Grafting-through approach moieties

The third route follows the grafting-through approach in which various protein reactive groups are incorporated within a growing polymer chain by using monomers that can react either directly or after polymerization via the introduced reactive moieties with peptides or proteins [69], Noteworthy, this third approach does not necessarily result only in conjugation of one protein/peptide to a polymer chain, but also in conjugation of several protein/peptide to a polymer chain. 

In order to utilize the grafting-through approach, the substrate first needs to be modified with a polymerizable monomer unit, thus becoming a hybrid macromonomer. The macromonomer is then copolymerized with low molecular weight monomers to form a polymer chain with sewed substrate moieties. This method is illustrated in Scheme 7. 

A grafting-from approach is also possible by introducing an amino acid bearing an ATRP initiator moiety [165]. In this approach the non-natural amino acid was incorporated through translational transformation. As ATRP initiator, 2-bromo-isobutyric acid was used, which was attached to the 4-aminophenylalanine. 

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