Surfactant Self-Assembling and Critical Micelle Concentration: One Approach Fits All?

Demonstrating the Effectiveness of an Alternative to Triton X-100 for Detergent-Mediated Viral Inactivation in Biomanufacturing

Detergent-mediated viral inactivation is an important process step for ensuring viral safety of parenteral biotherapeutics, including plasma proteins and monoclonal antibodies (mAb). The conventional Triton X-100 detergent has ecological toxicity concerns and REACH classification that mandate replacement in the biopharmaceutical industry. Criteria for a replacement detergent include viral inactivation efficacy, acceptable safety and biodegradation profile, process removal, and quality suitable for parenteral drug product manufacturing. A non-ionic, C11-15 secondary alcohol ethoxylate, Deviron 13-S9 detergent, has been demonstrated to meet the necessary requirements for detergent performance. Benchmarking studies with Triton X-100 detergent demonstrate comparable performance with a panel of enveloped viruses in multiple matrices, including human IgG, clarified cell culture harvest, and fractionated plasma. Deviron 13-S9 detergent demonstrated viral inactivation efficiency comparable to or better than Triton X-100 detergent, achieving > 5 log reduction values. Critical micelle concentration was determined across different temperatures and media. Deviron 13-S9 detergent was demonstrated to be readily biodegradable according to OECD 301B guidelines. The absence of detergent binding to typical chromatography resins used in downstream purification was confirmed. The process removal of Deviron 13-S9 detergent from a protein-containing matrix was demonstrated using a protein A resin. These findings support Deviron 13-S9 detergent as a viable alternative to Triton X-100 detergent, ensuring robust viral inactivation, environmental compatibility, and alignment with regulatory requirements.

Enzymatic synthesis of stachyose-derived fatty acid mono-esters, the evaluation of their surface and interfacial properties and the capacity of certain derived emulsions to deliver resveratrol

The nutritional characteristics of the tetrasaccharide stachyose prompted its incorporation into biosurfactants through esterification with fatty acid derivatives embodying 12-22 carbon chains. The resulting esters were evaluated for their surface active effects, emulsifying properties and capacities to form emulsions capable of the selective delivery of the anti-oxidant resveratrol. While such studies have revealed that those congeners embodying longer side-chains have higher critical micelle concentrations (CMC) and lower interfacial tensions, their hydrophilic-lipophilic balance (HLB) values fell within a tight range. Those emulsions stabilized by esters with medium and longer side-chains exhibited good stabilities over the pH range 6-10 and up to 95 °C. Assessments of the in vitro digestion of the corresponding emulsions charged with resveratrol revealed the bioavailability of the anti-oxidant reached ca. 80 % and so suggesting that the title stachyose esters are distinctive and promising sugar-based surfactants for the targeted delivery of functional foods.

High performance thin layer chromatography with eluents containing SDS aided by UV- and Raman spectroscopy

The modification of non-polar silica gel plates by aqueous-organic solvent containing sodium dodecyl sulphate was investigated. The changes that occurred in the sorbent were examined using the Raman spectroscopy technique. The abovementioned technique was also involved in the investigation of carbamazepine-SDS complexes. The approach of applying the Raman spectroscopy into the investigation of the chromatographic behavior of SDS, carbamazepine and RP-18 W sorbent was presented for the first time. The effect of sodium dodecyl sulphate, SDS, concentration on the chosen drug used in neurodegenerative disorder (sulpiride, olanzapine, carbamazepine, trazodone, clomipramine, and pridinol) retention has been investigated. Such examination for these medicines has been presented for the first time for thin-layer chromatography system. Modified the mobile phase composition has resulted in the separation of the mixture containing all compounds. To confirm micellar forming, critical micelle concentration for SDS in the applied mobile phase was determined using two techniques, i.e., conductometric and spectrophotometric with azorubine as the indicator. The effect of surfactant on the solute zone shape by means of tailing and asymmetry factors has been determined. For four of the six investigated compounds, these factors have been close to 1.0. The separation efficiency measured by the height of the theoretical plate varies from 39 to 73 μm depending on the solute investigated. The method has been optimised regarding the quantitative analysis of investigated compounds, opening up new possibilities for drug analysis. In terms of the LOD values are in the range of 0.22 µg/spot to 1.67 µg/spot, whereas LOQ values are in the range of 0.66 µg/spot to 5.07 µg/spot for olanzapine and trazodone, respectively. Furthermore, the method was also applied for the quantitative analysis of the investigated compounds in pharmaceutical preparations. Such proceedings for RP-18 W TLC system containing SDS was shown for the first time. The new method has better or comparable concentration ranges regarding some of investigated compounds to those presented previously. Additionally, for the first time, a strategy involving various techniques (TLC chromatography supported by UV- and Raman spectroscopy and conductometry) for complex analysis of the separation system was presented, inspiring potential future research directions.

Palladium Complex Grafted on PEG-Based Amphiphilic Polymers as ppm Level Micellar Catalysts for Suzuki-Miyaura Coupling in Water

A series of bisphosphine-grafted amphiphilic polymers based on polyethylene glycol-poly(vinylethylene glycol) (PEG-PVEG) copolymers have been synthesized by using allylic etherification polymerization as a pivotal step. Self-assembling of the palladium complexes of the obtained amphiphilic polymers into spherical micelles has been investigated by UV-vis, DLS and TEM analysis. The outstanding catalytic performance of the present micellar palladium catalyst has been evidenced in the aqueous Suzuki-Miyaura coupling reaction, achieving remarkable efficiency even at a low catalyst loading of 100 ppm within 2 h.

Determination of Critical Micelle Concentration of Ionic and Non-Ionic Surfactants by Streaming Potential Measurements

A capillary electrophoresis system capable of measuring streaming potentials was used for the determination of critical micelle concentration (CMC) of anionic, cationic, zwitterionic and non-ionic surfactants. The CMC values of anionic surfactant sodium dodecyl sulphate (SDS), cationic surfactant cetyltrimethylammonium bromide (CTAB), zwitterionic surfactant 3-((3-cholamidopropyl) dimethylammonio)-1-propanesulfonate (CHAPS) and non-ionic surfactant polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether (Triton X-100) in water or salt solutions were determined by determining the abrupt change in the trend of streaming potential change with the surfactant concentration. The CMC values were 8.23, 0.93, 5.80 and 0.16 mM, respectively. This method was also used to demonstrate how the CMCs of SDS and CTAB change differently with temperature. The CMC of SDS decreased from 10°C to 25°C and then increased from 25°C to 40°C, whereas CTAB only increased linearly within 10°C-40°C. The capillary wall zeta potentials in surfactant solutions can be calculated from the measured streaming potential, conductivity and solution viscosity. Surface charge densities were calculated using the zeta potentials obtained. The surface charge densities of SDS were calculated to be 5.6-0.8 C/m2 when SDS solutions with concentrations of 2-20 mM zeta potentials were used. The calculated zeta potentials and surface charge densities reached a plateau at about 8 mM, which coincided with the CMC of SDS determined in the present study and the literature values. The CMC values obtained from streaming potential measurement are comparable to values obtained with other CMC determination techniques such as surface tension and conductometric measurements.

