Chitosan functionalized gold-nickel bimetallic magnetic nanomachines for motion-based deoxyribonucleic acid recognition.

In this present study, the preparation of chitosan functionalized gold‑nickel wire nanomachines (nanomotors) (CS@Au-Ni NMs) for motion-based double-stranded deoxyribonucleic acid (dsDNA) recognition and detection was described. Synthesis of the nanomachines was accomplished by Ni layer formation using direct current (DC) magnetron sputtering over electrochemically deposited Au wires. Subsequently, biopolymer chitosan was dispersed onto this bimetallic layer by drop casting which could provide a novel and functional surface for leading bio-applications. CS@Au-Ni NMs were characterized via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and zeta potential analysis methods for the elucidation of structural morphology, elemental composition and electrophoretic mobility. On account of presenting the application of these magnetic nanomachines, they were interacted with different concentrations of dsDNA and the changes in their velocities were investigated. The speed CS@Au-Ni NMs were measured as 19 μm/s under 22 mT magnetic field. These magnetically guided nanomachines demonstrated a practical and good sensing ability by recognizing dsDNA between 0.01 mg/L and 10 mg/L. Electrochemical characterization was also performed to identify the surface characteristics. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments presented the interaction of the NMs with dsDNA by indicating the convenient recognition.