Table 2.
XPS results for LKα14 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 |
|---|---|---|---|---|---|---|
| 0.0002 | 82.1 (1.1) | 13.3 (0.2) | 1.9 (0.5) | 2.8 (0.2) | 43.9 (0.9) | 0.024 (0.006) |
| 0.0005 | 79.1 (5.6) | 13.9 (1.2) | 4.9 (1.9) | 2.0 (0.3) | 36.1 (5.2) | 0.094 (0.050) |
| 0.001 | 77.6(0.7) | 12.9(0.5) | 7.9 (0.6) | 1.6 (0.1) | 29.0 (1.2) | 0.19 (0.02) |
| 0.002 | 76.2 (2.1) | 13.7 (0.2) | 8.7 (0.5) | 1.4 (0.1) | 26.9 (1.9) | 0.24 (0.03) |
| 0.005 | 75.1 (2.2) | 14.0 (0.3) | 9.6 (0.5) | 1.3 (0.1) | 26.5 (2.1) | 0.27 (0.03) |
| 0.01 | 75.1 (1.3) | 13.8 (0.4) | 9.8 (0.5) | 1.3 (0.1) | 25.3 (1.4) | 0.29 (0.03) |
| 0.05 | 75.8 (1.2) | 13.3 (0.6) | 9.6 (0.5) | 1.3 (0.3) | 23.9 (0.6) | 0.32 (0.03) |
| 1 | 74.6 (1.1) | 14.2 (0.5) | 10.4 (0.5) | 0.8 (0.1) | 19.1 (1.6) | 0.44 (0.06) |
| Calculated Values for Monolayer | 76.3 | 13.7 | 8.0 | 2.0 | 29.9 | 0.19 |
| Calculated Values for Bilayer | 74.8 | 12.7 | 11.4 | 1.1 | 19.7 | 0.46 |
*
Renormalized to 100% without the Au signal.