Enhancing bioavailability and functionality of plant peptides and proteins: A review of novel strategies for food and pharmaceutical applications

Plant-derived peptides and proteins are emerging as versatile bioactive ingredients in functional food and pharmaceutical sectors due to their diverse health benefits. However, their practical applications are often limited by poor bioavailability and functional instability. This review evaluates key determinants of plant peptide/protein bioactivity, including physicochemical properties, anti-nutritional components, food matrix interactions, and gastrointestinal digestion conditions. Strategies to enhance their functionality and bioavailability are systematically discussed, focusing on absorption enhancers, structural modifications, protease inhibitors, and colloidal delivery systems (e.g., liposomes, emulsions, nanoparticles). Recent advancements highlight targeted enzymatic hydrolysis and fermentation as effective methods to generate bioactive peptides with improved therapeutic properties. Additionally, physical/chemical modifications enhance stability against proteolysis and improve functional performance. Innovations in plant-derived protein-based delivery systems, such as nanoparticles, demonstrate promise in protecting bioactive compounds and optimizing bioavailability. Collectively, these approaches provide a roadmap for developing next-generation plant-protein products, addressing challenges in bioactivity retention and gastrointestinal absorption.

Cell-free synthesis system: An accessible platform from biosensing to biomanufacturing

The fundamental aspect of cell-free synthesis systems is the in vitro transcription-translation process. By artificially providing the components required for protein expression, in vitro protein production alleviates various limitations tied to in vivo production, such as oxygen supply and nutrient constraints, thus showcasing substantial potential in engineering applications. This article presents a comprehensive review of cell-free synthesis systems, with a primary focus on biosensing and biomanufacturing. In terms of biosensing, it summarizes the recognition-response mechanisms and key advantages of cell-free biosensors. Moreover, it examines the strategies for the cell-free production of intricate proteins, including membrane proteins and glycoproteins. Additionally, the integration of cell-free metabolic engineering approaches with cell-free synthesis systems in biomanufacturing is thoroughly discussed, with the expectation that biotechnology will embrace greater prosperity.

Unveiling the Interactions between Amino Acids-Based Surfactants and Lipid Bilayers: A Small Angle Neutron Scattering and Reflectivity Study

N-Acyl amino acids are biodegradable anionic amphiphilic molecules made up of linear fatty acids as hydrophobic tails and amino acids as polar heads, which are promising for their applicability in different technological fields. In the light of widening their use, a deeper understanding of their interactions with biological membranes is required, especially to further assess their toxicological profile. We investigated the interaction between N-decanoyl amino acid surfactants and phospholipid bilayers as simple in vitro models for biological membranes in comparison to sodium dodecyl sulfate using neutron scattering techniques. The information from small angle neutron scattering (SANS, q range from 0.008 to 0.25 Å-1) focusing on liposome-to-surfactant interactions and neutron reflectivity (NR, Q range measured at three incident angles θ = 0.35, 0.65, and 1.5°) focusing on lipid bilayer-to-surfactant interactions was combined to provide a detailed characterization. All amino acid surfactants (C10-alanine, C10-glycine, C10-leucine, C10-methionine, C10-serine, and C10-proline) exhibited a similar behavior in terms of incorporation in liposomes and lipid removal as well as adsorption profiles in bilayers up to their critical micelle concentration (CMC). Notably, bilayer destabilization occurred for all surfactants (except for C10-serine and C10-alanine) at a concentration between CMC and 2× CMC. Such a result demonstrates the exceptional ability of C10-serine and C10-alanine to integrate into bilayers without disruption up to concentrations as high as ∼3-4× CMC. These findings support the lower cytotoxic effect of C10-serine and C10-alanine surfactants, observed in previous studies, and provide new insights on the mechanism of interaction of N-decanoyl amino acids with lipid membranes.

Effect of Composition on the Thermo-Induced Aggregation of Poloxamer-Analogue Triblock Terpolymers

Thermoresponsive polymers hold great promise for biomedical applications due to their thermo-induced phase transitions. However, challenges including controlling transition temperatures, aggregate behavior, or complex synthesis, have limited their broader use. In this study, six ABC triblock terpolymers were synthesized via group transfer polymerization, targeting a molar mass of 8000 g/mol with varying compositions. The terpolymers consist of hydrophilic oligo(ethylene glycol) methyl ether methacrylate (average molar mass = 300 g/mol, OEGMA300), hydrophobic di(propylene glycol) methyl ether methacrylate (diPGMA), and less-hydrophilic di(ethylene glycol) methyl ether methacrylate (DEGMA). Systematic characterizations of properties related to thermo-induced aggregation, including cloud point temperature, aggregate morphology, and chain immobilization, identified a unique dual-stage phase transition in the terpolymer containing 45 wt % OEGMA300, 35 wt % diPGMA, and 20 wt % DEGMA. Instead of directly agglomerating into globular aggregates, this terpolymer transitioned from spherical micelles to vesicular species, offering valuable insights for the design of controllable and responsive polymer systems.

Diffusion Coefficient Analysis by Dynamic Light Scattering Enables Determination of Critical Micelle Concentration

The critical micelle concentration is an important property of supramolecular detergents. Two dynamic light scattering approaches have been developed for critical micelle concentration analysis, i. e., concentration-dependent light scattering intensity analysis and diffusion coefficient analysis. Their utility as complementary tools for a reproducible determination of critical micelle concentration remains to be clarified. Herein, we address the question which of the two approaches is more suitable for obtaining reproducible critical micelle concentration values. We systematically compare both approaches in context with common detergent classes and benchmark utility by means of literature values. Our results show that the diffusion coefficient analysis delivers reproducible critical micelle concentration values in aqueous solutions. Our findings outline a roadmap to guide the critical micelle concentration analysis of detergents by dynamic light scattering in the future.

Electrically Controlled Spreading of a Surfactant-Laden Droplet on a Viscoelastic Interface

Electrically induced dynamic spreading of a droplet on a soft surface is characterized by intricate interactions between the moving contact line and the substrate deformation, which are explained by a complex interaction between elastic recovery and viscous dissipation that take place simultaneously. Here, we highlight the significance of an additional modulation in the interfacial energy brought about by the distribution of surfactant molecules surrounding the droplet, which causes an increase in the droplet's spreading rate, rather than the expected decrease in it due to energy dissipation at the viscoelastic interface. We attribute this to repartitioning of the surface energy that results in the dynamic reduction in the solid-liquid interfacial tension, overcoming the substrate viscosity-induced attenuation in the spreading rate. Using a scaling theory on the ensuing change in the contact angle as the droplet spreads dynamically, we further offer quantitative insights into the observed spreading dynamics. These findings allow for the rationalization of the sensitive reliance of droplet spreading on the initial contact angle, a phenomenon that has not yet been understood, in addition to providing a scientific basis for dynamic regulation of droplet spreading on soft biomimetic interfaces.

