In this work, a simple and effective strategy has been developed to synthesize gold nanocages@negative (Au NCs@COO-)-gold naocages@positive (Au NCs@(NH3+) charge on the nanocages’ (with hollow or porous structures) surfaces, based on a galvanic replacement reaction and co-reduction method of the corresponding ions. The prepared
Au@NH3+-Au@COO- nanocages have been characterized by UV–vis, TEM, and XRD. Our results show that the SERS technique is able to detect Rd3B within wide concentration range, i.e. 10-16 – 10-8 M, with lower limit of detection (LOD) being 10-16M. It demonstrates that the Au@NH3+-Au@COO- nanocages have potential applications for the detection of biomolecules, biomarkers or dye molecules to early detection and diagnosis of cancers or serious diseases, and significant reduce environmental pollution and waste water from industrial manufacture to the quality of life.