Photoluminescence of Gold Nanoparticles and Their Applications to Sensing and Cell Imaging - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 198

NPs. The as-prepared spherical 11-MUA-Au NPs of various sizes
emit light at different wavelengths within the range 500-640 nm
(Fig. 9.6A). Likewise, by controlling the molar ratio of Au and Ag ions,
11-MUA-protected Au/Ag NPs having similar sizes can be prepared;
these NPs emit light at different wavelengths within the range
456-525 nm (Fig. 9.6B).
Figure 9.6 (A) Normalized luminescence spectra of 11-MUA-Au NPs
prepared at THPC-to-HAuCl 4 concentration ratios of (a) 1.0,
(b) 2.0, and (c) 3.5. (B) Luminescence spectra of 11-MUA-Au/
Ag NPs prepared at AgNO 3 -to-HAuCl 4 molar ratios of (a) 0, (b)
0.125, (c) 0.800, and (d) 2.000, respectively. Reprinted with
permission from Ref. 26. See also Color Insert.
Similarly, water-soluble, biofunctional, luminescent mannose-
capped Au NPs (Man-Au NPs) can be prepared through the reaction
of 2.9 nm diameter Au NPs with 11-mercapto-3,6,9-trioxecyl-α--
mannopyranoside (Man-RSH). 25 The luminescence intensity of these
Man-Au NPs is highly dependent on the concentration of Man-RSH.
The water-soluble Man-Au NPs having the highest quantum yield
(9.4%) luoresced ca. 260,000-fold more strongly than did the
original Au NPs. The differently sized Man-Au NPs prepared using
various Man-RSH concentrations (1-10 mM) all possess an