Active and stable palladium nano-thin-film structure development for rapid and direct biomolecules conjugation and sensing

Metal atoms on surface edges or with specific coordinates possess high surface potentials and serve as core atoms for organic molecule bonding. Unlike self-organized or surface modified nanoparticles, these active metal nanostructures may lose their activity by surface self-diffusion process. It is challenging to create a metal surface structure which possesses both active and stable properties. However, a surface template with native nano-roughness may solve this dilemma. In this study, a PET substrate has been selected for metal atoms absorption and a stable and active Pd nano-thin-film (NTF) surface has been developed. Further studies indicated that the surface contains an (1,1,1) like structure and Pd-NTF growth followed a Stranski-Krastanov-like growth model. This nanostructure thin-film (Pd NTF-PET) electrode has been developed for electrochemical impedance spectroscopy (EIS) usage. Both DNA and protein can be immobilized on the Pd NTF-PET electrodes directly, within 15 min and its biosensing sensitivity was as low as 0.1 ng per-test in 1 µl. In summary, we have developed an active and stable Pd NTF-PET electrode for biosensing applications.