Antibody binding: The anti-His antibody was covalently linked to FVIOs via EDC/NHS reaction. DHCA-FVIOs (1 mg) were reacted with EDC (10 mM) and NHS (10 mM) for 15 min in MES buffer (0.1 M, pH 6.0). Then, the solution was adjusted to pH 7.4, and 5 μL of mouse monoclonal anti-His antibody was added and shaken for 2 hours. The final products were washed with PBS to remove unbound antibodies and dispersed in PBS before in vitro and in vivo testing.
Characterization: The crystal structure of magnetic nanoheaters was characterized by X-ray diffraction (XRD) patterns using a powder diffractometer (Bruker, D8 Advance, Germany). The morphology of nanoheaters was observed by scanning electron microscopy (SEM, Hitachi SU8010, Japan). The anti-His antibody-coated nanoheaters were stained with phosphotungstic acid and characterized by transmission electron microscopy (TEM, HT-7700, Japan). The hydrodynamic diameters of nanoheaters were examined by dynamic light scattering (DLS, Malvern, England). The Fe concentration of nanoheater suspensions was detected using inductively coupled plasma mass spectrometry (ICP-MS, Agilent 7900, America). The magnetization curves were determined using a vibrating sample magnetometer (VSM, BKT-4600, China).