Highly Branched Sulfated Glycopolymers as Mucin Mimetics.

Mucins are highly complex glycoproteins that form protective and lubricating barriers around epithelial surfaces, e.g., in the respiratory tract, to protect against pathogens.

Synthesis of Highly Ordered Amphiphilic Polymer Conetwork Hydrogels via the Topologically Precise Interconnection of Two Highly Incompatible Polymers.

Here, hydrophobic polyisobutylene and hydrophilic poly-(ethylene glycol), both of reasonably high molar masses, have been end-linked, yielding amphiphilic polymer conetwork (APCN) hydrogels that can self-organize in water into well-ordered lamellar structures. The cross-linking of hydrophobic and hydrophilic polymer segments produces networks that typically exhibit sphere-like nanodomains in water and in the bulk, but the orderly interconnection of relatively large and highly incompatible polymers leads to hydrogels that internally assemble into lamellae. This unprecedented result may be attributed to the weak force-field established by the presence of a minimal concentration of homogeneously distributed cross-links in the case of the present system, which must be contrasted to a higher concentration of randomly placed cross-linking points, which destroy long-range ordering in conventional APCN hydrogels.

Non-canonical self-assembly of surfactant/cosurfactant mixtures detected by combining the power of SANS and cryo-TEM.

Hypothesis: Addition of cosurfactants to surfactant micelles is normally assumed to lead, via a continuous change of the packing parameter, to a transition of spherical micelles to elongated ones, then to wormlike viscoelastic micelles and finally, via a phase transition, to planar lamellae. However, this conventional structural sequence may be different, if surfactants with variable head group size and cosurfactants that favour strongly planar structures are employed.

Experiments: A phase study was done on solutions of the nonionic surfactant Tween-20 (Tw20) with increasing amounts of added cosurfactant 2-ethylhexyl glycerine (EHG).

A multiscale time-resolved study of the nano- to millisecond structural dynamics during protein crystallization.

Protein crystallization is key to determining the structure of proteins at atomic resolution. It can occur naturally, including in pathological pathways, for instance with aquaporin and γ-crystallin proteins. A fundamental understanding of the underlying crystallization process is both technologically and biologically relevant.

Unlocking the full compositional control of hydrophilic and hydrophobic deep eutectic solvents over protein structure and stability.

Deep eutectic solvents (DESs) have emerged as powerful environments to enhance enzymatic reactions, formulate therapeutic proteins, and develop protein-based biomaterials. Despite the wide range of properties that could be achievable through the compositional design of DESs, protein solubilization only happens in a relatively narrow range of hydrophilic DESs. Here, we use surface-modification for the generalized solubilization of proteins in both hydrophilic and hydrophobic DESs.

The First Example of a Amphiphilic Polymer Conetwork Containing a Hydrophobic Oligopeptide: The Case of End-Linked Tetra[Poly(ethylene glycol)--oligo(-alanine)].

Herein we describe the development of the first amphiphilic polymer conetwork (APCN) comprising a short hydrophobic hexa(-alanine) segment being the outer block of an amphiphilic four-armed star block copolymer with inner poly(ethylene glycol) (PEG) blocks bearing benzaldehyde terminal groups and end-linked with another four-armed star PEG homopolymer (tetraPEG star) bearing aryl-substituted acylhydrazide terminal groups. The present successful synthesis that yielded the peptide-containing model APCN was preceded by several unsuccessful efforts that followed different synthetic strategies. In addition to the synthetic work, we also present the structural characterization of the peptide-bearing APCN in DO using small-angle neutron scattering (SANS).

Clustering and Sorption of Sulfolane and Pyridine onto Silicates.

Sulfolane and pyridine are used for sour gas sweetening and carbon capture, and they are found as cocontaminants in groundwater. They are known to be miscible in water, but their mixing behavior in ternary aqueous mixtures containing sulfolane, pyridine, and water is unknown. Pyridine and sulfolane are hydrogen bond acceptors, and they increase the proportion of water molecules that donate hydrogen bonds in ternary mixtures, as revealed by Fourier transform infrared spectroscopy.

Cationic and Nonionic Surfactant Micelles in a Halogen-Free Carboxylic Acid-Based Deep Eutectic Solvent.

