Phase Diagram of Coacervate Complexes Containing Reversible Coordination Structures

Wang, Junyou; Stuart, Martien A. Cohen; Gucht, Jasper van der

doi:10.1021/ma301690t

Cited by 30 publications

(28 citation statements)

References 32 publications

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“…Presumably, the unequal partitioning of nucleotides and pLys into the coacervate droplets still results in charge neutrality. 27,30,32 The observed shift of the onset of coacervation simply reflects the strong asymmetry between the interacting species: pLys is a long polyelectrolyte, whereas nucleotides bear resemblance to small ions. As a consequence, the concentration of ADP (and ATP) in the solution that coexists with the coacervate is significant, whereas the pLys concentration in solution is low.…”

Section: Phase Diagrams Of Adp and Atp Coacervatesmentioning

confidence: 99%

“…As a consequence, the concentration of ADP (and ATP) in the solution that coexists with the coacervate is significant, whereas the pLys concentration in solution is low. 27,32 The fact that the shift is more extreme for ADP than ATP suggests that ATP partitions more strongly into pLys coacervates. From plots of the turbidity as a function of added salt ( Fig.…”

Section: Phase Diagrams Of Adp and Atp Coacervatesmentioning

confidence: 99%

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Reversible generation of coacervate droplets in an enzymatic network

Nakashima¹,

Baaij²,

Spruijt³

2018

Soft Matter

167

190

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Cells can control the assembly and disassembly of membraneless organelles by enzymatic processes, but similar control has not been achieved in vitro yet. Here we develop ATP-based coacervate droplets as artificial membraneless organelles that can be fully controlled by two cooperating enzymes. Droplets can be generated within a minute following the addition of phosphoenolpyruvate as a substrate, and they can be dissolved within tens of seconds by adding glucose as the second substrate. We show how the rates of droplet generation and dissolution can be tuned by varying the enzyme and substrate concentrations, and we support our findings with a kinetic model of the underlying enzymatic reaction network. As all steps of the coacervate droplet life cycle, including nucleation, coarsening, and dissolution, occur under the same reaction conditions, the cycle can be repeated multiple times. In addition, by carefully balancing the rates of both enzymatic reactions, our system can be programmed to either form or dissolve droplets at specified times, acting as a chemical timer.

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Section: Phase Diagrams Of Adp and Atp Coacervatesmentioning

confidence: 99%

Section: Phase Diagrams Of Adp and Atp Coacervatesmentioning

confidence: 99%

Reversible generation of coacervate droplets in an enzymatic network

Nakashima¹,

Baaij²,

Spruijt³

2018

Soft Matter

167

190

View full text Add to dashboard Cite

show abstract

“…Experimentally, asymmetry in one or more of these parameters is nearly unavoidable. 22,[38][39][40][41][42][43][44][45] However, apart from a few theoretical or simulation studies 20,28,37,[46][47][48][49][50] that have examined some specific asymmetry effects in these parameters, a comprehensive picture of how asymmetry affects the phase behavior is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte complex coacervation: Effects of concentration asymmetry

Zhang

Alsaifi

et al. 2018

The Journal of Chemical Physics

158

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Using a simple liquid-state theory, we study the phase behaviors of concentration-asymmetric mixtures of polycation and polyanion solutions. We construct a three-dimensional (3D) phase diagram in terms of the concentrations of the three independent charged components: polycation, polyanion, and small cation (ρ p+ −ρ p− −ρ +), for a given Bjerrum length. This phase diagram yields rich and complex phase-separation scenarios. To illustrate, we sequentially examine the following three systems that are directly relevant to experiments: a symmetric mixture, an asymmetric mixture with one type of small ions, and an asymmetric mixture with both types of small ions. We re-express the information in the 3D phase diagram using three experimentally more easily controllable parameters-the asymmetry factor r, the initial extra-salt concentration ρ s,0 , and the initial polyelectrolyte (PE) concentration ρ p,0 of both solutions prior to mixing. We construct three reduced phase diagrams in the ρ p,0 −r, r−ρ s,0 , and ρ s,0 −ρ p,0 planes, respectively, and examine the evolution of the volume fraction of the coexisting phases, concentration of the PE and small-ion species in each phase, and the Galvani potential Ψ G , as functions of these experimental controlling parameters. We rationalize our findings in terms of the key thermodynamic factors, namely, the translational entropy of the small ions, the electrostatic correlation energy, and the requirement for charge neutrality.

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“…Oparin's hypothesis has however been dismissed in modern theories of the origin of life, particularly after the discovery of DNA as the genetic material [7]. Most of the earlier studies on polyelectrolyte complexation focused on coacervation of natural polymers such as albumin and gelatin, but recent studies [2,3,[8][9][10][11][12] have extended this to the complexation of synthetic polyelectrolytes. Renewed scientific interest in polyelectrolyte complexation is due, in part, to its use in polyelectrolyte assemblies and multilayer films [13,14], which have many technological applications [15,16].…”

Section: Introductionmentioning

confidence: 99%

pH and Salt Effects on the Associative Phase Separation of Oppositely Charged Polyelectrolytes

et al. 2014

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Abstract:The classical Voorn-Overbeek thermodynamic theory of complexation and phase separation of oppositely charged polyelectrolytes is generalized to account for the charge accessibility and hydrophobicity of polyions, size of salt ions, and pH variations. Theoretical predictions of the effects of pH and salt concentration are compared with published experimental data and experiments we performed, on systems containing poly(acrylic acid) (PAA) as the polyacid and poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) or poly(diallyldimethyl ammonium chloride) (PDADMAC) as the polybase. In general, the critical salt concentration below which the mixture phase separates, increases with degree of ionization and with the hydrophobicity of polyelectrolytes. We find experimentally that as the pH is decreased below 7, and PAA monomers are neutralized, the critical salt concentration increases, while the reverse occurs when pH is raised above 7. We predict this asymmetry theoretically by introducing a large positive Flory parameter (= 0.75) for the interaction of neutral PAA monomers with water. This large positive Flory parameter is supported by molecular dynamics simulations, which show much weaker hydrogen bonding between neutral PAA and water than between charged PAA and water, while neutral and charged PDMAEMA show similar numbers of hydrogen bonds. This increased hydrophobicity of neutral PAA at reduced pH increases the tendency towards phase separation despite the reduction in charge interactions between the polyelectrolytes. Water content and volume of coacervate are found to be a strong function of the pH and salt concentration.

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Phase Diagram of Coacervate Complexes Containing Reversible Coordination Structures

Cited by 30 publications

References 32 publications

Reversible generation of coacervate droplets in an enzymatic network

Reversible generation of coacervate droplets in an enzymatic network

Polyelectrolyte complex coacervation: Effects of concentration asymmetry

pH and Salt Effects on the Associative Phase Separation of Oppositely Charged Polyelectrolytes

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