Search Results (188)

Amphiphilic statistical copolymers are valuable synthetic macromolecules for the formation of small, well-defined nanoassemblies able to be utilized as nanocarriers for drug and/or gene delivery applications. In this work, the synthesis of amphiphilic linear statistical copolymers of the poly(benzyl methacrylate-co-dimethylaminoethyl methacrylate) [P(BzMA-co-DMAEMA)] type is described in three different comonomer compositions. Their synthesis was realized through a one-pot reversible addition-fragmentation chain transfer (RAFT) solution polymerization scheme. Further quaternization of the amine groups of DMAEMA with methyl iodide (CH₃I) resulted in cationic amphiphilic statistical copolymers. Macromolecular characterization was performed using size exclusion chromatography (SEC) and spectroscopic techniques (¹H-NMR and ATR-FTIR). The aggregation properties of the copolymers in aqueous media were studied via dynamic light scattering (DLS) and electrophoretic light scattering (ELS). Bimodal size distributions were determined in some cases. The BzMA to DMAEMA ratio determined aggregate size, with the copolymer of lower hydrophobic BzMA content producing smaller nanoparticles. Cryogenic transmission electron microscopy (cryo-TEM) showed the presence of spherical assemblies resulting from aggregation of primary micelles in the case of higher BzMA content. The copolymer aggregates experience dissociation at high salt concentration, and the pH-responsiveness of the amine precursors results in the formation of multifunctional potential nanocarriers. Full article

Cationic surfactants from quaternary ammonium compounds (QACs) are increasingly recognized as relevant micropollutants particularly following their widespread use during and after the COVID-19 pandemic. The new EU Urban Wastewater Treatment Directive (2024/3019) highlights micropollutant removal as a regulatory priority, mandating advanced treatment for their elimination. In this context, this study examined benzalkonium chloride (BAC) retention and membrane response during nanofiltration (NF) and reverse osmosis (RO), across concentrations ranging from monomeric to micellar. RO membranes achieved >97% rejection, whereas NF showed 65–96% removal strongly affected by micelle formation. Flux decline was most pronounced in RO, with relative permeability (J/J₀) decreasing to ~0.12 at 1.0 CMC, while NF membranes exhibited better hydraulic stability. Membrane active layer zeta potential measurements confirmed adsorption and charge neutralization, with shifts toward less negative values after BAC exposure. Hermia model analysis revealed that fouling was governed by cake layer formation or pore blocking, depending on membrane type and feed concentration. Full article

The emergence of membrane boundaries represents a decisive transition in the origin of life, yet the molecular nature of the earliest abiotic membranes remains uncertain. Existing models based on simple fatty acids, while experimentally tractable, often lack the environmental robustness required under fluctuating prebiotic conditions. Furthermore, the absence of clear pathways linking primitive amphiphiles to later phospholipid systems highlights the need for chemically continuous intermediate frameworks. Here, we explore borate-bridged amphiphile–carbohydrate conjugates as plausible intermediates between simple prebiotic surfactants and modern lipid bilayers. These conjugates arise from low-molecular-weight polyols—including glycerol, butane-1,2,3,4-tetraol, pentane-1,2,3,4,5-pentaol, and hexane-1,2,3,4,5,6-hexitol—reacting with long-chain alkyl ethers and borate species under alkaline conditions, enabling reversible coupling to ribose and other vicinal diol-containing sugars. This chemistry integrates three essential properties for early compartmentalization: hydrolytically robust ether-linked hydrophobic domains, multivalent and highly hydrated headgroups, and environmentally responsive borate coordination. Comparative physicochemical analysis suggests that single-tail alkylglycerol derivatives preferentially form micelles and interfacial films, while di- and tri-tail tetritol and pentitol conjugates favor lamellar assemblies and vesicle formation across realistic prebiotic pH and salinity ranges. Hexitol-based systems, particularly those bearing three hydrophobic chains, may act as membrane-stabilizing components that enhance rigidity and reduce permeability under extreme conditions. We propose that heterogeneous mixtures dominated by two-tail polyol diethers, supplemented by tri-tail stabilizers and surface-active alkylglycerols, could provide mechanically robust, pH-tunable, and sugar-decorated abiotic membranes. Such borate-mediated amphiphiles offer a chemically coherent framework linking carbohydrate stabilization, ether lipid persistence, and dynamic self-assembly, potentially representing a transitional stage in the evolutionary pathway from primitive amphiphilic films to biologically encoded membranes. Full article

