Significance Conventional coacervates can form on mixing oppositely charged polyelectrolytes in aqueous solutions, due to electrostatic attraction between the polymers. This report describes first instance (to best of our knowledge) complexation and coacervation two positively by overcoming longer-range repulsion. The molecular force measurements theoretical simulations demonstrate that like-charged coacervate is most likely driven strong cation– π interactions inspired marine mussel...

Adhesive systems in many marine organisms are postulated to form complex coacervates (liquid-liquid phase separation) through a process involving oppositely charged polyelectrolytes. Despite this ubiquitous speculation, most well-characterized mussel adhesive proteins cationic and polyphenolic, the pursuit of negatively required for bulk coacervation formation internally remains elusive. In study, we provide clue unraveling paradox by showing bulky fluid/fluid separation single recombinant...

The first direct probing of the nanomechanics cation–π interactions in aqueous media was accomplished by using a surface forces apparatus with complementary theoretical simulations. tetraethylammonium (TEA) ion breaks adhesion between poly-L-tryptophan (PTrp) and poly-L-lysine (PLL) 100 times higher sensitivity relative to K+ (PS=polystyrene, PTyr=poly-L-tyrosine, ACh=acetylcholine). As service our authors readers, this journal provides supporting information supplied authors. Such materials...

Here we report the possible contribution of cation-π interaction to underwater adhesion mussels by using DOPA-deficient recombinant mussel adhesive proteins. Considering instability DOPA in an oxidative environment, biopolymers provides a complementary cross-linking mechanism for design novel adhesives.

Eine erste direkte Untersuchung der Nanomechanik von Kation-π-Wechselwirkungen in wässrigem Medium wurde mit einem Oberflächenkraftmessgerät durchgeführt und durch theoretische Simulationen ergänzt. Das Tetraethylammonium-Ion (TEA) verhindert die Adhäsion Polytryptophan (PTrp) Poly-L-lysin (PLL) einer 100-fach höheren Empfindlichkeit als das K+-Ion (PS=Polystyrol, PTyr=Poly-L-tyrosin, ACh=Acetylcholin). As a service to our authors and readers, this journal provides supporting information...

We report on the coexistence of liquid-like and gas-like structures in supercritical fluid (SCF). The deltoid region encloses Widom line, may therefore be termed "Widom delta". Machine learning analysis simulation data shows continuous transition across delta, from to states, with fractions following a simplified two-state model. This suggests microscopic view SCF as mixture structures, where anomalous behavior near critical point originates fluctuations between two types.

Hydraulically irreversible membrane fouling is a major problem encountered during membrane-based water purification. Membrane foulants present large hydrophobic fractions, with humic acid (HA) being prevalent example of natural organic matter. Furthermore, HA contains numerous aromatic rings (π electrons), and its interactions are cause fouling. To address this issue, in study, we used the cation−π interaction, which strong noncovalent, competitive interaction water. Because strength depends...

An exceptionally low interfacial tension of a dense fluid concentrated polyelectrolyte complexes, phase-separated from biphasic known as complex coacervates, represents unique and highly sought-after materials property that inspires novel applications superior coating to wet adhesion. Despite extensive studies broad interest, the molecular structural bases for properties coacervates are unclear. Here, microphase-separated coacervate generated by mixing recombinant mussel foot protein-1...

We study the strong-coupling (SC) interaction between two like-charged membranes of finite thickness embedded in a medium higher dielectric constant. A generalized SC theory is applied along with extensive Monte Carlo simulations to image charge effects induced by multiple discontinuities this system. These lead strong counterion crowding central region intersurface space upon increasing solvent-membrane mismatch and change membrane interactions from attractive repulsive at small...

Abstract Cation–π interactions are considered to be among the most important strong noncovalent in aqueous solutions and as regulators of various biological phenomena, including adhesion, signal transduction, liquid–liquid phase separation (LLPS). Despite their significant roles, cation–π environments not systematically experimentally understood. Here, we directly examined between cationic aromatic moieties common systems using a surface forces apparatus (SFA) augmented by computational...