In recent years, it has been shown that deep eutectic solvents (DES) and similar mixtures solvate and allow for self-assembly of surfactants, serving as potential "green" alternatives as solvents for, for example, templating nanomaterials or drug delivery applications. Which surfactants are soluble and how they self-assemble depends strongly on the mixture components and their molar ratio. Here, we present the surfactant behavior in halogen-free citric acid: glycerol-based systems and show how a change in the molar ratio can affect the micellization of cationic surfactants.

Impact of Mg and pH on amorphous calcium carbonate nanoparticle formation: Implications for biomineralization and ocean acidification.

Crystallization by amorphous calcium carbonate (ACC) particle attachment (CPA) is a prevalent biomineralization mechanism among calcifying organisms. A narrow, controlled size distribution of ACC nanoparticles is essential for macroscopic crystal formation via CPA. Using in situ synchrotron small-angle X-ray scattering, we demonstrate that synthetic magnesium-stabilized ACC (Mg-ACC) nanoparticles form with an exceptionally narrow size distribution near the spinodal line during liquid-liquid phase separation.

Design of thermo-responsive self-assembly of PEGylated fatty acids: Switching reversibly from tubes or vesicles to micelles at physiological temperature.

Hypothesis: The mixing of end-capped poly(ethylene glycol) (PEG) chains with 12-hydroxy stearic acid (12-HSA) molecules is a simple one-pot strategy to design thermo-responsive PEGylated self-assemblies of fatty acids with various morphology types at room temperature (multi-lamellar tubes or vesicles) that transit reversibly upon heating into small micelles around physiological temperature.

Experimental: 4 types of 4k end-capped poly(ethylene glycol) (PEG) chains, capped respectively at one end or at both ends with either 12-HSA or stearic acid (SA), were mixed with 12-hydroxy stearic acid molecules, at a low constant ratio of end capped fatty acid moieties brought by the chains to that of free 12-HSA molecules. The detailed structure of the self-assemblies of mixtures was obtained using Small Angle Neutron Scattering with contrast variation at both 20 °C and 45 °C, and their temperature-dependent rheological behavior was characterized.

The effect of phosphate buffered saline and osmotic stress on phosphatidylcholine vesicles.

Lipid vesicles are often used as models for biological membranes in soft matter studies, with an experimental environment often chosen as water. However, to simulate biologically relevant environments, the use of aqueous buffers such as phosphate-buffered saline (PBS) would be more appropriate. In this work, we study the effect of PBS on simplified membrane models with different chain lengths and saturation states, DOPC (PC C, 1,2-dioleoyl-sn-glycero-3-phosphocholine) and DMPC (PC C, 1,2-dimyristoyl-sn-glycero-3-phosphocholine), by employing small-angle neutron scattering.

Biliquid oil-in-water nanofoams and spontaneous emulsification obtained with a surfactant resistant to curvature changes.

Hypothesis: Due to its huge polar headgroup, octaoxyethylene octyl ether carboxylic acid (CECHCOOH = Akypo LF2™) is supposed not to be able to change its curvature sufficiently to form bicontinuous microemulsions. Instead, upon adding an oil to the binary water - surfactant system, excess oil could be squeezed out or a biliquid foam could form.

Experiments: An auto-dilution setup was used to record small-angle X-ray scattering data along six dilution lines in the newly established phase diagram of the ternary system 2-ethylhexanol - CECHCOOH - water.

Low Demineralized Caseins to Replace Sodium Caseinate for Application in Whipped Creams.

Caseinate is commonly used in the dairy industry for its stabilizing properties. Its functionalities are largely due to its manufacturing process involving a high level of demineralization that induces casein precipitation. To address this, the researchers are looking for alternatives to respond to consumer demands for high-quality ingredients and increase efficiency.

Rabies Virus Phosphoprotein Exhibits Thermoresponsive Phase Separation with a Lower Critical Solution Temperature.

Rabies virus (RABV) generates membrane-less liquid organelles (Negri bodies) in the cytoplasm of its host cell, where genome transcription and replication and nucleocapsid assembly take place, but the mechanisms of their assembly and maturation remain to be explained. An essential component of the viral RNA synthesizing machine, the phosphoprotein (P), acts as a scaffold protein for the assembly of these condensates. This intrinsically disordered protein forms star-shaped dimers with N-terminal negatively charged flexible arms and C-terminal globular domains exhibiting a large dipole moment.

Insertion of anionic synthetic clay in lamellar surfactant phases.

