Catanionic Coacervate Droplets as a Surfactant‐Based Membrane‐Free Protocell Model

Abstract

We report on the formation of surfactant-based complex catanionic coacervate droplets in mixtures of decanoic acid and cetylpyridinium chloride or cetyltrimethylammonium bromide. We show that coacervation occurs over a broad range of composition, pH, and ionic strength. The catanionic coacervates consist of elongated micelles, sequester a wide range of solutes including water-soluble organic dyes, polysaccharides, proteins, enzymes, and DNA, and can be structurally stabilized by sodium alginate or gelatin-based hydrogelation. These results suggest that catanionic coacervates could be exploited as a novel surfactant-based membrane-free protocell model.

Photoswitchable Phase Separation and Oligonucleotide Trafficking in DNA Coacervate Microdroplets

“…[1,2] They play acrucial role for example in the compaction of polynucleotides and regulation of genetic expression. [7,22,23] Fori nstance,t heir formation and dissolution has been achieved by changes in pH, [5] temperature, [24][25][26] ionic strength, [27,28] and more recently by enzymemediated catalytic activity. [5][6][7] These membrane-free molecularly crowded compartments seques-ter functional biomolecules [5,8] and support enzymatic activity, [9,10] protein folding, [11] RNAc atalysis, [12,13] and cell-free protein expression.…”

“…[14] Polynucleotides have been used as scaffold components to assemble coacervate droplets, [15][16][17][18][19] and selective sequestration of guest polynucleotides has been demonstrated in preformed coacervates. [7,22,23] Fori nstance,t heir formation and dissolution has been achieved by changes in pH, [5] temperature, [24][25][26] ionic strength, [27,28] and more recently by enzymemediated catalytic activity. [7,22,23] Fori nstance,t heir formation and dissolution has been achieved by changes in pH, [5] temperature, [24][25][26] ionic strength, [27,28] and more recently by enzymemediated catalytic activity.…”

Dynamic Synthetic Cells Based on Liquid–Liquid Phase Separation

“…In some cases, the polyelectrolyte pair eventually precipitates to form as olidlike complex, but the parameters influencing the nature of the complexf ormed (liquid or solid) for ag iven polyelectrolyte pair remainu nclear. [39,40] Recent studies in this area have soughtt ou nderstand these factors in greaterd etail by using computational modelling combined with better-defined polyelectrolyte structures, [25] in terms of, for example, polymerl ength dispersity, [26] charge distribution, [27] chirality [28] or base pairing.…”

“…[57,58] The polynucleotide exchange rate between the dropletsa nd their environment appears to be highly system-dependent. [40] The sequestration of proteins in membrane-free droplets has also been extensively investigated. [60] The secondary structure [61] and length [62] of RNA, as well as the length and single-versus double-stranded nature of DNA, [63] were reported to affect their partitioning;i n the latter case this was attributed to ac haracteristicm esh size of the coacervate matrix, resulting in the exclusion of longer and stiffer dsDNAc hains.…”

“…[40] Much work remains to ChemBioChem 2019ChemBioChem , 20,2553ChemBioChem -2568 www.chembiochem.org 2019 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim be done, but this study demonstrates that reversible coacervate-to-vesicle transformations could be used to promote spontaneous transfer of DNA from membrane-freet om embrane-bound compartments, andu ltimately to sustain genetic information replication through substrate uptake and waste disposal. [40] Much work remains to ChemBioChem 2019ChemBioChem , 20,2553ChemBioChem -2568 www.chembiochem.org 2019 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim be done, but this study demonstrates that reversible coacervate-to-vesicle transformations could be used to promote spontaneous transfer of DNA from membrane-freet om embrane-bound compartments, andu ltimately to sustain genetic information replication through substrate uptake and waste disposal.…”