A novel ocellatin-P1 isoform was isolated and purified from the skin secretion of the pepper frog Leptodactylus labyrinthicus. The crude skin secretion was fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) using a C₈ column and the peptide was subsequently purified on a reversed-phase C₁₈ column. Ocellatin-LB3 (as this isoform was named) was chemically sequenced by Edman degradation. This peptide is a linear C-terminally amidated molecule composed of 25 amino acid residues: ¹GLLDTLKGAAKNVVGGLASKVMEKL²⁵-NH₂. Synthetic ocellatin-LB3 was active against Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa and inactive against Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. In addition, the peptide reduced the Trypanosoma cruzi infection in L6 cells. At 64 µM it did not reduce erythrocytes or polymorphonuclear leukocytes, but did reduce mononuclear leukocyte counts, as detected by flow cytometry. No hemolytic activity was observed in red blood cells even at 128 µM. The peptide exhibited limited antiproliferative activity against MCF-7 and HeLa tumor cells at 128 µM. Pre-incubation with the peptide appeared to enhance N-formylmethionine-leucyl-phenylalanine (fMLP)-induced migration, indicating a potential additive or synergistic effect on human neutrophils. The three-dimensional structure of ocellatin-LB3 was investigated by circular dichroism (CD) and nuclear magnetic resonance (NMR). In the presence of sodium dodecyl sulfate (SDS), the peptide adopts an α-helical structure spanning residues Leu³–Lys²⁴, which remains largely preserved even at 95 °C. NMR Hydrogen/Deuterium (H/D) exchange experiments suggest that ocellatin-LB3 adopts a preferential orientation when interacting with SDS micelles. Based on the similarity among ocellatins, and on the physicochemical and structural properties of this peptide, a possible membrane-mediated mode of action is proposed, although this remains to be experimentally validated. Full article

The use of lecithin as an emulsifier in food supplements has increased in recent years. However, successful formation of liposomes or micelles requires an appropriate mixture of phospholipids in lecithin. To evaluate the emulsification properties of lecithin for food supplements, a reliable analytical procedure for characterizing phospholipids is necessary. A liquid chromatography–mass spectrometry method was developed to identify phospholipids in lecithin without standard reference materials. For efficient separation of phospholipids before mass spectrometric analysis, a reverse-phase high-performance liquid chromatography method was optimized using a Waters XBridge Protein BEH C4 column. The optimized chromatographic method demonstrated good linearity and precision. Molecular ions were detected in full scan mode to determine accurate mass-to-charge ratios for individual peaks in the chromatogram. A custom Python program was then used to generate a list of possible phospholipid species for each peak based on the measured mass-to-charge ratios. Tandem mass spectrometry was performed to confirm the identity of specific phospholipids by comparing experimental fragmentation patterns with theoretical predictions. Identification of the phospholipids was also confirmed with four commercially available standard reference compounds, demonstrating the reliability of the proposed approach. The developed method offers a practical and cost-effective strategy for identifying phospholipids in complex matrices, especially when standard reference compounds are unavailable. Additionally, it enables targeted selection of standard compounds for future quantitative analyses, making it a valuable tool for comprehensive lipid profiling. Full article

