Excitation laser wavelength was 532 nm. The black spectrum was taken right before adding Ni particles, and the red, green, and blue spectra were taken 60, 120, and 180 min, respectively, after adding Ni particles. Substantial PL enhancements in the aqueous RNA-SWCNT solution after metal particles were introduced can be seen in Figure 4a,b,c where PL spectra before and after the introduction of Au, Co, and Ni particles,

respectively, were Androgen Receptor Antagonist compared. However, the introduction of metal particles into the solution did not have any effect on the Raman spectrum as can be seen in Figure 4d,e,f. Figure 4 Selleckchem AG-881 Photoluminescence and Raman spectra of the RNA-functionalized SWCNTs before and after adding metal particles. PL spectra show substantial enhancement after adding (a) gold, (b) cobalt, and PRIMA-1MET concentration (c) nickel particles. Raman spectra do not show any change after adding (d) gold, (e) cobalt, and (f) nickel particles. Excitation laser wavelength was 514 nm

for (a, b, d, and e) and 532 nm for (c and f). All the ‘after’ spectra were taken 180 min after adding metal particles. In order to see that the observed metal-particle-induced PL enhancement is a unique phenomenon for the RNA-functionalized SWCNTs, we performed the same experiments on the DNA-functionalized SWCNTs. The results, as shown in Figure 5, are almost the same as those on the RNA-functionalized SWCNTs. Finally, we did the same experiments on the DOC-functionalized SWCNTs. However, the PL spectrum as well as the Raman spectrum remained unchanged after the metal particles were introduced into the DOC-SWCNT solution, as shown in Figure 6. Figure 5 Photoluminescence and Raman spectra of the DNA-functionalized SWCNTs before and after adding metal particles.

PL spectra show substantial enhancement after adding (a) gold, (b) cobalt, and (c) nickel particles. Raman spectra do not show any change after adding (d) gold, (e) cobalt, and (f) nickel particles. Excitation laser wavelength was 532 nm for (a, c, d , and f) and 514 nm for (b and e). All the ‘after’ spectra were taken 180 min after adding metal particles. Figure 6 Photoluminescence and Raman spectra of the DOC-functionalized SWCNTs before and after adding metal particles. Both Raman spectra do not show any change after adding (a and d) gold, (b and e) cobalt, and (c and f) nickel http://www.selleck.co.jp/products/BafilomycinA1.html particles. Excitation laser wavelength was 532 nm for all spectra. All the ‘after’ spectra were taken 180 min after adding metal particles. The atomic force microscopy (AFM) results (see Additional file 1) showed that the metal particles were not adsorbed on the SWCNTs. In fact, the size of the metal particles is a few micrometers whereas the diameter of the SWCNTs is approximately 1 nm. Thus, the metal particles are too big to be adsorbed on the SWCNTs. The metal particles just sedimented at the bottom of the cuvette and remained there during the optical measurements.