1. INTRODUCTIONCore–shell nanocomposites have attracted widespreadattention in recent years due to their special structures∗Author to whom correspondence should be addressed.and properties. Composite nanoparticles with iron oxideas core and gold as coating have also become one of theresearch hotspots in the field of core–shell nanocomposites and super-paramagnetic iron oxides have been appliedto the fields of biological detection and imaging, targeted