Reversible addition-fragmentation chain transfer mediated polymerization-induced self-assembly (RAFT-PISA) offers an efficient approach for the preparation of polymeric nanomaterials, giving access not only to common structures such as spheres, worm-like micelles and vesicles, but also to much more complex meso-objects. However, when the core forming block polymer possesses a high glass transition temperature (Tg), like poly(methyl methacrylate) or polystyrene (PS), high-order morphologies are particularly difficult to achieve since the glassy core can prevent polymer chain reorganization during PISA. To overcome this issue, we chose to perform visible light-initiated RAFT-PISA of poly(tert-butyl acrylate)-block-polystyrene (PtBA-b-PS) in solvent systems with varying degrees of polarity. More specifically, we prepared different mixtures of diisopropyl ether and ethanol and chose PtBA as macro-CTA due to its broad range of solubility. By varying the ratio between ethanol and diisopropyl ether, we could observe a transition from spherical micelles to vesicles via intermediate structures (e.g., necklace-like micelles, network-like micellar aggregates and wedding rings). This result was particularly remarkable since the experiments were performed near room temperature. We believe that these multiple morphologies were induced by the interactions between the solvent and the corona and the change in swelling of the polystyrene core with styrene monomer that facilitated its rearrangement. We anticipate that this approach could be applied to other polymeric systems with high Tgs. Full article

Dynamic covalent hydrogels exhibiting multi-responsive and antibacterial properties offer significant potential for biomedical applications, including smart wound dressings and controlled drug delivery. Herein, a series of amphiphilic quaternized copolymers (Q-C8PEG-n) with tunable quaternization degrees was synthesized from C8PEG via iodomethane addition and characterized by ¹H NMR, COSY, FTIR, UV-vis spectroscopy, DLS, TEM, and zeta potential analyses, confirming successful quaternization and micelle formation. These copolymers displayed thermosensitive behavior, with cloud point temperatures increasing due to enhanced hydrophilicity. Q-C8PEG-3 micelles, incorporating diethanolamine units, were crosslinked with phenylboronic acid-grafted hyaluronic acid (HA-PBA) to yield dynamic covalent hydrogels (Gel) through reversible boronic ester bonds stabilized by B-N coordination. The Gel exhibited multi-responsiveness, undergoing degradation in acidic or alkaline conditions and exposure to glucose or H₂O₂. SEM confirmed a porous microstructure, enabling efficient drug encapsulation, as demonstrated by the release of Nile red (NR). In vitro antibacterial tests revealed enhanced post-quaternization efficacy, with the Gel showing strong activity against S. aureus. This micelle-crosslinked platform synergistically combines tunable stimuli-responsiveness with inherent antibacterial properties, holding promise for applications in wound healing and tissue engineering. Full article

Hinokiflavone (HF), a natural C-O-C-linked biflavonoid originally isolated from Chamaecyparis obtusa, is a promising multifunctional antitumor agent. Despite challenges posed by multidrug resistance and tumor heterogeneity, HF demonstrates notable therapeutic potential through a multifaceted pharmacological profile. HF exerts broad-spectrum anticancer effects by targeting multiple oncogenic pathways, including the MDM2-p53 axis, MAPK/JNK/NF-κB signaling, ROS/JNK-mediated apoptosis, and Bcl-2/Bax-regulated mitochondrial pathways. These actions are further complemented by inhibition of cell proliferation through cell cycle arrest and suppression of metastasis via downregulation of matrix metalloproteinases and reversal of epithelial–mesenchymal transition. Additionally, HF displays antioxidant, anti-inflammatory, and antimicrobial activities, enhancing treatment efficacy. However, its clinical translation remains limited by poor aqueous solubility, low oral bioavailability, and incomplete pharmacokinetic characterization. Recent advances in nanotechnology-based formulation strategies, such as polymeric micelles and metal–organic frameworks, have enhanced HF’s bioavailability and in vivo antitumor efficacy. This review comprehensively delineates HF’s molecular mechanisms of anticancer action, evaluates its pharmacokinetics and bioformulation developments, and highlights challenges and prospects for clinical application. Integration of tumor microenvironment-responsive delivery systems with synergistic therapeutic strategies is essential to fully realize HF’s therapeutic potential, positioning it as a valuable scaffold for novel anticancer drug development. Full article

It is recognized that the ionization state of amphipathic molecules can affect the curvature and arrangement of the supramolecular structure of which they are a part due to changes in their shape and interactions with neighboring molecules. The pKa influences the overall charge of the molecule and its local environment, which in turn can cause it to pack into different structures, from planar lamellar membranes to curved micelles or reversed phases. It is also recognized, though less explored, that the supramolecular structure can, in turn, affect the pKa value of the molecule. We explored this possibility with oleic acid molecules and found that the apparent pKa changed by two pH units when the surfactant was forced to remain on a flat surface, compared to the value of the aggregate in suspension, where the molecule adopts the most stable supramolecular structure for each ionization state. The pKa shifted to higher values when fatty acid was forced to form planar structures, and the pH range in which neutral and ionic species coexist (conditions under which lamellar vesicles form spontaneously) increased. Thus, we propose that it is possible to control the ionization state of molecules adsorbed onto a surface, and consequently the surface charge, by modifying surface roughness. Full article

