Fiber Optical Evanescence Wave Biosensor using Enhanced Surface Plasmon on Nano-Gold Particles

• Main Authors: Cheng-Hau Chen, 陳正豪
• Other Authors: Huihua Kenny Chiang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/37492794404679262726

碩士 === 國立陽明大學 === 生醫光電工程研究所 === 93 === The evanescent wave fiber optic biosensors (EWFOBS) have the advantages of low cost, compact design and real-time in-situ monitoring for bio-molecular interaction. In this study, we utilize the BOE solution (dilute hydyofluorid acid) to etch the 400 μm, 5cm active region silica optical fibers, and to modify the surface of optical fiber with 3-aminopropyltriethoxysilane (APTS). In the evanescent field adjacent to the surface of fiber, fluorescent indicators Alexa Fluor 488 that is related to the concentration of the target analytes are detected by the structure in sandwich immunofluorescence assay. We propose and set up a EWFOBS system. The different concentration of analytes combine with fluorescent dyes conjugation, proportional to scattering fluorescence signals on the flank of the fiber are measured. Preliminary experiments have shown that the surface of the fiber are very flatness, it means that the evanescent wave is very uniform onto the surface, and we can control the etching depth exactly. The etching rate is 7.8958μm/hr now. The sensitivity in estimation is 0.1μg/mL for FITC and 50ng/mL for IgG–Anti rabbit IgG. The aqueous sample in all detection is 1mL now. The chemical kinetics calculations in this thesis are assessed in the time slot of 10 minutes, and we can obtain the association constant (ka), dissociation constant (kd) and affinity constant (K) are 2.925×106M-1s-1, 7.643×10-3s-1 and 3.83×108M-1 M-1 for IgG–Anti rabbit IgG respectively. For fluorescent signal enhancement, the magnification and sensitivity are 122%, 10ng/mL and 58%, 50ng/mL by 5nm self-assemble monolayer and 10nm self-assemble monolayer (SAM) respectively. The parameters of kinetics are fit the typical range of commercial products, and we can expect this system to be capable of applying on in-vivo clinical detection in near future.