnetic graphene oxide in the extraction of bovine hemoglobin and lysozyme, owing to the intensive electrostatic interaction. The proposed nanocomposite could be easily recycled and reused more than three times. Moreover, the proposed method was successfully applied to selectively extract bovine hemoglobin in acid protein mixtures and real samples.