Properties of Surface-Active Organics in Aerosol Particles Produced from Combustion of Biomass Fuels under Simulated Prescribed-Fire and Wildfire Conditions

The interfacial properties of the organic fraction of biomass burning aerosols (BBA), such as the critical micelle concentration (CMC) and surfactant composition, may vary based on the origin and moisture content of the fuel and the resulting combustion conditions. Surfactant composition, fraction of total particle mass, surface tension minimums, and CMC values of organics extracted from fresh and aged BBA produced using fuel beds from Georgia ecoregions (Piedmont, Coastal Plain, and Blue Ridge) and with fuel moisture contents representative of prescribed fires or drought-induced wildfires were measured using high resolution mass spectrometry, UV-vis spectroscopy, and pendant drop tensiometry. Surface tension minimums of organics extracted from all BBA were low (<45 mN m-1), and surfactants were ∼2% of the total particle mass. The surfactant fraction was tied to combustion conditions, with the highest fractions present in BBA produced from the most efficient (highest temperature) combustion. Aging of BBA using a potential aerosol mass oxidative flow reactor resulted in an increase in the surfactant fractions of total BBA mass. The dependence of the surfactant fraction on combustion conditions may have implications for the microphysics of BBA from wildfires and prescribed fires.

Development of Pluronic-Based Micelles from Palm Oil Bioactive Compounds Incorporated by a Dissolvable Microarray Patch to Enhance the Efficacy of Atopic Dermatitis Therapy

The high content of vitamin E, including tocopherols and tocotrienols (TCF-TTE), in palm oil (Elaeis guineensis) has made it a promising candidate for the alternative treatment of atopic dermatitis (AD). However, the limited solubility of TCF-TTE has restricted its therapeutic efficacy. In this study, pluronic-based micelles (MCs) encapsulating palm oil-derived TCF-TTE were formulated with dissolvable microarray patch-micelles (DMP-MC) using carboxymethyl cellulose (CMC) synthesized from empty fruit bunches of palm to optimize its delivery for AD. The MC was prepared using a direct dissolution method using Pluronic F68 and F127. The results showed that MC increased the solubility of TCF-TTE, which was further confirmed by an in vitro study where 90.23 ± 2.07% TCF and 4.56 ± 1.36% TTE were released compared to the unencapsulated TCF-TTE extract. Furthermore, CMC biopolymers and MC integrated into DMP-MC with polyvinylpyrrolidone (PVP) exhibited favorable physical properties, such as mechanical strength and penetration ability. DMP-MC also exhibited a better platform with lower permeation, indicating higher retention and increased localized effects on AD skin than cream-MC. Additionally, dermatokinetic profile parameters showed significant improvement. The mean residence time (MRT) parameter indicated that TCF-TTE was retained for longer times 19.28 ± 0.02 h and 20.68 ± 0.01 h. Moreover, an in vivo study revealed that DMP-MC could relieve AD symptoms more rapidly than oral doses and cream-MC, indicating that DMP-MC proved to be more efficient. Furthermore, DMP-MC showed no tissue destruction (granulation and fibrosis) in rats treated with DMP-MC on the seventh day. Therefore, this study successfully developed the MC formula in DMP-MC formulation using synthesized CMC, which could potentially improve AD's therapeutic efficacy.

Effect of polyoxylglycerides-based excipients (Gelucire®) on ketoprofen amorphous solubility and crystallization from the supersaturated state

Polyoxylglycerides-based solid mixtures, commercially known as Gelucire®, are excipients commonly used for bioavailability improvement of poorly water-soluble drugs. However, their effect on solutions containing hydrophobic drugs above crystalline solubility has not yet been explored. The goal of this study was to investigate the impact of a mix of two commercial Gelucire® with high HLB values (Gelucire®50/13 and Gelucire®48/16) on the amorphous solubility and crystallization from supersaturated solutions of ketoprofen, used as model drug. The results evidenced a strong interaction between Gelucire® components and the drug-rich nanodroplets generated upon liquid-liquid phase separation. This led to two important consequences: on one hand, the drug amorphous solubility was decreased, together with the amorphous-to-crystalline solubility ratio; on the other hand, the enlargement and coalescence of the drug-rich droplets were prevented. This stabilizing effect towards the drug-rich phase was comparable to, or even stronger than, that obtained with traditional amorphous polymers (PVP or HPMC) and contributed to inhibiting drug crystallization. Notably, the impact of Gelucire® on drug crystallization from the supersaturated state depended on its micellar behaviour: the monomeric form (below 50 μg/mL) accelerated the formation of crystals, whereas pre-micellar aggregates (50-500 μg/mL) and solubilizing micelles (above 500 μg/mL) inhibited drug crystallization. These findings will contribute to a better understanding of the behaviour of supersaturated drug solutions in the presence of Gelucire® and will facilitate the rational design of supersaturating drug delivery systems containing these excipients.

A water-responsive calix[4]resorcinarene system: self-assembly and fluorescence modulation

This study explores how water content modulates the self-assembly and fluorescence behavior of two novel calix[4]resorcinarene macrocycles. These macrocycles transition from large, flattened structures in pure THF to large giant vesicles (500-5000 nm) coexisting with small micelles (3.4-3.5 nm) as the water percentage in THF/water mixtures increases up to 53%. At higher water percentages, the assemblies become smaller, forming unimodal micelles with diameters of approximately 140-160 nm. Fluorescence quenching is observed upon water addition, attributed to nonradiative deactivation. These findings highlight water as a key regulator of the assembly and fluorescence of these calix[4]resorcinarene macrocycles, paving the way for further development of water-responsive calixarene systems.

An overview of phospholipid enriched-edge activator-based vesicle nanocarriers: new paradigms to treat skin cancer

Skin cancer poses a significant global health concern necessitating innovative treatment approaches. This review explores the potential of vesicle nanoformulation incorporating EA (edge activators) to overcome barriers in skin cancer management. The skin's inherent protective mechanisms, specifically the outermost layer called the stratum corneum and the network of blood arteries, impede the permeation of drugs. Phospholipid-enriched EA based nanoformulation offer a promising solution by enhancing drug penetration through skin barriers. EAs like Span 80, Span 20, Tween 20, and sodium cholate etc., enhance vesicles deformability, influencing drug permeation. This review discusses topical application of drugs treat skin cancer, highlighting challenges connected with the conventional liposome and the significance of using EA-based nanoformulation in overcoming these challenges. Furthermore, it provides insights into various EA characteristics, critical insights, clinical trials, and patents. The review also offers a concise overview of composition, preparation techniques, and the application of EA-based nanoformulation such as transfersomes, transliposomes, transethosomes, and transniosomes for delivering drugs to treat skin cancer. Overall, this review intends to accelerate the development of formulations that incorporate EA, which would further improve topical drug delivery and enhance therapeutic outcomes in skin cancer treatment.

