Synthesis of Sequence-Controlled Multiblock Single Chain Nanoparticles by a Stepwise Folding–Chain Extension–Folding Process

The specific activity of proteins can be traced back to their highly defined tertiary structure, which is a result of a perfectly controlled intrachain folding process. In the herein presented work the folding of different distinct domains within a single macromolecule is demonstrated. RAFT polymerization was used to produce multiblock copolymers, which are decorated with pendant hydroxyl groups in foldable sections, separated by nonfunctional spacer blocks in between. OH-bearing blocks were folded using an isocyanate cross-linker prior to chain extension to form single chain nanoparticles (SCNP). After addition of a spacer block and a further OH decorated block, folding was repeated to generate individual SCNP within a polymer chain. Control experiments were performed indicating the absence of interblock cross-linking. SCNP were found to be condensed by a combination of covalent and supramolecular (hydrogen bonds) linkage. The approach was used to create a highly complex pentablock copolymer having three...