Сore–shell magnetite–gold nanoparticles: Preparing and functionalization by chymotrypsin

In this work we present the results of the synthesis of magnetite–gold nanoparticles with a core–shell structure. The preparation is carried out in several stages: synthesis of the core, coating with a gold shell, purification of magnetite–gold particles from an uncoated magnetite, and functionalization of the surface with sulfur-containing ligands. The conditions needed for the functionalization of nanoparticles with lipoic acid and mercapto-methoxy polyethylene glycol are indicated in detail, making it possible to determine the optimal conditions needed to achieve an efficient purification and a maximum concentration of the particles in a solution required for biological tests. The possibility of remotely controlling the chymotrypsin properties using an alternating magnetic field has been demonstrated by the example of magnetite–gold nanoparticles. The magnetite–gold nanoparticles which we have obtained are promising for future biomedical applications.