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

Abstract

Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://pubs.acs.org/page/policy/articlesonrequest/index.html ." A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL above for details on accessing the published version and note that access may require a subscription. ABSTRACTThe specific activity of proteins can be traced back to their highly defined tertiary structure, which is a result of a perfectly controlled intra-chain 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 multi-block copolymers, which are decorated with pendant hydroxyl groups in foldable sections, separated by non-functional 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 inter block cross linking. SCNP were found to be condensed by a combination of covalent and supra molecular (hydrogen bonds) linkage. The approach was used to create a highly complex penta-block copolymer having three individually folded subdomains with an overall dispersity of 1.21. The successful formation of SCNP was confirmed by size exclusion chromatography (SEC), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC) and atomic force microscopy (AFM).

Stepwise Light‐Induced Dual Compaction of Single‐Chain Nanoparticles

“…In all performed experiments, a Δ M p of 23% for the first major shift and, for the second, small shift, a Δ M p of 5% is reproducibly observed (duplicate experiments) and in good agreement with values reported in the literature. [6b,7] To eliminate SEC measurement errors, all samples were measured directly after one another to maintain exactly the same elution conditions.…”

“…This can be achieved either by pure chemical orthogonality or through a protecting group approach. [5a,6] Alternatively, successive sequences of growth and folding steps can be employed . We recently introduced two photoreactive methacrylic monomers, which were incorporated into 3D microstructures, thereby imparting dual surface photoreactivity to the latter .…”

Tacticity dependence of single chain polymer folding

“…[3][4][5] Upon a specific stimulus, the for-mation of bonds between these crosslinking entities over extended distances along the backbone transforms the macromolecules into compact conformations. [6][7][8] In analogy to biological systems, we refer to these structures in the following as 'folded' conformations. In these distinct conformations, the SCNP may perform specific functions, such as sensing or catalysis, and even enable applications in nanomedicine.…”

Metal‐Folded Single‐Chain Nanoparticle: Nanoclusters and Self‐Assembled Reduction‐Responsive Sub‐5‐nm Discrete Subdomains

“…In this sense, self‐assembly of SCNPs into ultrafine heterogeneous discrete subdomains may give a superstructure analogous to protein's tertiary structure . Compartmentalization of SCNPs can be fulfilled by orthogonal covalent crosslinking as reported by Lutz and Perrier, or orthogonal hydrogen bonding as demonstrated by Palmans, Barner‐Kowollik, Meijer, and coworkers . In contrast, assembly of SCNPs into hierarchical nanomaterials is less understood.…”