Reverse micelles (RMs) are versatile nanostructures traditionally formed in low-polarity organic solvents, but the need for greener alternatives has limited their broader applicability. Here, we demonstrate for the first time that a hydrophobic Natural Deep Eutectic Solvent (NADES), prepared from a simple 1:1 mixture of camphor and menthol (CM), can act as the continuous external phase for RM formation. Remarkably, CM dissolves the benchmark surfactant sodium dioctyl sulfosuccinate (AOT) at concentrations up to 0.5 M without co-surfactants and supports water solubilization up to W₀ = [H₂O]/[AOT] = 5, yielding thermodynamically stable systems. 1H and DOSY NMR analyses reveal clear structural rearrangements of the micellar interface, confirm the encapsulation of water in the polar core, and provide quantitative evidence of size modulation as a function of W₀. The resulting CM/AOT/water assemblies represent the first example of NADES-based reverse micelles, offering an easily prepared, sustainable, and biocompatible platform. This breakthrough opens new perspectives for the development of green self-assembled systems with promising applications in areas such as food technology, pharmaceuticals, and nanomedicine. Full article

In recent decades, the consumption of animal proteins has been rethought by consumers. Factors such as improved health and sustainability are key aspects of this scenario. Studies have sought innovative and sustainable technologies to improve protein extraction from alternative sources to increase their competitiveness. In this sense, the aim of this work was to combine the effects of nonconventional extraction methods on the process yield and the resulting techno-functional properties extracted from alternative proteins. The literature contains significant publications regarding the use of ultrasound (US), pulsed electric fields (PEFs), microwaves (MWs) and deep eutectic solvents (DESs) for enhancing protein extraction. Re-emerged techniques such as reverse micelles and aqueous two-phase extraction have also been reported. For this reason, the present study aimed not only to present the obtained results but also to discuss how the mechanisms associated with the aforementioned technologies impact the extraction yield and modification of proteins. In general, US tends to increase protein solubility (20–30%) and emulsifying capacity (35%); MWs can increase protein yield (25%) while reducing extraction time (50–70%); DES-based extraction tends to retain more than ~40% of the native functionality, and PEFs have demonstrated up to a 20% improvement in protein recovery. Nonconventional extraction methods have varying effects on the characteristics and quality of extracted proteins, offering benefits and challenges that should be considered when choosing the most suitable technology. The specificity related to each technology can be used to make possible interesting industrial applications involving nonanimal proteins. Full article

Elucidating amyloid formation inside biomolecular condensates requires models that resolve (i) local, chemistry specific contacts controlling β registry and (ii) mesoscale phase behavior and cluster coalescence on microsecond timescales—capabilities beyond single resolution models. We present a hybrid united atom/coarse-grained (UA–CG) force field coupling a PACE UA peptide model with the MARTINI CG framework. Cross-resolution nonbonded parameters are first optimized against all-atom side chain potentials of mean force to balance the relative strength between different types of interactions and then refined through universal parameter scaling by matching radius of gyration distributions for specific systems. We applied this approach to simulate a recently reported model system comprising the LVFFAR₉ peptide that can co-assemble into amyloid fibrils via liquid–liquid phase separation. Our ten-microsecond simulations reveal rapid droplet formation populated by micelle-like nanostructures with its inner core composed of LVFF clusters. The nanostructures can further fuse but the fusion is reaction-limited due to an electrostatic coalescence barrier. β structures emerge once clusters exceed ~10 peptides, and the LVFFAR₉ fraction modulates amyloid polymorphism, reversing parallel versus antiparallel registry at lower LVFFAR₉. These detailed insights generated from long simulations highlight the promise of our hybrid UA–CG strategy in investigating the molecular mechanisms of condensate aging. Full article

