Nanoporous gold leaves: Preparation, optical characterization, and biosensing capabilities

The preparation, optical characterization and plasmonic biosensing properties of self-standing nanoporous gold leaves are presented. Respect to the bulk gold, the material shows metallic behaviour at higher wavelengths and a lower imaginary part of the dielectric constants. The plasmonic properties in the near infrared range have been investigated probing the resonance shift after a self-assembling monolayer functionalization. Due to a great increase of the active surface the presence of an organic molecule adsorbed on its surface leads to important optical responses. This demonstrates how nanoporous gold reveals benefits for better reaction efficiency and detection sensitivity and how plasmonic properties in the near-IR range can assure employment in plasmonic devices.