A core-shell plasmonic nanogapped nanostructured material is provided. The core-shell nanogapped nanostructured material has a core and at least one shell surrounding the core, wherein the at least one shell comprises a first layer comprising a polymer having a catechol group, wherein the first layer defines the nanogap in the core-shell plasmonic nanostructured material, and a second layer comprises a metal disposed on the first layer. A method of preparing the core-shell plasmonic nanogap nanostructured material, and use of the core-shell plasmonic nanogap nanostructured material are also provided. As an embodiment, a polydopamine covalently bonded to a Raman probe or a fluorescent probe is used to prepare the first layer of the shell in said core-shell plasmonic nanogap nanostructured material, thereafter a gold shell is deposited onto the polydopamine to form a second layer of the shell. In present invention, it is demonstrated that the method is highly versatile and can be used for different core materials, including magnetic Fe3O4 nanoparticles and metal-organic frameworks (MOF) nanoparticles. The potential application of said core-shell plasmonic nanogapped nanostructured in sensing and theranostics is also demonstrated.
