Table 4.
XPS results for LKβ15 adsorption onto carboxyl SAMs. The C, O, N, and S atomic percents were renormalized to 100 atomic % to show the composition of the organic overlayer (SAM plus peptide). The Au atomic % before renormalization and the N/Au ratio show the attenuation of the gold signal by the organic overlayer.
| Peptide Adsorption Concentration mg/mL | C atomic %* | O atomic %* | N atomic %* | S atomic %* | Au atomic % | N/Au ratio |
|---|---|---|---|---|---|---|
| 0.0005 | 80.7 (1.0) | 13.6 (0.5) | 3.4 (0.7) | 2.4 (0.3) | 37.7 (3.7) | 0.057 (0.016) |
| 0.001 | 77.6 (1.2) | 14.3 (0.9) | 6.4 (1.0) | 1.7 (0.5) | 34.2 (1.4) | 0.12 (0.02) |
| 0.003 | 74.7 (0.3) | 13.7 (0.2) | 10.5 (0.2) | 1.0 (0.1) | 21.9 (0.6) | 0.38 (0.02) |
| 0.005 | 75.3 (0.7) | 13.3 (0.3) | 10.2 (0.4) | 1.3 (0.1) | 22.2 (0.8) | 0.36 (0.03) |
| 0.01 | 74.3 (0.2) | 13.5 (0.1) | 11.2 (0.2) | 1.0 (0.0) | 19.1 (0.2) | 0.47 (0.01) |
| 0.05 | 74.1 (0.5) | 13.8 (0.3) | 11.0 (0.3) | 1.0 (0.1) | 19.3 (0.9) | 0.46 (0.03) |
| 0.3 | 71.3 (0.5) | 15.1 (0.4) | 13.1 (0.1) | 0.5 (0.1) | 8.5 (0.9) | 1.43 (0.16) |
| Calculated Values for Monolayer | 76.2 | 13.7 | 8.2 | 2.0 | 30.0 | 0.19 |
| Calculated Values for Bilayer | 74.6 | 12.7 | 11.7 | 1.1 | 19.7 | 0.48 |
*
Renormalized to 100% without the Au signal.