The orthogonal, stepwise, and order-independent unfolding of single-chain nanoparticles (SCNPs) is introduced as a key step towards actively controlling the folding dynamics of SCNPs. The SCNPs are compacted by multiple hydrogen bonds and host–guest interactions. Well-defined diblock (AB) and tetrablock (ABCD) copolymers are equipped with orthogonal recognition motifs via modular ligation along the lateral chain. Initially, single-chain folding of the diblock copolymer was induced by the host–guest complexation of benzo-21-crown-7 (B21C7, host) and a secondary ammonium salt (AS, guest), representing an efficient avenue for single-chain collapse. Next, both orthogonal Hamilton wedge (HW) and cyanuric acid (CA) as well as B21C7–AS motifs were employed to generate SCNPs based on the ABCD polymer system. Subsequently, the stepwise dual-gated and order-independent unfolding of the SCNPs was investigated by the addition of external stimuli. The folding and unfolding were explored by 1D1H NMR spectroscopy, dynamic light scattering (DLS), and diffusion-ordered NMR spectroscopy (DOSY).
Bibliographical noteFunding Information:
C.B.-K. and B.L. acknowledge funding for this project by the Sonderforschungsbereich 1176, project A1, of the German Research Council (DFG). C.B.-K. and B.L. also acknowledge long-term funding by the Helmholtz Association in the context of the Biointerfaces in Technology and Medicine (BIFTM) program. NMR measurements were performed in the DFG instrumentation facility Pro
- host–guest interactions
- orthogonal unfolding
- polymer synthesis
- single-chain folding
- supramolecular chemistry