Table 1. Bulk and Local RGD Peptide Density of Mixed and Hybrid SAMs and Composition of the Incubation Formulations Used to Prepare Them.
| Platform | Sample | Incubation solution compositiona (mol %) | Incubation solution conc.b (μM) | Estimated maximum bulk average surface RGD densityc (RGD units/nm2) | Estimated maximum local average surface RGD densityd (RGD units/nm2) |
|---|---|---|---|---|---|
| Mixed SAM RGD | SAM PEG 100% | 100% PEG130-SH | 1000 | 0 | 0 |
| SAM RGD 100% | 100% RGD-PEG260-SH | 1000 | 1.22 | 1.22 | |
| SAM RGD 10% | 10% RGD-PEG260-SH | 100 | 0.122 | 0.122 | |
| 90% PEG130-SH | 900 | ||||
| SAM RGD 1% | 1% RGD-PEG260-SH | 10 | 0.0122 | 0.0122 | |
| 99% PEG130-SH | 990 | ||||
| Hybrid SAM RGD-QS | SAM BLANK-QS 100% | 100% QS-PEG3000-SH | 0.022 | 0 | 0 |
| SAM RGD-QS 100% | 100% RGD-QS-PEG3000-SH | 0.022 | 0.078 | 0.078 | |
| SAM RGD-QS 10% | 10% RGD-QS-PEG3000-SH | 0.022 | ∼0.0078–0.078 | 0.078 | |
| 90% PEG130-SH | 0.2 | ||||
| SAM RGD-QS 1.5% | 1.5% RGD-QS-PEG3000-SH | 0.027 | ∼0.0012–0.078 | 0.078 | |
| 98.5% PEG130-SH | 1.8 | ||||
| SAM RGD-QS 0.125% | 0.125% RGD-QS-PEG3000-SH | 0.025 | ∼0.0001–0.078 | 0.078 | |
| 99.875% PEG130-SH | 19.8 |
a
Molar composition in %.
b
Concentration of the components of the solutions in which surfaces were incubated to produce SAMs. QS is considered a supramolecular unit for the calculation of molar concentrations with an approximate molecular weight of 1.86 × 107 ± 0.78 × 107 Da (see the Supporting Information Section 3).
c
Estimated by calculating the packing density of the RGD units on a flat surface.
d
In mixed SAMs, RGD is not localized over QS nanovesicles, and therefore local and bulk density will be the same; in hybrid SAMs, the local density of RGD units is the same as the density of RGD units on the QS surface and will not change with QS dilution on the SAM.