Synergistic enhancing of micellization and thermodynamic properties of some Gemini cationic surfactants related to benzo[d]thiazol-3-ium bromide

Herrin, three Gemini cationic surfactants related to benzo[d]thiazol-3-ium bromide with variable hydrocarbon chain lengths (TBC n = 6, 12, and 18) were synthesized successfully and confirmed by using IR and 1HNMR spectroscopies. Critical micelle concentration and different thermodynamic properties of all surfactants under study were measured using conductivity, density, molal volume, and refractive index techniques. The Critical micelle concentration of TBC 6, TBC 12, and TBC 18 surfactants measured from the different techniques shows an acceptable agreement. The molecular weight of the investigated surfactants was decreased with the order: TBC 18 > TBC 12 > TBC 6. An increase in the magnitudes of the association constant, Gibbs free energy of micellization, molar refraction, polarizability, and binding constant proved the effect of hydrocarbon chain length on increasing surfactant's micellization as follows: TBC 18 < TBC 12 < TBC 6. The enhancement in surfactant properties was also indicated under the effect of different concentrations of inorganic salts (NaI, NaBr, NaCl, MnCl2, CuCl2, and CoCl2). This effect was measured using conductivity and refractive index measurements. Different salts were indicated to adsorb on head groups of micelles, leading to an increase in the degree of ionization of the surfactant solution and improved aggregation of the surfactant at lower concentrations. The increase in the negative value of Gibbs free energy of association in the presence of salts proved an increase in the stability of micelles formed in a 15% DMSO-water solvent at 298.15 K.

Interaction mechanism and compatibility studies of silk protein peptide (SPP) with the common surfactants SDS and DTAB

The molecular interaction of low-molecular-weight SPP with common surfactants (SDS and DTAB) is a more complicated process than has been long believed. In this work, the interaction mechanism between SDS/DTAB and SPP was proposed using multiple methods including conductivity measurements, ST, UV-vis, FT-IR, DLS, fluorescence spectroscopy, and molecular docking simulations. Moreover, the foaming properties of the mixed systems were studied, and they were evaluated as cosmetics preservatives. The effects of various surfactant and protein concentrations and ratios on compatibility and functionality were studied. Based on the results, the mechanism of complex formation was identified as a cooperative van der Waals interaction followed by hydrophobic interaction and hydrogen bonding. A simpler head group leads to easier aggregation and interaction with the SPP, the formation of smaller-sized complexes, and a weaker impact on the fluorescence intensity. Thus, SDS monomers easily aggregate on SPP chains, leading to a stronger influence on the final secondary structure of SPP. This was confirmed by multiple spectroscopy methods. Comparing its single surfactant system, the SDS-SPP solution demonstrates better foaming power and the DTAB-SPP solution shows higher bacteriostatic activity. The good compatibility between SDS/DTAB and SPP can improve the functional properties of SDS or DTAB as well as lower the optimal concentration of each component. These results provide data and theoretical support for the design of cosmetic product formulas.

The limits of prediction: Why intrinsically disordered regions challenge our understanding of antimicrobial peptides

Antimicrobial peptides (AMPs) are molecules found in most organisms, playing a vital role in innate immune defense against pathogens. Their mechanism of action involves the disruption of bacterial cell membranes, causing leakage of cellular contents and ultimately leading to cell death. While AMPs typically lack a defined structure in solution, they often assume a defined conformation when interacting with bacterial membranes. Given this structural flexibility, we investigated whether intrinsically disordered regions (IDRs) with AMP-like properties could exhibit antimicrobial activity. We tested 14 peptides from different IDRs predicted to have antimicrobial activity and found that nearly all of them did not display the anticipated effects. These peptides failed to adopt a defined secondary structure and had compromised membrane interactions, resulting in a lack of antimicrobial activity. We hypothesize that evolutionary constraints may prevent IDRs from folding, even in membrane-like environments, limiting their antimicrobial potential. Moreover, our research reveals that current antimicrobial predictors fail to accurately capture the structural features of peptides when dealing with intrinsically unstructured sequences. Hence, the results presented here may have far-reaching implications for designing and improving antimicrobial strategies and therapies against infectious diseases.

Production of Lipopeptide Biosurfactant Using Wastewater from Parboiled Paddy Rice and Evaluation of Antifungal Property of the Biosurfactant Against Two Dermatophyte Fungi

A previously isolated lipopeptide biosurfactant-producing bacterium Bacillus licheniformis SCV1 was investigated for the production of the biosurfactant using wastewater from parboiled paddy rice. The biosurfactant thus produced was evaluated for its antifungal property against dermatophyte fungi Trichophyton ajelloi and Microsporum fulvum. Results revealed that the bacterial strain reduced surface tension of the media from 56.16 ± 1 mN/m to 35 ± 0.9 mN/m within 12 h, which further shrank to 29.3 ± 1 mN/m in 24 h of incubation. The yield of the biosurfactant was 3.15 ± 0.25 g/L at 48 h of incubation. The obtained biosurfactant exhibited efficient emulsifying activity against a wide range of hydrophobic substrates such as crude oil, olive oil, engine oil, and kerosene oil used in the study. The critical micelle concentration of the biosurfactant was found to be 80 mg/L. Structural characterization using FT-IR and TLC revealed that the biosurfactant produced by the strain in the wastewater is a lipopeptide consisting of surfactin and iturin. LCMS analysis revealed that the surfactin homologs range from C12 to C17-surfactin while the iturin contains C13 to C17-iturin homologs. It also revealed an in vitro study that the biosurfactant has antifungal properties against dermatophyte fungi Trichophyton ajelloi and Microsporum fulvum. Microscopic observation of the hyphae of the treated dermatophyte revealed disruption and fissure of the mycelia. The chemical composition of the wastewater revealed that it contains adequate nutritional composition and micronutrients to support bacterial growth. This is the first report that the wastewater of parboiled paddy could be used as a low-cost substrate for the production of lipopeptide biosurfactant, and the biosurfactant could be used for preventing dermatophytes fungi.

