Fig. 4. Optimized poly(l-lysine)-b-poly(ethylene glycol) surfaces for exclusive DNA adsorption. AFM images taken in solution showing selective DNA adsorption on PLL10-b-PEG113/PLL1000–2000 surfaces. (a) DNA plasmid only. (b) The same area following the addition of 160 nM streptavidin. (c) Percentage background streptavidin coverage at 160 nM for functionalization protocols using different PEG chain lengths, and error bars correspond to the minimum and maximum values as determined from two different areas. (d) A higher resolution image of DNA on the PLL10-b-PEG113/PLL1000–2000 surface. Colour scales (see inset top left) for (a) and (b) are 7 nm, (d) with inset colour scale is 9 nm. Scale bars in (a) and (b) are 500 nm and in (d) 200 nm.
