Table 3.
XPS results for LKβ15 adsorption onto methyl 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 |
|---|---|---|---|---|---|---|
| 0.01 | 89.3 (0.4) | 5.2 (0.5) | 3.0 (0.2) | 2.5 (0.2) | 42.2 (0.7) | 0.041 (0.004) |
| 0.05 | 88.9 (1.3) | 5.7 (1.5) | 3.3 (0.4) | 2.1 (0.5) | 42.1 (1.5) | 0.045 (0.005) |
| 0.1 | 81.9 (3.8) | 10.9 (2.4) | 5.8 (1.9) | 1.4 (0.4) | 37.6 (5.2) | 0.11 (0.07) |
| 0.2 | 80.7 (1.3) | 12.2 (0.7) | 6.2 (0.7) | 0.9 (0.2) | 38.2 (2.3) | 0.10 (0.02) |
| 0.3 | 80.1 (3.3) | 11.1 (1.5) | 7.7 (2.1) | 1.2 (0.3) | 33.1 (7.2) | 0.18 (0.09) |
| 0.4 | 78.4 (2.0) | 14.0 (1.3) | 6.7 (1.7) | 0.9 (0.4) | 31.6 (4.6) | 0.15 (0.07) |
| 0.5 | 75.0 (2.6) | 14.2 (0.7) | 10.2 (2.0) | 0.7 (0.2) | 22.2 (7.0) | 0.42 (0.23) |
| Calculated Values for Monolayer | 82.9 | 6.5 | 8.6 | 2.0 | 34.3 | 0.17 |
| Calculated Values for Bilayer | 78.0 | 8.9 | 12.0 | 1.1 | 22.6 | 0.41 |
*
Renormalized to 100% without the Au signal.