Supramolecular Structures Generated by Spherical Polyelectrolyte Brushes and their Application in Catalysis

Lü, Yan; Wittemann, Alexander; Ballauff, Matthias

doi:10.1002/marc.200800789

Cited by 82 publications

(67 citation statements)

References 67 publications

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“…This force already discussed above for the interaction of proteins with single chains of polyelectrolytes will be even stronger due to the nearly 100% confinement of the ions within the brush layer. 27,48,90,93,133 iii)…”

Section: Ii)mentioning

confidence: 99%

Interaction of Proteins with Polyelectrolytes: Comparison of Theory to Experiment

et al. 2018

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We discuss recent investigations of the interaction of polyelectrolytes with proteins. In particular, we review our recent studies on the interaction of simple proteins such as human serum albumin (HSA) and lysozyme with linear polyelectrolytes, charged dendrimers, charged networks, and polyelectrolyte brushes. In all cases discussed here, we combined experimental work with molecular dynamics (MD) simulations and mean-field theories. In particular, isothermal titration calorimetry (ITC) has been employed to obtain the respective binding constants K and the Gibbs free energy of binding. MD simulations with explicit counterions but implicit water demonstrate that counterion release is the main driving force for the binding of proteins to strongly charged polyelectrolytes: patches of positive charges located on the surface of the protein become multivalent counterions of the polyelectrolyte, thereby releasing a number of counterions condensed on the polyelectrolyte. The binding Gibbs free energy due to counterion release is predicted to scale with the logarithm of the salt concentration in the system, which is verified by both simulations and experiment. In several cases, namely, for the interaction of proteins with linear polyelectrolytes and highly charged hydrophilic dendrimers, the binding constant could be calculated from simulations to very good approximation. This finding demonstrated that in these cases explicit hydration effects do not contribute to the Gibbs free energy of binding. The Gibbs free energy can also be used to predict the kinetics of protein uptake by microgels for a given system by applying dynamic density functional theory. The entire discussion demonstrates that the direct comparison of theory with experiments can lead to a full understanding of the interaction of proteins with charged polymers. Possible implications for applications, such as drug design, are discussed.

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Section: Ii)mentioning

confidence: 99%

Interaction of Proteins with Polyelectrolytes: Comparison of Theory to Experiment

et al. 2018

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“…[1][2][3] This responsiveness makes them attractive for applications in biomedicine, 4 drug delivery, [5][6][7] catalysis, [8][9][10] sensing, [11][12][13][14] and photonics. 15,16 The most prominent material exhibiting environmental sensitivity is poly(N-isopropylacrylamide) (pNIPAAm).…”

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confidence: 96%

Critical fluctuations and static inhomogeneities in polymer gel volume phase transitions

Habicht

Schmolke

Goerigk

et al. 2015

J Polym Sci B Polym Phys

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Thermoresponsive polymer gels exhibit pronounced swelling and deswelling upon changes in temperature, accompanied by dynamic concentration fluctuations that have been interpreted as critical opalescence. These fluctuations span lengthscales similar to that of static structures in the gels, such as the gel polymer-network meshsize (1-10 nm) and static polymer-network crosslinking inhomogeneities (10-1000 nm). To systematically investigate this overlay, we use droplet-based microfluidics and fabricate submillimeter-sized gel particles with varying static heterogeneity, as revealed on a molecular scale by proton NMR. When these microgels are probed by small-angle neutron scattering, the detection of dynamic fluctuations during the volume phase transitions is strongly perturbed by the co-existing static inhomogeneity. Depending of the type of data analysis employed, the temperature-dependent evolution of the correlation length associated to the dynamic fluctuations does or does not agree with predictions by the critical scaling theory. Only the most homogeneous sample of this study, prepared by controlled polymer crosslinking in droplet microfluidics, shows a diverging correlation length in agreement to the critical scaling theory independent of the specific approach of data analysis. These findings suggest that care must be taken about polymernetwork heterogeneity when gel volume phase transitions are evaluated as critical phenomena.

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“…More interestingly, these features are tunable due to the stimuli-responsive behaviour of the microgel particles [38]. Thus, these hybrid particles exhibit a combination of "inorganic" and "organic" characteristics [39,40].…”

Section: Immobilization Of Metal Nanoparticles In Microgelsmentioning

confidence: 97%

Core-Shell Microgels as Nanoreactors

Lü

Welsch

Dzubiella

et al. 2013

Intelligent Hydrogels

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Core-shell microgel particles consisting of a solid core and a shell of crosslinked PNIPA network present model systems of high interest. Here we review our recent work on the core-shell microgel particles and their application as nanoreactors for the immobilization of catalytic active metal nanoparticles or enzymes. The catalytic activity of nanoparticles can be modulated both by the volume transition and the change of polarity of the thermosensitive shell of the carrier system. Special emphasis is put on recent work on the kinetic analysis of protein adsorption onto microgel particles, which was complemented with the thermodynamic study done by ITC. All results herein demonstrate that core-shell microgel particles may serve as "active" nanoreactor for catalytically active nanostructures, namely for metal nanoparticles and enzymes.

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Supramolecular Structures Generated by Spherical Polyelectrolyte Brushes and their Application in Catalysis

Cited by 82 publications

References 67 publications

Interaction of Proteins with Polyelectrolytes: Comparison of Theory to Experiment

Interaction of Proteins with Polyelectrolytes: Comparison of Theory to Experiment

Critical fluctuations and static inhomogeneities in polymer gel volume phase transitions

Core-Shell Microgels as Nanoreactors

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