Team:TU Eindhoven/Background/SPAAC Reaction

SPAAC Reaction: Bio-Orthogonal Click Chemistry

In order to functionalize bacterial membranes with polymers, two strategies can be followed: one can either engineer the bacteria in such a way that they produce the entire polymer, this strategy is further discussed under Zwitterionic Antifouling Protein, or only produce an ‘anchor’ on which polymers can be reacted. The latter strategy requires so-called bio-orthogonal chemistry; chemistry in which the two components are non-interacting (orthogonal) to the functionality presented in biological systems. Furthermore, the reaction conditions have to be viable for cells; in water, at (near-) neutral pH, at temperatures ranging from 25 to 37°C and without any cytotoxic reagents or by-products. (Baskin & Bertozzi, 2007)

A common functional group used in bio-orthogonal reactions is the azide, which does not exist among or reacts with functional groups in biology and is both kinetically stable and thermodynamically high in energy to specific reactivity. Using the azide functional group, two components can be linked together inherently efficient, therefore those types of reactions are called click reactions. (Baskin & Bertozzi, 2007) Until now, three bio-orthogonal click reactions are known: