Nanoparticle-enhanced ultrahigh-resolution surface plasmon resonance biosensors

The present study proposes the use of a novel optical biosensor with Au nanoclusters embedded in a dielectric film to achieve a 10-fold improvement in the resolution performance. The proposed optical biosensor based on the attenuated total reflection (ATR) method excites both the surface plasmons (SPs) and particle plasmons (PPs) to enhance the local electro-magnetic field by controlling the size and volume fraction of the embedded Au nanoparticles to increase the resolution of the device. A co-sputtering method utilizing a multi-target sputtering system is used to fabricate the present dielectric films (SiO₂) with embedded Au nanoclusters. It is shown that the sensitivity of the developed SPR biosensor can be improved by adjusting the size and volume fraction of the embedded Au nanoclusters in order to control the surface plasmon effect. The present gas detection and DNA hybridization experimental results confirm that the proposed Au nanocluster-enhanced SPR biosensor provides the potential to achieve an ultrahigh-resolution detection performance of approximately 0.1 pg/mm² surface coverage of biomolecules.