Bifunctional Au-Fe₃O₄ Nanoparticles for Protein Separation

Abstract

In this article, we report the synthesis of bifunctional Au-Fe(3)O(4) nanoparticles that are formed by chemical bond linkage. Due to the introduction of Au nanoparticles, the resulting bifunctional Au-Fe(3)O(4) nanoparticles can be easily modified with other functional molecules to realize various nanobiotechnological separations and detections. Here, as an example, we demonstrate that as-prepared Au-Fe(3)O(4) nanoparticles can be modified with nitrilotriacetic acid molecules through Au-S interaction and used to separate proteins simply with the assistance of a magnet. Bradford protein assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis were performed to examine the validity of the separation procedure, and the phosphate determination method suggested that the as-separated protein maintained catalytic activity. This result shows the efficiency of such a material in protein separation and suggests that its use can be extended to magnetic separation of other biosubstances. Moreover, this synthetic strategy paves the way for facile preparation of diverse bifunctional and even multifunctional nanomaterials.

Synthesis, Functionalization, and Design of Magnetic Nanoparticles for Theranostic Applications

“…[367] Currently, there have been considerable number of reports on synthesizing magnetic nanoparticles covered by gold through microemulsion, [368] chemical reduction, [369] coprecipitation, seed mediated growth, [370] selfassembly, [371] sonochemical reduction, [372] thermal decomposition, [91] and laser irradiation [373] approaches. Bao et al [374] have also reported synthesis of gold-magnetite composites involving discrete gold nanoparticles on magnetite surface which can be useful for applications such as protein separation, optical imaging, or catalysis, where a full coating is not required. Overlaying of gold can be facilitated by attachment of gold seeds that form a protective layer to increase the particle stability against particle aggregation and make them resistant to chemical attacks.…”

Functional Inorganic Nanohybrids for Biomedical Diagnosis

“…The strong magnetism of the plasmonic-magnetic nanohybrids and the CO superior catalytic activity of the Au-Co coreshells were showed as a result of incorporating magnetic heterometals into gold particles. The authors [22] also synthesized bifunctional Au-Fe3O4 nanohybrids through the conjugation of Au particles to thiol-modified Fe3O4 nanoparticles. Lysine contained both amino and carboxylic groups played dual roles as both linker and capping agent in attaching metals on Fe2O3 particles.…”

A Facile and Green Synthetic Route for Preparation of Heterostructure Fe3O4@Au Nanocomposites

“…Magnetic iron oxide nanoparticles (MNPs) have attracted considerable interest due to its superparamagnetism, and offered many exciting opportunities in biology and biomedicine, including magnetic resonance imaging, magnetic hyperthermia therapy, biosensor, separation and purification of protein and cell [1][2][3][4][5]. Meanwhile, the gold NPs have been extensively used in biosensor, surface enhanced Raman spectroscopy, and therapy applications, due to its well-known catalytic activity, optical properties, chemical functionality, and biocompatibility [6][7][8].…”