Law and Order of Colloidal Tectonics: From Molecules to Self-Assembled Colloids

Since biochemists and biologists have progressed in understanding the mechanisms involved in living organisms, biological systems have become a source of inspiration for chemists. In this context, the concept of colloidal tectonics, describing the spontaneous formation of colloidal particles or supracolloidal structures in which the building blocks are called "tectons", has emerged. Therefore, a bottom-up edification of tectons towards (supra) colloidal structures is allowed. Each (supra) colloidal system has at least one of the following properties: amphiphilicity, predictability, versatility, commutability, and reversibility. However, for these systems to perform even more interesting functions, it is necessary for tectons to have very precise chemical and physical properties so that new properties emerge in (supra) colloidal systems. In this way, colloidal tectonics enables engineering at the nano- and micrometric level and contributes to the development of smart bioinspired systems with applications in catalysis, drug delivery, etc. In this review, an overview of the concept of colloidal tectonics is illustrated by some biotic systems. The design of abiotic (supra) colloidal systems and their applications in various fields are also addressed (notably Pickering emulsions for catalysis or drug delivery). Finally, theoretical directions for the design of novel self-assembled (supra) colloidal systems are discussed.

Aggregation, Not Micellization: Perfluorooctanoic Acid, Perfluorobutanesulfonic Acid, and Potassium Perfluorooctanesulfonate Behavior in Aqueous Solution

Surface tension, conductivity, and dynamic light scattering (DLS) measurements were used to examine the surface and bulk solution behaviors of three members of the PFAS family, perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS), and the potassium salt of perfluorooctanesulfonic acid (PFOS). Measurements were carried out in solutions having variable (acidic) pH and in solutions buffered to pH = 8.0. Surface tension data show traditional soluble surfactant behavior, and results illustrate that PFOA, PFBS, and PFOS surface activity depends sensitively on solution phase pH. The tightly packed monolayers formed by PFOA in mildly acidic solutions imply that the surface pH of PFOA solutions is several units lower than bulk. Results from conductivity experiments generally show increasing conductivity with increasing bulk solution surfactant concentration. In pH = 8.0 solutions, changes in conductivity slope with surfactant concentration suggest the onset of micelle formation at concentrations <1 mM, markedly lower than reported in literature. In general, apparent critical micelle concentrations (CMCs) determined from conductivity data agree with similar predictions made from surface tension results. DLS measurements show that at concentrations close to the predicted PFAS CMCs, objects with diameters ≤10 nm start to form. However, unlike micelles, these objects continue to grow with increasing bulk solute concentration. These aggregates form structures having diameters of 50-150 nm. Aggregate size shrinks modestly as solution phase temperature increases, and this behavior is reversible. Cryo-EM images of PFOA solutions confirm a broad distribution of particles, supporting the DLS measurements. Findings reported in this work represent the first evidence that these three EPA-regulated PFAS surfactants form aggregates rather than micelles in solution. Findings also begin to reconcile differences in reported surface behaviors that have led to CMC predictions in the literature varying by more than an order of magnitude.

Ultrasonic high-yield extraction of non-toxic fucose-containing Abroma augusta polysaccharide bearing emulsifying properties

BACKGROUND

The stem of Abroma augusta contains mucilaginous polysaccharides having numerous ethnomedicinal properties. The present work aimed to develop a scalable ultrasonic-assisted aqueous Abroma augusta mucilage (AAM) extraction (UAE) method and further explores its emulsifying property and toxicity concern.

RESULTS

The combination of ultrasonic power (750 W), solid-to-liquid ratio (1:15) and temperature (348 K) gave the highest extraction yield of 2.28% with a diffusivity value of 3.85 × 10-9 m2 s-1, which was higher than aqueous extraction method using a kinetic model based on Fick's second law of diffusion. The extracted polysaccharide showed no toxicity as measured through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay on RAW cell line. Additionally, the polysaccharide over its critical micelle concentration (400, 500, 600 and 700 μg mL-1) offered emulsifying properties with 0.5%, 1% and 5% oil (v/v). The emulsion with a polysaccharide concentration of 600 μg mL-1 with 5% oil (v/v) provides stability against coalescence for 3 days.

CONCLUSION

The overall findings indicated that UAE of AAM polysaccharide can be used for an efficient extraction method, and the obtained polysaccharide is nontoxic in nature and bears emulsifying properties. © 2024 Society of Chemical Industry.

An Overview of Film-Forming Emulsions for Dermal and Transdermal Drug Delivery

Drug delivery through the skin is a widely used therapeutic method for the treatment of local dermatologic conditions. Dermal and transdermal methods of drug delivery offer numerous advantages, but some of the most important aspects of drug absorption through the skin need to be considered. Film-forming systems (FFS) represent a new mode of sustained drug delivery that can be used to replace traditional topical formulations such as creams, ointments, pastes, or patches. They are available in various forms, including solutions, gels, and emulsions, and can be categorised as film-forming gels and film-forming emulsions. Film-forming emulsions (FFE) are designed as oil-in-water (O/W) emulsions that form a film with oil droplets encapsulated in a dry polymer matrix, thus maintaining their dispersed nature. They offer several advantages, including improved solubility, bioavailability and chemical stability of lipophilic drugs. In addition, they could improve the penetration and diffusion of drugs through the skin and enhance their absorption at the target site due to the nature of the components used in the formulation. The aim of this review is to provide an up-to-date compilation of the technologies used in film-forming emulsions to support their development and availability on the market as well as the development of new pharmaceutical forms.

Fully Atom-Efficient Solvent-Mediated Biopolymer Manufacturing: A Base Case Illustrated with Macromolecular Surfactants Tailored to Stable Polymer-Water Interfaces

This work introduces a novel 1-pot, 0-waste, 0-VOC methodology for synthesizing polymeric surfactants using acrylated epoxidized soybean oil and acrylated glycerol as primary monomers. These macromolecular surfactants are synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, allowing for tunable hydrophilic-lipophilic balance (HLB) and ionic properties. We characterize the copolymers' chemical composition and surface-active properties, and evaluate their effectiveness in forming and stabilizing emulsions of semiepoxidized soybean oil and poly(acrylated epoxidized high oleic soybean oil). Comprehensive analyses, including gel permeation chromatography, nuclear magnetic resonance spectroscopy, dynamic light scattering, particle size distribution, zeta potential, and critical micelle concentration, provide detailed insights into the copolymers and the emulsions they form. The results demonstrate that the RAFT-polymerized surfactants offer long-lasting stability and effectively disperse both common oil-in-water emulsions and highly viscous and hydrophobic polymer latexes. These surfactants outperform traditional small molecule surfactants by reducing particle size and preventing phase separation, even over extended storage periods. Stable polymer-water interfaces are achieved through HLB control, tailored by monomer composition, and the final product requires no additional purification since polymerization occurs in liquid surfactants. While small molecules contribute to rapid micelle formation, the polymeric components enhance long-term stability through steric repulsion and slower dynamics. This method enables even the emulsification of polymers with submicron particle size, which ordinarily requires emulsion polymerization. Integrating biobased polymeric surfactants with advanced polymer processing techniques opens new possibilities for transforming highly hydrophobic polymers into latexes, facilitating downstream applications. This innovation enhances the environmental sustainability of surfactant production and broadens the potential for polymer emulsification technologies. Additionally, the integrated solution-processing approach demonstrated here can be applied to other emerging polymers, where judiciously selected nonvolatile solvents facilitate the polymerization and play a role in the final application.