Complex coacervation plays an important role in various fields. Here, the influences of backbone chemistry and ionic functional groups five pairs oppositely charged polyelectrolytes on complex were investigated. These include synthetic polymers with aliphatic hydrocarbon backbones, peptides amide bonds, carbohydrates glycosidic linkages. Despite sharing identical groups, specific displayed distinct liquid/liquid liquid/solid phase separations depending polyelectrolyte mixing ratio, buffer,...

We present general arguments for the importance, or lack thereof, of structure in charge distribution counterions counterion-mediated interactions between bounding symmetrically charged surfaces. show that on mean field weak coupling level, quadrupole contributes lowest order modification to contact value theorem and thus intersurface electrostatic interactions. The image effects are non-existent level even with multipoles. On strong quadrupoles higher multipoles contribute additional terms...

Complex coacervation is an emerging liquid/liquid phase separation (LLPS) phenomenon that behaves as a membrane-less organelle in living cells. Yet while one of the critical factors for complex temperature, little analysis and research has been devoted to temperature effect on coacervation. Here, we performed cationic protamine multivalent anions (citrate tripolyphosphate (TPP)). Both mixtures (i.e., protamine/citrate protamine/TPP) underwent aqueous solution, mixture sodium chloride did...

Chitosan is a versatile bioactive polysaccharide in various industries, such as pharmaceuticals and environmental applications, owing to its abundance, biodegradability, biocompatibility, antibacterial properties. To effectively harness potential for purposes, it crucial understand the mechanisms of interaction water. This study investigates interactions between high molecular weight (HMW, >150 kDa) chitosan four different functionalized self-assembled monolayers (SAMs) at three pHs (3.0,...

Despite their neutrality, surfaces or membranes with equal amounts of positive and negative charge can exhibit long-range electrostatic interactions if the surface is heterogeneous; this happen when charges form finite-size domain structures. These domains be formed in lipid where balance different ranges strong but short-ranged hydrophobic longer-ranged repulsion result a finite, stable size. If size large enough, oppositely charged two opposing strongly correlated by interactions; these...

Syt1 (synaptotagmin 1), a major Ca2+ sensor for fast neurotransmitter release, contains tandem Ca2+-binding C2 domains (C2AB), single transmembrane α-helix and highly charged 60-residue-long linker in between. Using single-vesicle-docking content-mixing assays we found that the region of is essential its two signature functions: Ca2+-independent vesicle docking Ca2+-dependent fusion pore opening. The basic-amino-acid-rich N-terminal acidic-amino-acid-rich C-terminal region. When charge...

Supercritical fluid (SCF) is known to exhibit salient dynamic and thermodynamic crossovers an inhomogeneous molecular distribution. However, the question as what basic physics underlies these microscopic macroscopic anomalies remains open. Here, using order parameter extracted by machine learning, fraction of gas-like (or liquid-like) molecules, we find simplicity universality in SCF: First, all isotherms a given collapse onto single master curve described scaling relation. The observed...

The aggregation of inhomogeneously charged colloids with the same average charge is analyzed using Monte Carlo simulations. We find for sizes in range 10–200 nm, which similar to observed several experiments. attraction arises from strongly correlated electrostatic interactions associated increase counterion density region between particles; this effect enhanced by discreteness and mobility surface charges. Larger attract more when their charges are discrete. study as functions density,...

Counterions in a biological system are charged water and interact with macroions, which generally made up of hydrocarbons. The dielectric difference between the hydrocarbon substrates occurs naturally, may greatly affect electrostatic properties systems. Particularly for slab geometry, bulk counterions that dissolved driven to midplane because their repulsive interaction image charges. pressure two plates becomes less since low constant substrate creates stronger association surface charges...

The counterion density profile and pressure between two inhomogenously charged parallel plates are analyzed analytically numerically in the strong-coupling regime. Point charges used surface immobile. It is found that when charge distribution inhomogeneous, coupling effect becomes stronger, spatial more localized toward plate surfaces, and, thus, lower than case homogeneous.