Dynamic actuation of glassy polymersomes through isomerization of a single azobenzene unit at the block copolymer interface

Abstract

Nature has engineered exquisitely responsive systems where molecular-scale information is transferred across an interface and propagated over long length scales. Such systems rely on multiple interacting, signalling and adaptable molecular and supramolecular networks that are built on dynamic, non-equilibrium structures. Comparable synthetic systems are still in their infancy. Here, we demonstrate that the light-induced actuation of a molecularly thin interfacial layer, assembled from a hydrophilic-azobenzene-hydrophobic diblock copolymer, can result in a reversible, long-lived perturbation of a robust glassy membrane across a range of over 500 chemical bonds. We show that the out-of-equilibrium actuation is caused by the photochemical trans–cis isomerization of the azo group, a single chemical functionality, in the middle of the interfacial layer. The principles proposed here are implemented in water-dispersed nanocapsules, and have implications for on-demand release of embedded cargo molecules.

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Fig. 1: Structure and self-assembly of block copolymer P2.
Fig. 2: Encapsulation ability and stimuli-responsive behaviour of P2 vesicles.
Fig. 3: P2 vesicles demonstrating non-equilibrium behaviour.
Fig. 4: Mechanistic investigations of the non-equilibrium behavior of the assembly.

Change history

  • 28 June 2018

    In the version of this Article originally published, multiple changes to the “Results and discussion” section were required. In paragraph 1, “(Supplementary Fig. 1)” should have read “(Fig. 1e–j and Supplementary Fig. 1)”; in the first sentence of paragraph 3, “(R6G)” should have read “(R6G, Fig. 2i)”; in paragraph 6 in the sentence beginning “Temporal release of hydrophilic...”, Supplementary Fig. 4 should have been cited after “360 nm”; in paragraph 9, in the sentence beginning “To test this...”, “Fig. 4e” should have read “Fig. 4a”; in paragraph 10, in the sentence beginning “When the irradiation...”, “(Fig. 4a–d)” should have read “(Fig. 4d,e)”; in paragraph 11, in the sentence beginning “Pristine PLA”, “P1” should have read “P2”; and in the penultimate paragraph, in the sentence beginning “Moreover, a control PEG-PLA...”, “block copolymer” should have been followed by (P5); Fig. 4g should have been Fig. 4c; “hydrophobic azobenzene small molecules” should have been followed by (12); and Fig. 4f should have been Fig. 4b. Finally, Supplementary Videos 1 and 2 were missing from the Article. All of these corrections have been made to the online versions.

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Acknowledgements

The authors thank the US Army Research Office for funding through the MURI program (W911NF-15-1-0568).

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Authors

Contributions

S.T. conceived and supervised the project. M.R.M. initiated the project. M.R.M. and P.R. performed all the experiments, with help from S.S. J.d.P. initiated the simulations and computational studies. L.A. performed all the simulation studies. All authors contributed to the discussion of the results and preparation of the manuscript.

Corresponding author

Correspondence to S. Thayumanavan.

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Supplementary information

Supplementary information

Supplementary synthesis and characterization details and analysis, Schemes 1–3, and Figures 1–16

Supplementary Movie 1

Real-time movie showing that no reaction occurred between hexamathylene diamine encapsulated within the aqueous lumen of the supramolecular capsule formed by P2 and sebacoyl chloride dissolved in hexane.

Supplementary Movie 2

Real-time movie of nylon formation between hexamathylene released from the supramolecular capsule formed by P2 upon light irradiation and sebacoyl chloride dissolved in hexane.

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Molla, M.R., Rangadurai, P., Antony, L. et al. Dynamic actuation of glassy polymersomes through isomerization of a single azobenzene unit at the block copolymer interface. Nature Chem 10, 659–666 (2018). https://doi.org/10.1038/s41557-018-0027-6

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