Modelling and impact of tensiometer plate geometry and sample volume on biosurfactant surface activity assessment

Biosurfactants are molecules with hydrophilic and hydrophobic moieties with the capacity to reduce the surface tension of water. Given the limited quantity of biosurfactant extracts in laboratories, it is recommended to use equipment that requires minimal sample quantities for detecting the presence of biosurfactants. In this work, commercial glycolipids biosurfactants (rhamnolipids or sophorolipids) were diluted in water and subjected to different analyses to obtain their minimum surface tension (ST) reduction and their critical micellar concentration (CMC). The independent variables of the study were: the geometry of platinum plate (rectangular or cylindrical), the sample volume (2, 4 and 20 mL) and the container material consisting of either glass or polytetrafluoroethylene (PTFE). The variation of ST with biosurfactant concentration was studied based on the isotherm model proposed by Li & Lu. It was observed that the profile of ST values did not vary so much using the different independent variables described, observing that platinum rectangular plate can be used for volumes of 4 mL biosurfactants instead of cylindrical plate usually recommended for volumes lower than 20 mL, the container material was also not significant based on the Pearson and Spearman statistical treatment. Moreover, well-fitting regression model results were obtained for a non-commercial biosurfactant extract obtained from a residual stream of the dairy industry, predicting values close to the observed data.

Corrosion Inhibition of Carbon Steel in Neutral Chloride Solutions Using Salts of Primary Bile Acids

Due to growing environmental concerns and regulatory pressures, the demand for environmentally friendly corrosion inhibitors has increased. Biosurfactants are biodegradable and have a low toxicity. However, very few studies have reported on their potential use as corrosion inhibitors. The present study reports the novel application of two bile salts (sodium cholate NaC and sodium chenodeoxycholate NaCDC) as environmentally friendly corrosion inhibitors for carbon steel in a neutral 20 mM NaCl solution. The results of potentiodynamic polarization and electrochemical impedance measurements showed that when added at a concentration of 5 mM, the corrosion inhibition efficiencies of NaC and NaCDC were about 60% and 85%, respectively. The poor inhibitory character of NaC was confirmed by XPS analysis, revealing the formation of oxidative corrosion products on the steel surface. For the steel sample immersed in the solution containing NaCDC, the XPS measurements showed clear evidence of the presence of an organic layer and a passive oxide film on the steel surface. While the steroidal skeleton of NaC is characterized by marked biplanarity (considering its hydrophobic and hydrophilic faces), NaCDC features a steroidal ring with a hydrophilic edge (it does not exhibit biplanarity). Thus, the self-assembly and adsorption behavior of these bile salts on the steel surface are different, leading in the case of NaCDC to form a densely packed protective organic layer.

Chitosan-carrageenan microbeads containing nano-encapsulated curcumin: Nano-in-micro hydrogels as alternative-therapeutics for resistant pathogens associated with chronic wounds

Antimicrobial resistance is an issue of global relevance for the treatment of chronic wound infections. In this study, nano-in-micro hydrogels (microbeads) of chitosan and κ-carrageenan (CCMBs) containing curcumin-loaded rhamnosomes (Cur-R) were developed. The potential of Cur-R-CCMBs for improving the antibacterial activity and sustained release of curcumin was evaluated. Curcumin-loaded rhamnosomes (rhamnolipids functionalized liposomes) had a mean particle size of 116 ± 7 nm and a surface-charge of -24.5 ± 9.4 mV. The encapsulation efficiency of curcumin increased from 42.83 % ± 0.69 % in Cur-R to 95.24 % ± 3.61 % respectively after their embedding in CCMBs. SEM revealed smooth surface morphology of Cur-R-CCMBs. FTIR spectroscopy confirmed the presence of weak electrostatic and hydrophobic interactions among curcumin, rhamnosomes, and microbeads. Cur-R-CCMBs had demonstrated significant antibacterial activity against multi-drug resistant chronic wound pathogens including Staphylococcus aureus and Pseudomonas aeruginosa. Cur-R-CCMBs also exhibited significantly higher anti-oxidant (76.85 % ± 2.12 %) and anti-inflammatory activity (91.94 % ± 0.41 %) as well as hemocompatibility (4.024 % ± 0.59 %) as compared to pristine microbeads. In vivo infection model of mice revealed significant reduction in the viable bacterial count of S. aureus (∼2.5 log CFU/mL) and P. aeruginosa (∼2 log CFU/mL) for Cur-R-CCMBs after 5 days. Therefore, nano-in-micro hydrogels can improve the overall efficacy of hydrophobic antimicrobials to develop effective alternative-therapeutics against resistant-pathogens associated with chronic wound infections.

Advancements in Surfactant Carriers for Enhanced Oil Recovery: Mechanisms, Challenges, and Opportunities

Enhanced oil recovery (EOR) techniques are crucial for maximizing the extraction of residual oil from mature reservoirs. This review explores the latest advancements in surfactant carriers for EOR, focusing on their mechanisms, challenges, and opportunities. We delve into the role of inorganic nanoparticles, carbon materials, polymers and polymeric surfactants, and supramolecular systems, highlighting their interactions with reservoir rocks and their potential to improve oil recovery rates. The discussion includes the formulation and behavior of nanofluids, the impact of surfactant adsorption on different rock types, and innovative approaches using environmentally friendly materials. Notably, the use of metal oxide nanoparticles, carbon nanotubes, graphene derivatives, and polymeric surfacants and the development of supramolecular complexes for managing surfacant delivery are examined. We address the need for further research to optimize these technologies and overcome current limitations, emphasizing the importance of sustainable and economically viable EOR methods. This review aims to provide a comprehensive understanding of the emerging trends and future directions in surfactant carriers for EOR.

