Catalytic control over supramolecular gel formation

Boekhoven, Job; Poolman, Jos M.; Maity, Chandan; Li, Feng; Mee, Lars van der; Minkenberg, Christophe B.; Mendes, Eduardo; Esch, Jan H. van; Eelkema, Rienk

doi:10.1038/nchem.1617

Cited by 257 publications

(238 citation statements)

References 43 publications

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“…As such, catalysis is used as a form of kinetic control over supramolecular structure formation. 45 At the origin of these differences in macroscopic properties lies a change in the morphology of the network that depends on the rate of network formation. Using microscopy techniques such as confocal laser scanning fluorescence microscopy (CLSM) or scanning electron microscopy (SEM), we observed dense, well connected networks when a catalyst was used during formation, whereas uncatalyzed gels consisted of a much less dense, poorly connected network of bundled fibers ( Figure 5).…”

Section: Kinetic Controlmentioning

confidence: 99%

Catalysis of Supramolecular Hydrogelation

et al. 2016

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CONSPECTUSOne often thinks of catalysts as chemical tools to speed up a reaction, or to have a reaction run under more benign conditions. As such, catalysis has a role to play in the chemical industry and in lab scale synthesis that is not to be underestimated. Still, the role of catalysis in living systems (cells, organisms) is much more extensive, ranging from the formation and breakdown of small molecules and biopolymers, to controlling signal transduction cascades and feedback processes, motility and mechanical action. Such phenomena are only recently starting to receive attention in synthetic materials and chemical systems. 'Smart' soft materials could find many important applications ranging from personalized therapeutics to soft robotics, to name but a few. Until recently, approaches to controlling the properties of such materials were largely dominated by thermodynamics, for instance looking at phase behavior and interaction strength. However, kinetics play a large role in determining the behavior of such soft materials, for instance in the formation of kinetically trapped (metastable) states, or the dynamics of component exchange. As catalysts can change the rate of a chemical reaction, catalysis could be used to control the formation, dynamics and fate of supramolecular structures, when the molecules making up these structures contain chemical bonds whose formation or exchange are susceptible to catalysis. In this Account, we describe our efforts to use synthetic catalysts to control the properties of supramolecular hydrogels. Building on the concept of synthesizing the assembling molecule in the self-assembly medium from non-assembling precursors, we will introduce the use of catalysis to change the kinetics of assembler formation, and thereby the properties of the resulting material. In particular, we will focus on the synthesis of supramolecular hydrogels where the use of a catalyst provides access to gel materials with vastly different appearance and mechanical properties, or controls localized gel formation and the growth of gel objects. As such, catalysis will be applied to create molecular materials that exist outside of chemical equilibrium. In all, using catalysts to control the properties of soft materials constitutes a new avenue for catalysis, far beyond the traditional use in industrial and lab scale synthesis.

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Section: Kinetic Controlmentioning

confidence: 99%

Catalysis of Supramolecular Hydrogelation

et al. 2016

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“…The first example of the use of an alkaline phosphatase to trigger the formation of a hydrogel by the dephosphorylation of 9-fluorenylmethoxycarbonyl (Fmoc)-tyrosine phosphate [18][19][20] preceded several others. [21][22] Hirst et al have shown that the amount of biocatalyst used can direct the self-assembly pathway resulting in (kinetic) control of the supramolecular organization of the final supramolecular structure. 23 They also demonstrated that these kinetically locked gels may be ÔunlockedÕ to access a minimum energy state by performing a heat/cool cycle.…”

Section: -2mentioning

confidence: 99%

Biocatalytic Self-Assembly of Tripeptide Gels and Emulsions

et al. 2017

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This version is available at https://strathprints.strath.ac.uk/60875/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.Biocatalytic self-assembly of tripeptide gels and ABSTRACT. We report on the biocatalytic activation of an (unprotected) self-assembling tripeptide to stabilize oil-in-water emulsions on-demand. This is achieved by conversion of a phosphorylated precursor into a hydrogelator using alkaline phosphatase as the trigger. The rate of conversion, controlled by the amount of enzyme used, is shown to play a key role in dictating the morphology of the nanofibrous networks produced. When these amphiphilic tripeptides are used in biphasic mixtures, nanofibers are shown to self-assemble at the aqueous/organic interface but also throughout the surrounding buffer, thereby stabilizing the oil-in-water droplet dispersions. The use of enzymatic activation of tripeptide emulsions gives rise to enhanced control of the emulsification process since emulsions can be stabilized ondemand by simply adding alkaline phosphatase. In addition, control over the emulsion stabilization can be achieved by taking advantage of the kinetics of de-phosphorylation and consequent formation of different stabilizing nanofibrous networks at the interface and/or at the aqueous environment. This approach can be attractive for various cosmetics, food or biomedical applications since both tunability of tripeptide emulsion stability and on-demand stabilization of emulsions can be achieved.

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“…Now, we wish to exploit the full power of chemical synthesis to construct CRNs tuned by small molecules approaching the tunability and functionality of living systems. Although impressive progress in this direction has been made [20][21][22][23][24][25] , we lack a general methodology based on rational design that integrates the structure of (small) molecules with the tuning of the reaction rates for each step in the network. We require a modular approach using common building blocks and reaction conditions, and the ability to program a functional output of the network.…”

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confidence: 99%