Synthesis of Ni@Au core-shell magnetic nanotubes for bioapplication and SERS detection

Ni@Au core-shell nanotubes were synthesized using a two-stage method including Ni nanotubes growth in pores of PET template and their electroless wet-chemical functionalizing with gold. The structure, morphology, chemical composition, surface condition and magnetic properties of Ni@Au nanotubes were comprehensively studied. Cellular cytotoxicity of Ni and Ni@Au nanotubes was evaluated demonstrating its strong reduction when nanotubes were coated with Au layer. The gold layer had a granular structure with some agglomerations resulting in surface irregularities which is advantageous for surface-enhanced Raman spectroscopy (SERS). The fundamental possibility of using the functionalized Ni@Au nanotubes as SERS substrates was demonstrated by the example of methylene blue detection for concentrations down to 10−6 M. The average enhancement factor was 104, which is sufficient for use in chemo- and biosensorics. [Display omitted] •Two-stage method of Ni@Au core-shell nanotubes synthesis was demonstrated.•Granular structure of gold layer led to irregularities on Ni NTs surface.•Covering Ni NTs with Au layer significantly reduced the toxicological effect.•Average Raman EF of SERS substrates with Ni@Au NTs for Methylene Blue detection was 104.•Possibility of Ni@Au magnetic nanotubes SERS application on the base of 10−6 M of Methylene Blue is shown.