In this study, a novel fabrication method for high aspect ratio magnetic Au/Ni coaxial nanorod arrays is proposed. It is expected that the stiffness of the gold shell could be supported by the core nickel rod. Furthermore, a magnetic force can be employed to manipulate the motion of the coaxial nanorod arrays. The fabrication procedures include: AAO template preparation, working electrode coating, nickel electrodeposition, alumina etching, and gold-plating by an electroless nickel immersion gold (ENIG) process.
Experimental results demonstrated that the proposed method in this study could synthesize high aspect ratio magnetic Au/Ni coaxial nanorod arrays. The height of the synthesized coaxial nanorods is about 65.3 μm and the diameter of each nanorod is around 0.225 μm. Hence the aspect ratio is 290. The Au/Ni coaxial nanorod array was further used as a biosensor for the detection of glucose. The sensitivity of the proposed glucose biosensor was 225 μA/(mM·cm2) with a linear detection range of 27.5 μM to 1.38 mM. The sensitivity of the proposed Au/Ni coaxial nanorod array for glucose detection is the best among the reported works.