Aggregation behavior of newly synthesized Gemini cationic surfactants in absence and in presence of different inorganic salts in 15% DMSO-water solvent

In this study, three Gemini cationic surfactants related to thiazol-2-amine with three hydrocarbon chain lengths including 3-hexylthiazol-3-ium (TAC6), 3-dodecylthiazol-3-ium (TAC12) and octadecylthiazol3-ium (TAC18) were prepared. Surfactant structures were confirmed with IR and 1HNMR Spectroscopies. Critical micelle concentrations for all surfactants in 15% DMSO-Water solvent were measured using conductometric, refractometric, and densitometric techniques. Thermodynamics parameters were computed and explained. Also, enhancing properties of all surfactants were indicated under the effect of two concentrations, 0.001 M and 0.01 M, of six inorganic salts including Cl-, Br-, I-, Co+2, Cu+2, and Mn+2 radicals using conductivity and refractive index measurements. All techniques used to measure critical micelles concentration showed a good convergence in measuring CMC values and the behavior of all surfactants in 15% DMSO-water solvent. Increasing the binding constant of the counter ion and association constant reflects the effect of hydrocarbon chain length increment on enhancing micelle formation, where TAC 18 was shown as the lowest CMC in all applied measurements. Modeling the density of all surfactant solutions under study indicates an increase in hydrophobic polarizability with an increase in the molecular weight of the surfactant. Inorganic salts decreased the CMC of all surfactants with the increase in Gibbs free energy of micellization which ensures easier formation of more stable micelles in the presence of a salt solution. The effect of salts on decreasing CMC for all surfactants under study was arranged in the following order: Mn+2 < Cu+2 < Co+2 for cationic radicals and I- < Br- < Cl- for anionic radicals.

The combined effect of pH and NaCl on the susceptibility of Listeria monocytogenes to rhamnolipids

The use of natural and sustainable additives, that are less aggressive to the environment, is a trend in the food industry. Rhamnolipids (RL) biosurfactants have shown potential for controlling food pathogens however, due to the presence of free carboxyl groups, the pH and ionic strength may influence the properties of such surfactants. In this study, we describe the antimicrobial activity of RL under different pH values and NaCl concentrations, towards both planktonic and biofilms of Listeria monocytogenes. RL were effective at pH 5.0 and the addition of 5 % NaCl improved the bactericidal efficacy for planktonic and sessile cells. The effect of NaCl was more pronounced at pH above 6 showing a significant increase in RL antimicrobial activity. At pH 7.0 planktonic population was eradicated by RL only when salt was present whereas biofilm viability was decreased by 5 log with MBIC varying from > 2500.0 mg/L (RL) to 39.0 mg/L (RL + 5 % NaCl). Larger vesicular and lamellar RL self-assembly structures were predominant when NaCl was present, suggesting their association with the antimicrobial activity observed. The pH and ionic strength of the medium are important parameters to be considered for the development of RL-based strategies to control L. monocytogenes.

The role of the cation and anion in aqueous liquid chromatography with sodium dodecyl sulphate and imidazolium-based ionic liquids as mobile phase reagents

BACKGROUND

In reversed-phase liquid chromatography, solute retention is primarily influenced by interactions between a nonpolar stationary phase and a moderately polar hydro-organic mobile phase, based on the solute lipophilicity. However, challenges regarding retention and peak tailing can arise due to ionic interactions between positively charged analytes and free silanols present on silica-based stationary phases. To address these challenges, incorporating surfactants and ionic liquids (ILs) into the mobile phase offers an effective solution. These additives synergistically enhance chromatographic performance through electrostatic and lipophilic interactions, which enable fine-tuning of selectivity and improved separation efficiency.

RESULTS

This study explores the chromatographic behaviour of several basic compounds in aqueous mixtures containing the anionic surfactant sodium dodecyl sulphate (SDS), above its critical micellar concentration, combined with various 1-alkyl-3-methylimidazolium-based ionic liquids (ILs) featuring chloride, tetrafluoroborate, and hexafluorophosphate anions, all without the addition of organic solvents. Specifically, this research investigates the influence of different anion types within the ILs and considers the impact of the IL cations. Analysis of solute peak profiles reveals narrow and symmetrical peaks. By introducing tetrafluoroborate and hexafluorophosphate IL anions into a mobile phase that contains an anionic surfactant, the study sheds light on the interactions occurring within the chromatographic column. This enhanced understanding of the combined effects of surfactants and ILs contributes to refining chromatographic methodologies.

SIGNIFICANCE

This research highlights the importance of carefully selecting the appropriate IL when incorporating it into a micellar mobile phase alongside SDS. This combination results in practical retention times that surpass the performance achieved with either the surfactant or IL alone in the mobile phase. The study particularly emphasises the impact of the IL anion, especially in the absence of SDS and organic solvents. This unveils interactions that are otherwise obscured in micellar and hydro-organic media, providing new insights into chromatographic dynamics.

Replacing imidazole with benz-imidazole: a promising approach to enhance the electrocatalytic performance of imidazolium based surface active ionic liquids for greener electrosynthesis

We present the synthesis of a novel benzimidazolium-based surface active ionic liquid (SAIL), 3-dodecyl-1H-3λ-benzo[d]imidazole chloride, a SAIL with excellent surface activity and self-aggregation tendency whose aqueous micellar solutions offer exceptional solubilizing capacity and electrocatalytic performance for efficient electrocarboxylation of halocarbons.

Lyotropic Aqueous 2-Picolinium Ionic Liquid Crystals and Their Shear-Induced Foams

1-Dodecyl-2-methylpyridinium bromide ([C12-2-Pic][Br]) and 1-hexadecyl-2-methylpyridinium bromide ([C16-2-Pic][Br]) are two ionic liquid crystals presenting thermotropic smectic phases above 80 °C. Aiming to take advantage of the liquid crystalline properties at lower temperatures, lyotropic aqueous systems were prepared from these two organic salts. Both systems were characterized by polarized optical microscopy (POM), X-ray powder diffraction (XRD), and fast field cycling nuclear magnetic resonance (FFC-NMR) relaxometry to assess their texture, phase structure, and molecular dynamics, respectively. The mesomorphic behavior was induced at room temperature. Moreover, the lyotropic [C12-2-Pic][Br]aq revealed a smectic phase with higher separation between layers, different from the lamellar phases found in the thermotropic system (S1 and SA), which is thermally stable up to 50 °C. Furthermore, the surfactant nature of the ionic liquids diluted solutions investigated in this work allowed the formation of foams. It was found that the precursor solutions of the lyotropic dilutions with the longest alkyl chain ([C16-2-Pic][Br]aq) originated liquid foams with more stable structures than those of [C12-2-Pic][Br]aq.

Dual function surfactants for pharmaceutical formulations: The case of surface active and antibacterial 1-tolyl alkyl biguanide derivatives

One interesting field of research in the view of developing novel surfactants for pharmaceutical and cosmetic applications is the design of amphiphiles showing further bioactive properties in addition to those commonly displayed by surface-active compounds. We propose here the chemical synthesis, and characterization of 1-o-tolyl alkyl biguanide derivatives, having different lengths of the hydrocarbon chain (C3, C6, and C10), and showing surface active and antibacterial/disinfectant activities toward both Gram-positive and Gram-negative bacteria. Both surface active properties in terms of critical micelle concentration (CMC) and surface tension at CMC (γCMC), as well as the antimicrobial activity in terms of minimum inhibitory concentrations (MICs), were strongly dependent on the length of the hydrocarbon chain. Particularly, the C6 and C10 derivatives have a good ability to decrease surface tension (γCMC <40 mN/m) at low concentrations (CMC < 12 mM) and a satisfactory antibacterial effect (MIC values between 0.230 and 0.012 mM against S. aureus strains and between 0.910 and 0.190 against P.aeruginosa strains). Interestingly, these compounds showed a disinfectant activity at the tested concentrations that was comparable to that of the reference compound chlorhexidine digluconate. All these results support the possible use of these amphiphilic compounds as antibacterial agents and disinfectants in pharmaceutical or cosmetic formulations.

