Colloidal gold-modified optical fiber for chemical and biochemical sensing.
A novel class of fiber-optic evanescent-wave sensor was constructed on the basis of modification of the unclad portion of an optical fiber with self-assembled gold colloids. The optical properties and, hence, the attenuated total reflection spectrum of self-assembled gold colloids on the optical fiber changes with different refractive index of the environment near the colloidal gold surface. With sucrose solutions of increasing refractive index, the sensor response decreases linearly. The colloidal gold surface was also functionalized with glycine, succinic acid, or biotin to enhance the selectivity of the sensor. Results show that the sensor response decreases linearly with increasing concentration of each analyte. When the colloidal gold surface was functionalized with biotin, the detection limit of the sensor for streptavidin was 9.8 x 10(-11) M. Using this approach, we demonstrate proof-of-concept of a class of refractive index sensor that is sensitive to the refractive index of the environment near the colloidal gold surface and, hence, is suitable for label-free detection of molecular or biomolecular binding at the surface of gold colloids.
Cheng
Shu-Fang
SF
Department of Chemistry, National Chung Cheng University, Ming-Hsiung, Chia-Yi, Taiwan 621, R.O.C.
Chau
Lai-Kwan
LK
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods*; D005336:Fiber Optic Technology / Q000295:instrumentation* / Q000379:methods*; D017979:Gold Colloid; D055100:Optical Fibers; D012680:Sensitivity and Specificity; D013395:Sucrose / Q000737:chemistry; D020349:Surface Plasmon Resonance; D013997:Time Factors; D014867:Water / Q000737:chemistry
D017979:Gold Colloid; D014867:Water; D013395:Sucrose