Ray et al. 10.1073/pnas.0407020102.

Supporting Information

Files in this Data Supplement:

Supporting Text
Supporting Figure 6
Supporting Figure 7
Supporting Figure 8
Supporting Figure 9
Supporting Figure 10
Supporting Figure 11
Supporting Figure 12
Supporting Table 2
Supporting Table 3
Supporting Table 4
Supporting Table 5

Supporting Figure 6

Fig. 6. Radioimaging of gel analysis showing that almost 100% of the oligos contain the thiol modification.

Supporting Figure 7

Fig. 7. The various oligomers studied and their notations.

Supporting Figure 8

Fig. 8. Topography as imaged by tapping-mode atomic force microscopy of an atomically flat (111) gold surface and of the same substrate covered with various ss (with a different number of G) and dsDNA oligomers.

Supporting Figure 9

Fig. 9. The x-ray photoelectron spectroscopy spectra.

Supporting Figure 10

Fig. 10. Gel electrophoresis of the DNA oligomer 8G.

Supporting Figure 11

Fig. 11. The electron signal as a function after being exposed to 193-nm radiation for 14 sec, the laser intensity.

Supporting Figure 12

Fig. 12. Electron transmission spectra from pure gold substrate. The intensity shown after dividing by 10.

Table 2. The thickness of different ds and ss monolayers calculated from spectroscopic ellipsometry for incidence angle θ = 70°

Sample	1G³	1G⁵	3G	5G	8G	8C	15A	5C	G₃C
Thickness (± 2 Å), Å	33	31	30	33	32	30	30	32	37

Table 3. Coverage calculated from radioactive labeling for different ssDNA and dsDNA monolayers

Sample	1G	3G	5G	8G	8C	15A	G₃C
Molecules per cm^{2 ´} 10¹³ ± 0.4	1.5	1.8	1.2	1.7	1.9	0.9	1.1

Average number of molecules = 1.4 ± 0.4 ´ 10¹³ molecules per cm².

Table 4. Contact angles for different DNA monolayers

Sample	1G	3G	5G	8G	8C	15A	5C	G₃C
Contact angle (± 3° ), °	32	31	31	32	31	36	31	26*

*The monolayer made from dsDNA could not be washed extensively, because denaturation occurs. Therefore, the salt content on the surface is higher, causing a reduction in the contact angle.

Table 5. Atomic ratios calculated from x-ray photoelectron spectroscopy spectra

Atomic ratio	N/P		O/N		C/P		N/S
Sample	1G	8G	1G	8G	1G	8G	1G	8G
Theoretical	5	5	1.1	1.03	10.4	10.4	37.5	37.5
Experimental (± 10%)	4.8	4.4	1.63	1.63	15.5	14.2	29	31.5