Fiber-Optic Biosensors Using Light Scattering of Gold Nanoparticles

• Main Authors: yawei chu, 邱業瑋
• Other Authors: Lai-kwan Chau
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/20083728671412157939

碩士 === 國立中正大學 === 化學所 === 94 === A novel light-scattering sensing platform was constructed on the basis of modification of the unclad portion of an optical fiber with self-assembled gold nanoparticles. When excited with a Diode Pumped Laser at 532 nm, the light-scattering signal from the optical fiber changes with different refractive index of the environment near the gold nanoparticle surface. With sucrose solutions of increasing refractive index, the light-scattering signal increases linearly. The sensor resolution is 4.5*10-2 RIU. This change in the light-scattering property of gold nanoparticles in solutions of different refractive indexes has been confirmed by simulations. To increase the selectivity of the sensor, we chose three receptor-analyte pairs, biotin/streptavidin, biotin/anti-biotin, and DNP/anti-DNP, to test the sensor. With excitation by a He-Cd laser at 442 nm, results show that the light-scattering signal increases linearly with increasing concentration of each analyte. With biotin modified on the gold nanoparticle surface, the limit of detection (LOD) of the sensor for streptavidin was 8.4*10-9M. To increase sensitivity of the sensor, the sensor length was increased from 1cm to 4cm. As such, the LOD of the sensor for streptavidin lowered to 3.6*10-10M. Using a sensor length of 4cm, the LOD of the sensor for anti-biotin and anti-DNP were 6.3*10-8M and 2.9*10-9M, respectively. The effect of excitation wavelength on the sensing platform was also explored. Using excitation wavelength of 532nm instead of 442nm, the LOD of the biotin-functionalized sensor for streptavidin was 3.4*10-9M