Figure 2.

Click reactions on PEG-alkyne modified surfaces with various PEG-alkyne mol % fractions. Determination of the coupled peptide density with different ratios of PEG-alkyne and PEG₂₀₀₀ by enzymatic digestion through α-chymotrypsin. The peptide density is quantified by fluorescence intensity measurements in solution after the release of a formerly surface-bound fluorophore-bearing part of the peptide (filled circles, left y axis, blue). In addition, fluorescence intensities versus the mol % of PEG-alkyne on the surfaces before (filled squares, right y axis, red) and after enzymatic digestion (empty squares, right y axis, red) are illustrated. The error bars are the standard deviations of at least three independent experiments.