Figure 3. Covalent attachment techniques for surface bio-functionalization.

A) Hydroxyl-terminated POEGMA brushes are activated with DSC. The brushes are then functionalized with streptavidin (red symbol) and then a biotinylated (green symbol) Ab for biosensing. B) Abs are contact printed onto a POEGMA-co-PGMA block copolymer brush, resulting in covalent attachment of the Abs to the epoxide groups under mild conditions. Subsequently, the remaining epoxide groups are inactivated. C) Carboxylic acid groups from PCBAA brushes are reacted with NHS/EDC to yield a reactive NHS-ester, followed by functionalization with an Ab via the formation of an amide bond. Subsequently, the surface is inactivated and reverts to a non-fouling state.