Nanopropulsion by Biocatalytic Self-Assembly

Leckie, Joy; Hope, AB; Hughes, Michael; Debnath, Sisir; Fleming, Scott W.; Wark, Alastair W.; Ulijn, Rein V.; Haw, Mark

doi:10.1021/nn503875y

Cited by 17 publications

(15 citation statements)

References 71 publications

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“…[13][14][15] Synthetic supramolecular polymers are also being exploited in nanofabrication, for the development of nanowires [16][17][18][19] or as components of artificial molecular machines. 20 For such applications, what is required are molecules that, like their biological counterparts, polymerize and de-polymerize in response to small environmental changes. This behaviour requires that the polymerization is cooperative.…”

Section: Introductionmentioning

confidence: 99%

Modulation of the cooperativity in the assembly of multistranded supramolecular polymers

Campanella

Lopez-Fontal

Milanesi

et al. 2017

Phys. Chem. Chem. Phys.

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It is highly desirable that supramolecular polymers self-assemble following small changes in the environment. The degree of responsiveness depends on the degree of cooperativity at play during the assembly. Undertanding how to modulate and quantify cooperativity is therefore highly desirable for the study and design of responsive polymers. Here we show that the cooperative assembly of a porphyrin-based, double-stranded polymer is triggered by changes in building blocks and in salt concentration. We develop a model that accounts for this responsiveness by assuming the binding of the salt countercations to the double-stranded polymer. Using our assembly model we generate plots that show the increase in concentration of polymer versus the normalized concentration of monomer. These plots are ideally suited to appreciate changes in cooperativity, and show that, for our system, these changes are consistent with the increase in polymer length observed experimentally. Unexpectedly, we find that polymer stability increases when cooperativity decreases. We attribute this behaviour to the fact that increasing salt concentration stabilizes the overall polymer more than the nucleus. In other words, the cooperativity factor , defined as the ratio between the growth constant Kg and the nucleation constant Kn decreases as the overall stability of the polymer increases. Using our model to simulate the data, we generate cooperativity plots to explore changes in cooperativity for multistranded polymers. We find that, for the same pairwise association constants, the cooperativity sharply increases with the number of strands in the polymer. We attribute this dependence to the fact that the larger the number of strands, the larger is the nucleus necessary to trigger polymer growth. We show therefore that the cooperativty factor  does not properly account for the cooperativity behaviour of multistranded polymers, or any supramolecular polymer with a nucleus composed of more than 2 building blocks, and propose the use of the corrected cooperativity factor m. Finally, we show that multistranded polymers display highly cooperative polymerisation with pairwise association constants as low as 10 M -1 between the building blocks, which should simplify the design of responsive supramolecular polymers.

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Section: Introductionmentioning

confidence: 99%

Modulation of the cooperativity in the assembly of multistranded supramolecular polymers

Campanella

Lopez-Fontal

Milanesi

et al. 2017

Phys. Chem. Chem. Phys.

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“…This review mainly focuses on MNMs based on controlled assembled architectures. The collective behaviors and self‐assembly phenomena powered motion of MNMs, although related to the concept of self‐assembly, are beyond the scope of the present report.…”

Section: Introductionmentioning

confidence: 93%

Self‐Propelled Micro‐/Nanomotors Based on Controlled Assembled Architectures

et al. 2015

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Synthetic micro-/nanomotors (MNMs) are capable of performing self-propelled motion in fluids through harvesting different types of energies into mechanical movement, with potential applications in biomedicine and other fields. To address the challenges in these applications, a promising strategy that combines controlled assembly (bottom-up approaches) with top-down approaches for engineering autonomous, multifunctionalized MNMs is under investigation, beginning in 2012. These MNMs, derived from layer-by-layer assembly or molecular self-assembly, display the advantages of: i) mass production, ii) response to the external stimuli, and iii) access to multifunctionality, biocompatibility, and biodegradability. The advance on how to integrate diverse functional components into different architectures based on controlled assemblies, to realize controlled fabrication, motion control (including the movement speed, direction, and state), and biomedical applications of MNMs, directed by the concept of nanoarchitectonics, are highlighted here. The remaining challenges and future research directions are also discussed.

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“…79 Ulijn's group investigated hydrogelation of a tripeptide produced by a chemical reaction between diphenylalanine dipeptide and Fmoc-phenylalanine in the presence of thermolysin. 80 Many enzymes such as b-lactamase, 81 chymotrypsin, 82 b-galactosidase, 83 esterase, 84 glucose oxidase, 85,86 peroxidase 87 phosphatase, 79,88 and thermolysin 80,89 have been explored to trigger and control molecular gelation. Abul-Haija and Ulijn illustrated that dynamic transformation of different nanostructures could be achieved by coassembly of sequence adaptive peptide obtained through dynamic combinatorial chemistry in presence of polysaccharides and thermolysin.…”

Section: (Ii) Enzymatic Reactionmentioning

confidence: 99%