奈米電漿子感測技術於生物分子之功能分析

Nanoplasmonic Sensing for Biomolecular Function Analysis

簡汎清(Fan-Ching Chien)

指導教授 ： 孫慶成 ； 陳顯禎

國立中央大學/理學院/光電科學研究所/博士(2006年)

摘要

表面電漿子共振（surface plasmon resonance，SPR）生物感測技術於界面環境變化具有高的靈敏度且不需外加任何標記等優勢，目前已廣泛的被應用於生物分子交互作用分析（biomolecular interaction analysis，BIA）研究，傳統SPR生物感測技術的偵測極限已達1 pg/mm2的生物分子表面覆蓋率，不過仍難以直接偵測極微小分子量或極低濃度分子間交互作用。另外，SPR只能提供BIA之動力學資訊，然一完整對生物分子辨識系統除提供動力學分析外，更應具有偵測構形改變之能力。
因此，本論文研究發展奈米電漿子（nanoplasmons）技術來解決上述兩個關鍵問題。分別利用圖樣化金奈米粒子或次波長（subwavelength）結構來操控粒子電漿子（particle plasmons，PPs）或局域表面電漿子（localized surface plasmons，LSPs）以提昇感測靈敏度，控制嵌入金奈米團簇（nanoclusters）於介電質膜層的粒徑與體積分率以強化電漿子生物感測器約有十倍的靈敏度並可實現極微量待測分子（<200 Da）交互作用的直接偵測生物分析程序且不需大分子量的競爭分子或額外標記；研發次波長光柵建構耦合波導表面電漿共振（coupled waveguide-surface plasmon resonance，CWSPR）生物感測器不僅維持感測靈敏度且可改善量測精度，沒有傳統衰逝全反射（attenuated total refelection，ATR）耦合器的限制，其感測系統於蛋白微陣列晶片或影像系統應用上將較為靈活和可行。此外，研發一個建構於Kretschmann組態的CWSPR生物感測器具有同時耦合SPR模態及波導模態的雙CWSPR模態，除了可動態提供高靈敏的動力學分析之外，更具有直接即時地監測蛋白分子構形變化的能力。因此，對於快速診斷，藥物研發與蛋白質體學（proteomics）研究等將可建立嶄新的奈米電漿子之生物分子功能分析平台。

關鍵字

生物分子交互作用分析 ； 生物感測器 ； 次波長光柵 ； 耦合波導表面電漿共振 ； 粒子電漿子 ； 表面電漿子 ； 奈米電漿子

並列摘要

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.

並列關鍵字

subwavelength grating ； biomolecular interaction analysis ； biosensor ； nanoplasmons ； coupled waveguide-surface plasmon resonance ； surface plasmons ； particle plasmons

參考文獻

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