Biosensing Based on Surface Plasmon Resonance of Gold Nanohole and Nanoring Arrays Fabricated by a Novel Nanosphere Lithography Technique

An optical biosensor based on gold nanohole arrays was developed using a new nanosphere lithography technique. A vertical deposition method was used to deposit multilayers of a polystyrene (PS) - gold composite on a silanized glass substrate. The SEM images have shown that the gold nanohole and nanoring arrays are distributed uniformly on the substrate. The sensitivity of the gold surface plasmon resonance (SPR) band to the environment was found to be dependent on the geometry of the array. The new nanostructures have been used as platforms for rapid screening of biomolecular interactions. Fibrinogen and biotin absorption studies conducted with the functionalized gold nanostructures demonstrated the feasibility of using them to monitor biomolecular interactions. The sensitivity was found to be around 300 nmldrRIU^-1, which is adequate for biosensing applications. The present technique has the advantage of simplicity; the structures can be prepared without any special equipment and a standard cell can be used for optical measurements.