Research PaperDetection of diclofenac molecules by planar and nanostructured plasmonic sensor substrates

- Low-cost sensor substrates can be fabricated by means of nanoimprint lithography.
- Successful immobilization of diclofenac on gold surfaces is proved by XPS and SPR.
- Monoclonal anti-diclofenac antibody binds specifically to immobilized diclofenac.
- Immunobinding can be detected by standard SPR and nanostructured sensor substrates.
- Carboxylated PEG is well-suited to suppress unspecific binding on gold surfaces.

Surface plasmon resonance (SPR) sensors are well-established and widely used in the field of environmental and life sciences. To overcome the limitation of SPR sensors to applications in the laboratory environment initial studies on a low-cost nanostructured sensor substrate fabricated by nanoimprint lithography for the development of a SPR-based on-site biosensor system were conducted. For this purpose, diclofenac molecules were successfully immobilized both on planar and nanostructured gold sensor substrates, which was proved by XPS and SPR measurements. For the latter substrates, a specific binding between an anti-diclofenac antibody and immobilized diclofenac can be observed in form of a localized surface plasmon resonance shift in the optical transmission spectrum. The results show that our low-cost sensor substrate is wellsuited as transducer element for future SPR-based biosensors.