Synthesis and characteristics of NH₂-functionalized polymer films to align and immobilize DNA molecules

We developed a method to use NH₂-functionalized polymer films to align and immobilize DNA molecules on a Si substrate. The plasma-polymerized cyclohexane film was deposited on the Si substrate according to the radio frequency plasma-enhanced chemical vapor deposition method using a single molecular precursor, and it was then treated by the dielectric barrier discharge method in a nitrogen environment under atmospheric pressure. Changes in the chemistry of the surface functional groups were studied using X-ray photoelectron spectroscopy and Fourier transformed infrared spectroscopy. The wettability of the surfaces was examined using dynamic contact angle measurements, and the surface morphology was evaluated using atomic force microscopy. We utilized a tilting method to align λ-DNA molecules that were immobilized by the electrostatic interaction between the amine groups in NH₂-functionalized polymer films and the phosphate groups in the DNA. The DNA was treated with positively charged gold nanoparticles to make a conductive nanowire that uses the DNA as a template. We observed that the NH₂-functionalized polymer film was useful for aligning and immobilizing the DNA, and thus the DNA-templated nanowires.