The specific features of the phase diagrams of aqueous Pluronic systems, and particularly those of reverse Pluronics, are critically important for their broad range of applications, notably as nanocarriers for anticancer molecules. This work aims to investigate the effect of increasing hydrophobicity, achieved by varying the PPO/PEO ratio and the molecular weight, on the phase behavior of three reverse Pluronics: 10R5 [(PPO)₈–(PEO)₂₂–(PPO)₈], 17R4 [(PPO)₁₄–(PEO)₂₄–(PPO)₁₄] and 31R1 [(PPO)₂₆–(PEO)₇–(PPO)₂₆]. A broad set of physical measurements, including density, sound velocity, viscosity, and surface tension, was used to characterize the physical properties of the solutions. These data were complemented by additional techniques such as direct observation, dynamic light scattering, and rheological measurements. Based on the primary measurements, molar volume, apparent adiabatic compressibility, and hydration profiles were subsequently derived. Phase diagrams were constructed for each system over concentration ranges of 0.1–90 wt.% and temperatures between 6 and 70 °C, identifying distinct regions corresponding to random networks, flower-like micelles, and micellar networks. Notably, the 31R1/water system does not form flower-like micelles, whereas both the 17R4/water and 10R5/water systems display such structures, albeit in a narrow interval, that shift toward higher concentrations and temperatures with increasing PPO/PEO ratio. Altogether, the present study provides new insights into the physicochemical behavior of reverse Pluronic systems, offering a foundation for their rational design as hydrophobic nanocarriers, either as standalone entities or in conjunction with other copolymers. Full article

Relaxation behavior of water confined in reverse micelles under temperature-induced micelle clustering is undertaken using broadband dielectric spectroscopy in frequency range 1 Hz–20 GHz. All microemulsion systems with sufficiently noticeable micelle water pool (water/surfactant molar ratio W > 10) depict three relaxation processes, in low, high and microwave frequencies, anchoring with relaxation of shell (bound) water, orientation of surfactant anions at water-surfactant interface and relaxation of bulk water confined in reverse micelles. The analysis of dielectric relaxation processes in AOT-based w/o microemulsions under temperature induced clustering of reverse micelles were made according to structural information obtained in NMR and conductometry experiments. The “wait and switch” relaxation mechanism was applied for the explanation of results for water in the bound and bulk states under spatial limitation in reverse micelles. It was shown that surfactant layer predominantly influences the bound water. The properties of water close to AOT interface are determined by strong interactions between water and ionic AOT molecules, which perturb water H-bonding network. The decrease in micelle size causes a weakening of hydrogen bonds, deformation of its steric network and reduction in co-operative relaxation effects. Full article

To enhance the signal intensity of kynurenines, which are present at trace concentrations in biological fluids, a novel analytical approach was developed, combining pressure-assisted electrokinetic injection (PAEKI) with a mixed micelle system based on sodium dodecyl sulfate (SDS) and Brij-35. The method was applied to key compounds of the kynurenine pathway, including L-tryptophan, kynurenine, 3-hydroxykynurenine, and kynurenic acid, as well as to the aromatic amino acids (AAs) L-tyrosine and L-phenylalanine. PAEKI was performed by electrokinetic injection for 2 min at −6.5 kV (reversed polarity) and 0.5 psi (3.45 kPa) using a fused silica capillary (50 cm in length, 50 µm inner diameter). The background electrolyte (BGE) consisted of 20 mM Na₂B₄O₇ (pH 9.2), 2 mM Brij-35, 20 mM SDS, and 20% (v/v) methanol (MeOH). The limit of detection (LOD) using a diode array detector (DAD) was 1.2 ng/mL for kynurenine and ranged from 1.5 to 3.0 ng/mL for the other analytes. The application of PAEKI in conjunction with micellar electrokinetic capillary chromatography (MEKC) and solid-phase extraction (SPE) of artificial urine samples resulted in a 146-fold increase in signal intensity for kynurenines compared to that observed using the hydrodynamic injection (HDI) mode. The developed method demonstrates strong potential for determining kynurenine pathway metabolites in complex biological matrices. Full article