Rational Design of Heat‐Set and Specific‐Ion‐Responsive Supramolecular Hydrogels Based on the Hofmeister Effect

Nebot, Vicent J.; Ojeda‐Flores, Juan J.; Smets, Johan; Fernández-Prieto, Susana; Escuder, Beatriu; Miravet, Juan F.

doi:10.1002/chem.201402547

Cited by 54 publications

(38 citation statements)

References 61 publications

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“…Furthermore, the efficiency of the anions in promoting self‐assembly was in good agreement with the Hofmeister series . In another example, molecular hydrogels were prepared from a bolaamphiphilic l ‐valine derivative ( 5 ) in aqueous solutions of different salts . The hydrogels were found to respond selectively to different ions and were either reinforced or weakened by the presence of salts.…”

Section: Peptide‐based Molecular Gelssupporting

confidence: 59%

Peptide‐Based Molecular Hydrogels as Supramolecular Protein Mimics

Singh

Kumar

Miravet

et al. 2016

Chemistry A European J

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158

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Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.

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Section: Peptide‐based Molecular Gelssupporting

confidence: 59%

Peptide‐Based Molecular Hydrogels as Supramolecular Protein Mimics

Singh

Kumar

Miravet

et al. 2016

Chemistry A European J

Self Cite

158

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“…[ c] Enantiomer ratios were determined by chiral HPLC. [19] as the phosphate ion belongs to the group of ions that usually lower the solubility of hydrophobic solutes in water,t ermed kosmotropic ions. [20] For the studied case, this effect is strongly active for both compounds 2 and 4.I ndeed, the 1 HNMR spectra of the two compounds in buffer at pH 7d id not showa ny signal correspondingt of ree compounds, revealing that the soluble fraction of both falls below the detection limit of this technique (< 5%), and therefore > 95 %o ft he catalyst molecules are in the non-protonated active form at that pH (the Supporting Information, Figures S17 and S18).…”

Section: Mechanistic Studiesmentioning

confidence: 99%

Emergent Catalytic Behavior of Self‐Assembled Low Molecular Weight Peptide‐Based Aggregates and Hydrogels

Tena‐Solsona

Nanda

Díaz‐Oltra

et al. 2016

Chemistry A European J

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119

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We report a series of short peptides possessing the sequence (FE)n or (EF)n and bearing l-proline at their N-terminus that self-assemble into high aspect ratio aggregates and hydrogels. We show that these aggregates are able to catalyze the aldol reaction, whereas non-aggregated analogues are catalytically inactive. We have undertaken an analysis of the results, considering the accessibility of catalytic sites, pKa value shifts, and the presence of hydrophobic pockets. We conclude that the presence of hydrophobic regions is indeed relevant for substrate solubilization, but that the active site accessibility is the key factor for the observed differences in reaction rates. The results presented here provide an example of the emergence of a new chemical property caused by self-assembly, and support the relevant role played by self-assembled peptides in prebiotic scenarios. In this sense, the reported systems can be seen as primitive aldolase I mimics, and have been successfully tested for the synthesis of simple carbohydrate precursors.

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“…The large morphological and volume change at the LCST of PNIPAM‐based gels make mechanical studies meaningless. A series of studies on the Hofmeister effect on supramolecular hydrogels showed a dependence of the mechanical properties, but this was merely induced by the hugely different morphologies found for the different assembly conditions of the gels …”

Section: Introductionmentioning

confidence: 99%

Tuning Hydrogel Mechanics Using the Hofmeister Effect

Jaspers

Rowan

Kouwer

2015

Adv Funct Materials

113

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6503wileyonlinelibrary.com mechanical properties. The large morphological and volume change at the LCST of PNIPAM-based gels [ 10 ] make mechanical studies meaningless. A series of studies on the Hofmeister effect on supramolecular hydrogels showed a dependence of the mechanical properties, but this was merely induced by the hugely different morphologies found for the different assembly conditions of the gels. [11][12][13] Here, we describe for the fi rst time that we can use the Hofmeister effect to controllably manipulate the mechanical properties of polymer hydrogels. As expected, the addition of salts directly affects the gelation temperature and, for our thermoresponsive hydrogel, this changes the stiffness of the gel over two orders of magnitude at a constant temperature, for instance 37 °C. We construct hydrogels that range from very soft to stiff, but all at identical concentration. To achieve such change in mechanical response, one commonly needs to vary parameters such as concentration, morphology and bundle (or fi ber) diameter and stiffness. [ 14 ] Some of these are diffi cult to control, while others simultaneously change many important network characteristics; for instance, the concentration changes the biomedically relevant pore size and stiffness of the gel (as well as nonlinear gel properties). The salts, however, are able to shift the mechanics, without changing porosity and network morphology.The polymers we use are ethylene glycol-functionalized polyisocyanides (PICs, Figure 1 b), which form a thermoreversible gel upon heating when dissolved in water. [ 15 ] At the LCST, the polymers become hydrophobic and form a network of entangled semi-fl exible bundles of polymer chains. The mechanical properties of the PIC hydrogels mimic those of biological gels, [ 15 ] including the nonlinear mechanics at large stress (or strain), which is markedly different than that of other synthetic hydrogels. The mechanics of PIC hydrogels is readily tuned by changing concentration, temperature, and polymer length. [ 16 ] Here, we add two additional parameters to this list: the nature of the salt (more precisely the anion) and its concentration.For a long time, the molecular basis of the Hofmeister series was related to the effect of ions on the bulk structure of water. [ 17 ] More recently, however, it was shown that salts generally do not affect the bulk water structure. [ 18,19 ] Instead, more recent theories hypothesize that direct interactions between ions and macromolecules and their fi rst hydration shell can explain the effects fi rst described by Hofmeister. [ 7,[20][21][22][23] The Hofmeister effect is usually more pronounced for anions than for cations and some ions have a stronger effect than others. The general order of the anions, termed the Hofmeister series is shown in Figure 1 a. [ 7,24 ] The ions on the The mechanical properties of hydrogels are commonly modifi ed by changing the concentration of the molecular components. This approach, however, does not only change hydrogel mechanics, but also th...

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Rational Design of Heat‐Set and Specific‐Ion‐Responsive Supramolecular Hydrogels Based on the Hofmeister Effect

Cited by 54 publications

References 61 publications

Peptide‐Based Molecular Hydrogels as Supramolecular Protein Mimics

Peptide‐Based Molecular Hydrogels as Supramolecular Protein Mimics

Emergent Catalytic Behavior of Self‐Assembled Low Molecular Weight Peptide‐Based Aggregates and Hydrogels

Tuning Hydrogel Mechanics Using the Hofmeister Effect

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