Ant colony optimization ha
In general, comparatively selleckchem thick gold films (t �� 15 nm) created with typical deposition rate (>1? /sec) have a continuous morphology with slight roughness  and exhibit a minimum absorbance near 500 nm.Thin gold films (t < 10 nm) that are deposited slowly (<0.1 ?/sec) show an extinction maximum attributed to excitation of the localized surface plasmon (LSP) in the near IR range. After heat treatment of the intact gold NI film, the LSP band of the gold NIs shifts to the visible range and consequently, the extinction band appears near 560nm , similar to the extinction band of gold nanoparticles immobilized on transparent substrates [1,2] (Figure 1). The annealing effect on the extinction spectra of Inhibitors,Modulators,Libraries gold NI films originates from the changes in the morphology of the gold films.
Figure 2 shows the AFM images of the gold films before and after heat treatment. The average height and diameter of the gold NI increased from 5.3 nm to 17.3 nm and from 29.5 nm to 67.2 nm, respectively, as a result of heat treatment. These results are in agreement Inhibitors,Modulators,Libraries with those of previous studies [4,10].Figure 1.Extinction spectra of gold films obtained from different processes.Figure 2.2-D AFM images of (a) non-annealed gold NI film and (b) annealed gold NI film. The scan ranges are 1 �� 1 ��m2.In the detection using LSPR, the peak shift or amplitude of the LSP band is generally measured as the local environment of metal nano structure is changing. In case of measuring the wavelength shift of the LSP band, the definition of the spectral centroid of the LSP band using a proper baseline is more effective than tracing its peak position .
Inhibitors,Modulators,Libraries The centroid (��cent.) of an extinction spectrum Inhibitors,Modulators,Libraries (��(��)) as a function of wavelength (��) is given by��cent.=�Ҧ�1��2��(��(��)?��B)d�ˡҦ�1��2(��(��)?��B)d��(1)where ��B is the baseline value, which is chosen as the Entinostat half-maximum of the extinction spectrum, and ��1 and ��2 are the wavelengths at which the baseline intersects the extinction spectrum.When the ambient medium for the bare NIs was changed from air to DI water, the change in the centroid position (����cent.) of the LSP band was 28 nm (the data not shown). The detection sensitivity of the refractive index with the gold NI array fabricated in this study was not largely different from the detection sensitivity reported in previous studies that have examined similar nano structures [1,2].
2.2. Signal Amplification using Enzymatic Precipitation in Immunoassay with Gold NI ChipFigure 3 shows the LSPR spectra of gold NIs on a glass wafer measured after each step of the immobilization and binding process (described in the experimental section). As shown in this figure, the intensity of the maximum extinction selleck chem increased and the ��cent. of LSPR band shifted to longer wavelengths after each subsequent modification step of the gold NI surface.