| dc.description.abstract | Surface plasmon resonance (SPR) biosensing has become a standard practice in the investigation of biomolecular interaction analysis (BIA), because it is highly sensitive to the resonance condition on the sensing surface caused by environmental changes and do not require any extrinsic labeling. However, the detection sensitivity of the current practical SPR biosensors is limited to 1 pg/mm2 surface coverage of biomolecules, which is insufficient for the monitoring of low concentrations of small biomolecular analytes. In addition, the conventional SPR biosensor only can provide a high-sensitivity kinetic analysis in the BIA, not conformational information. However, a more powerful biorecognition system is required not only to provide the kinetic analysis, but also to have the capability of monitoring biomolecular conformational change or trend.
Therefore, in this dissertation, nanoplasmons technology was reserched and developed to overcome two above critial tasks. Patternized gold nanoparticle-enhanced plasmonic effects and subwavelength metal nanostructure are used to manipulate particle plasmons (PPs) and localized surface plasmons (LSPs) and enhance the biosensor sensitivity, respectively. The sensitivity of plasmonic biosensors was enhanced about 10-fold by controlling the size and volume fraction of the embedded Au nanoclusters in dielectric films and a direct detection bioassay can be adopted to analyze the interactions of tiny analytes (< 200 Da) in low concentrations without the need for high molecular weight competitors or explicit labeling. Furthermore, a coupled waveguide-surface plasmon resonance (CWSPR) biosensor constructed with subwavelength grating structure not only retains the same sensing sensitivity as that of a conventional SPR device, but also yields sharper dips in the reflectivity spectrum and therefore provides an improved measurement precision. Moreover, without the limitation of a conventional attenuated total reflection (ATR) coupler and with the help of normal incidence, the system is more flexible and feasible for protein microarray and imaging applications. In addition, a CWSPR biosensor based on the Kretschmann configuration couples the surface plasmon mode and waveguide mode and generates two CWSPR modes in the reflectivity spectrum. The CWSPR device not only provides the high-sensitivity kinetic data dynamically, but also has the capability of monitoring biomolecular conformational change. Hence, the nanoplasmonic sensing will be novel biosensing platform for biomolecular function analysis in the fast diagnostic, drug discovery, and proteomics study. | en_US |