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. 2023 Dec 4;39(50):18410–18423. doi: 10.1021/acs.langmuir.3c02567

Figure 3.

Figure 3

Quantitative tuning of the surface density of two biotinylated proteins of different size (in stagnant solution). (A) Schematic drawing of the surface functionalization: ① SLB formation, ② SAv monolayer formation, and ③ co-adsorption of b-ZZ and biotin. (B) AMD of b-ZZ, AMDb-ZZ, over time determined by SE for a range of cbiotin/cb-zz molar ratios (as indicated). Conditions: cb-zz + cbiotin = 0.625 μM was kept constant, with cb-zz and cbiotin determined according to eq 4 (εstagnant < 0.01); biotin/b-ZZ incubation—10 min, starting from 0.3 min; see Figure S5 for details of steps ① and ②. (C) b-ZZ surface density at saturation, Γb-ZZ,sat, measured by SE as a function of the nominal b-ZZ surface density predicted according to eq 4 from the cbiotin/cb-zz molar ratios and assuming Γas = 2ΓSAv. Error bars along the horizontal axis represent the uncertainty in the concentrations of biotin and b-ZZ when computing Γb-ZZ,sat/Γas and the resolution in ΓSAv. Error bars along the vertical axis (about the size of the symbols) represent temporal noise and confidence intervals when fitting the SE data. Black dashed line is a linear fit through the data with a slope of 0.93 ± 0.02.