Biomedical Engineering Reference
In-Depth Information
0.8
(b)
0.6
2
0.4
4
5
6
7
0.2
0.0
300
400
500
600
700
800
Wavelength (nm)
Figure 10.14
Changes in surface Plasmon resonance peaks (1) Au (2) SiO2@Au (3)
SiO2@Au + 0.1 ppm Cd2+ (4) SiO2@Au + 1 ppm Cd2+ (5) SiO2@Au + 2 ppm Cd2+ (6)
SiO2@Au + 5 ppm Cd2+ (7) SiO2@Au + 10ppm Cd2+.
Figure 10.15
(a) TEM image of SiO2@Au core-shell nanocomposites and (b) SEM image
of aggregated core-shell particles on addition of 0.01 ppm Cd2+ ions.
a very good technique to investigate the interactions at a molecular level.
In Figure 10.16, the Raman spectra of Au and SiO2@Au are shown. h e
sensitivity of these surfaces, however, is quite low and failed to show any
detectable signal of Au or SiO2@Au covered ITO surfaces. A decrease in
intensity for Au is noticeable when 5 ppm Cd2+ ions are present and when
SiO2@Au is 0.1 ppm.
Surface-enhanced Raman spectroscopy is also able to detect many
kinds of chemical agents as long as diagnostic peak exists for that material.
Gold nanowire sensors able to detect ppb levels of Hg in water have been
developed.
