Surface active flexible palladium nano-thin-film electrode development for biosensing

Metal atoms on surface edges or with specific coordinates possess high surface potentials, and serve as core atoms for organic molecule bonding. However, these active metal atoms may lose their activity by self-diffusion on the surface. A polyethylene terephthalate (PET) substrate provided a stable rough surface in nanoscale for metal atoms absorption and formation of a stable and active nano-thin-film (NTF) surface. However, the NTF surface roughness decreased with increasing thickness of palladium (Pd) granules, indicating that the surface growth of the Pd film followed a Stranski-Krastanov-like growth model. Therefore, the proper thickness of Pd-NTF on PET substrate (Pd NTF-PET) was developed for electrochemical impedance spectroscopy (EIS). Protein was immobilized on the Pd NTF-PET electrodes within 15 min and its biosensing sensitivity was as low as 0.1 ng per-test in 1 μl. We expect that the developed Pd NTF-PET electrode can be used for other biosensing applications as well.