We describe the different mixed colloidal solutions that can be obtained when mixing equivalent quantities of a synthetic anionic clay to surfactants forming lamellar phases in the absence of added salt. The important quantity driving toward insertion or depletion is the osmotic pressure, of the lamellar phase and of the clay alone. Competition for water is the main driving force toward dispersion, inclusion or exclusion (phase separation).

Confinement induced change of microemulsion phase structure in controlled pore glass (CPG) monoliths.

We use small-angle neutron scattering (SANS) to investigate the structure and phase behavior of a complex fluid within meso- and macroporous matrices. Specifically, bicontinuous microemulsions of the temperature-dependent ternary system CE-water--octane are investigated in controlled pore glass (CPG) membranes with nominal pore diameters of 10 nm, 20 nm, 50 nm, and 100 nm. The scattering data were analyzed using the Teubner-Strey model and a multiphase generalization of clipped Gaussian-field models.

Influence of critical micelle concentration of choline-based long chain fatty acid soaps on their antibacterial activity against Methicillin resistant Staphylococcus aureus.

Hypothesis: Antimicrobial resistance (AMR) is a pressing global health concern. ESKAPEE pathogens, such as Methicillin-resistant Staphylococcus aureus (MRSA) are notable of concern in healthcare settings due to their resistance to critical antibiotics. To combat AMR, the development of alternatives such as bacterial membrane-active agents is crucial.

Stabilization of Non-Native Folds and Programmable Protein Gelation in Compositionally Designed Deep Eutectic Solvents.

Proteins are adjustable units from which biomaterials with designed properties can be developed. However, non-native folded states with controlled topologies are hardly accessible in aqueous environments, limiting their prospects as building blocks. Here, we demonstrate the ability of a series of anhydrous deep eutectic solvents (DESs) to precisely control the conformational landscape of proteins.

Effect of cardiolipin on the lamellarity and elongation of liposomes hydrated in PBS.

Lamellarity and shape are important factors in the formation of vesicles and determine their role in biological systems and pharmaceutical applications. Cardiolipin (CL) is a major lipid in many biological membranes and exerts a great influence on their structural organization due to its particular structure and physico-chemical properties. Here, we used small-angle X-ray and neutron scattering to study the effects of CL with different acyl chain lengths and saturations (CL, CL, CL) on vesicle morphology and lamellarity in membrane models containing mixtures of phosphatidylcholine and phosphatidylethanolamine with different acyl chain lengths and saturations (C and C ).

Dynamic Covalent Amphiphilic Polymer Conetworks Based on End-Linked Pluronic F108: Preparation, Characterization, and Evaluation as Matrices for Gel Polymer Electrolytes.

We present the development of a platform of well-defined, dynamic covalent amphiphilic polymer conetworks (APCN) based on an α,ω-dibenzaldehyde end-functionalized linear amphiphilic poly(ethylene glycol)--poly(propylene glycol)--poly(ethylene glycol) (PEG--PPG--PEG, Pluronic) copolymer end-linked with a triacylhydrazide oligo(ethylene glycol) triarmed star cross-linker. The developed APCNs were characterized in terms of their rheological (increase in the storage modulus by a factor of 2 with increase in temperature from 10 to 50 °C), self-healing, self-assembling, and mechanical properties and evaluated as a matrix for gel polymer electrolytes (GPEs) in both the stretched and unstretched states. Our results show that water-loaded APCNs almost completely self-mend, self-organize at room temperature into a body-centered cubic structure with long-range order exhibiting an aggregation number of around 80, and display an exceptional room temperature stretchability of ∼2400%.

Lead Extraction in a Functionalized and Permeable Silica-Based Porous Liquid.

Silica-based porous liquids (PLs) are innovative and versatile liquid materials with a high potential, although their application is often restricted to gas sorption. In this work, we propose to evaluate their potential to extract metals. For this goal, we have adapted their synthesis to provide PLs functionalized with thiols that are expected to chelate metallic contaminants, such as lead.

A dilute nematic gel produced by intramicellar segregation of two polyoxyethylene alkyl ether carboxylic acids.

Motivation: Surfactants like CECHCOOH have such bulky headgroups that they cannot show the common sphere-to-cylinder transition, while surfactants like CECHCOOH are mimicking lipids and form only bilayers. Mixing these two types of surfactants allows one to investigate the competition between intramicellar segregation leading to disc-like bicelles and the temperature dependent curvature constraints imposed by the mismatch between heads and tails.

Experiments: We establish phase diagrams as a function of temperature, surfactant mole ratio, and active matter content.