Intensity sensitivity of gold nanostructures and its application for high-throughput biosensing.

A new microarray for dynamical studies of surface biomolecular interactions without fluorescent labeling is proposed. We employed gold nanostructures to excite surface plasmons on the microarray surface and detected the intensity changes in the extraordinary transmission. The calculation and measurement results indicate that the nanoslit array has an intensity sensitivity much higher than the nanohole array due to its narrower resonant bandwidth. In addition, the sensitivity is increased as the slit width decreases. For 35 nm slit width, the intensity sensitivity reaches to approximately 4000%/RIU, two times larger than the slit width larger than 150 nm. Using the intensity changes, we demonstrate a 10 x 10 microarray for real-time measurements of antigen-antibody and DNA-DNA interactions.