| Summary: | 碩士 === 國立中興大學 === 化學系所 === 97 === Large area, stable, and selective gold nanoparticles monolayer have been successfully fabricated on glass substrates via. the novel centrifugal method. By virtue of the carboxylic acid group which functionalized on gold nanoparticles surface, the density and arrangement of gold nanoparticles monolayer on glass substrates would be depended on pH adjustment due to the repulsive force between gold nanoparticles.
The monolayer was characterized by UV-visible spectrophotometer (UV-Vis.), field-emission scanning electron microscopy (FE-SEM), and high resolution transition electron microscopy (HR-TEM). Several factors, such as refractive index, dielectric constant, and polarity which affected the absorption bands of monolayer were discussed by UV-vis. Spectra. We examine several solvents to demonstrate the tendency of absorption bands in different environment. In polar medium, absorption band tend to blue shift as refractive index is increasing, but absorption band is unconcerned with refractive index in non-polar medium. Besides, absorption bands are proportional to dielectric constant.
Optical properties are applied to streptavidin biosensor. Peak position tends to blue shift as streptavidin adsorbed on monolayer due to refractive index and dielectric constant changed. By way of real-time detection, we find out that initial adsorption rate is proportional to concentration of streptavidin, and a detection limit of 1 ppm for streptavidin.
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