Evaluation of Anticancer Efficacy of D-α-Tocopheryl Polyethylene-Glycol Succinate and Soluplus® Mixed Micelles Loaded with Olaparib and Rapamycin Against Ovarian Cancer

Purpose

Ovarian cancer has the highest mortality rate and lowest survival rate among female reproductive system malignancies. There are treatment options of surgery and chemotherapy, but both are limited. In this study, we developed and evaluated micelles composed of D-α-tocopheryl polyethylene-glycol (PEG) 1000 succinate (TPGS) and Soluplus® (SOL) loaded with olaparib (OLA), a poly(ADP-ribose)polymerase (PARP) inhibitor, and rapamycin (RAPA), a mammalian target of rapamycin (mTOR) inhibitor in ovarian cancer.

Methods

We prepared micelles containing different molar ratios of OLA and RAPA embedded in different weight ratios of TPGS and SOL (OLA/RAPA-TPGS/SOL) were prepared and physicochemical characterized. Furthermore, we performed in vitro cytotoxicity experiments of OLA, RAPA, and OLA/RAPA-TPGS/SOL. In vivo toxicity and antitumor efficacy assays were also performed to assess the efficacy of the mixed micellar system.

Results

OLA/RAPA-TPGS/SOL containing a 4:1 TPGS:SOL weight ratio and a 2:3 OLA:RAPA molar ratio showed synergistic effects and were optimized. The drug encapsulation efficiency of this formulation was >65%, and the physicochemical properties were sustained for 180 days. Moreover, the formulation had a high cell uptake rate and significantly inhibited cell migration (**p < 0.01). In the in vivo toxicity test, no toxicity was observed, with the exception of the high dose group. Furthermore, OLA/RAPA-TPGS/SOL markedly inhibited tumor spheroid and tumor growth in vivo.

Conclusion

Compared to the control, OLA/RAPA-TPGS/SOL showed significant tumor inhibition. These findings lay a foundation for the use of TPGS/SOL mixed micelles loaded with OLA and RAPA in the treatment of ovarian cancer.

Coal-Based Branched Vicinal Diol Ethoxylates Versus Guerbet Alcohol Ethoxylates: Role of Tertiary Hydroxyl Groups

Branched surfactants exhibit a lower surface tension, excellent low defoaming performance, and better wetting ability compared with linear surfactants, making them promising for applications in industrial cleaning. In this study, 2-hexyl-1-decene (C8 olefin dimer), obtained from the dimerization of 1-octene, was used as the hydrophobe to synthesize branched nonionic surfactants via hydroxylation and ethoxylation. The hydroxylation of the C8 olefin dimer to synthesize 2-hexyldecane-1,2-diol (C8 BD) using H2O2 and HCOOH was investigated systematically. Under the optimal reaction conditions (H2O2/C8 olefin dimer molar ratio: 1.5, HCOOH/C8 olefin dimer molar ratio: 4.0, reaction time: 10 h, reaction temperature: 50 °C), the conversion of the C8 olefin dimer and selectivity toward C8 BD were found to reach 99.96 and 79.89%, respectively. Further, branched nonionic surfactants (C8 BDEn) were synthesized via ethoxylation of C8 BD with ethylene oxide and characterized using FTIR, LCMS, 1H NMR, and 13C NMR techniques. The presence of a tertiary hydroxyl group in C8 BD increases the reactivity of the primary hydroxyl group, leading to a narrower range of products and lower residual substrate content. The physicochemical properties and surface properties of C8 BDEn with different degrees of ethoxylation at various concentrations were investigated and compared with those of commercially available Guerbet alcohol polyoxyethylene ethers (C8 GAEO9 and C6 GAEO9). The results show that, compared with C8 GAEO9 and C6 GAEO9, C8 BDE6 displayed a higher surface activity with a lower equilibrium surface tension (27.14 mN·m-1), superior wettability with a smaller contact angle (39.2°), better emulsification performance with a longer emulsification time of 548 s, and excellent foaming properties (initial foam volume of 11.6 mL). This strategy of utilizing coal-based α-olefins for the synthesis of branched nonionic surfactants presents a route to prepare value-added fine chemicals from coal-based resources.

The Physicochemical and Functional Properties of Biosurfactants: A Review

Surfactants, also known as surface-active agents, have emerged as an important class of compounds with a wide range of applications. However, the use of chemical-derived surfactants must be restricted due to their potential adverse impact on the ecosystem and the health of human and other living organisms. In the past few years, there has been a growing inclination towards natural-derived alternatives, particularly microbial surfactants, as substitutes for synthetic or chemical-based counterparts. Microbial biosurfactants are abundantly found in bacterial species, predominantly Bacillus spp. and Pseudomonas spp. The chemical structures of biosurfactants involve the complexation of lipids with carbohydrates (glycolipoproteins and glycolipids), peptides (lipopeptides), and phosphates (phospholipids). Lipopeptides, in particular, have been the subject of extensive research due to their versatile properties, including emulsifying, antimicrobial, anticancer, and anti-inflammatory properties. This review provides an update on research progress in the classification of surfactants. Furthermore, it explores various bacterial biosurfactants and their functionalities, along with their advantages over synthetic surfactants. Finally, the potential applications of these biosurfactants in many industries and insights into future research directions are discussed.

The Potency of Maillard Conjugates Containing Whey Protein as Natural Emulsifier

There is a continued need for the advancement of natural emulsifiers to replace synthetic emulsifiers, driven by human health concerns. This study is aimed at producing protein-polysaccharide conjugates through the Maillard reaction and at evaluating its ability as an emulsifier based on its emulsifying properties. The proteins used in this study were bovine milk whey protein and soy protein isolates, while the polysaccharides were maltodextrin and pectin. The protein-polysaccharide conjugation used a Maillard reaction under dry heating conditions. The protein and polysaccharide mass ratios were 1 : 2 and 1 : 3. The results showed that the types of proteins and polysaccharides and their mass affect the surface tension of the conjugate products. Whey protein-pectin conjugates with a mass ratio of 1 : 2 and a concentration of 1% had the lowest surface tension at 43.77 dyne/cm2. This conjugate sample also showed the highest emulsifying index at 27.20 m2/g. The conjugate powder containing pectin as a polysaccharide showed better emulsifying activity than that of those containing maltodextrin. However, the smallest droplet size of the emulsion (256.5 nm) resulted from the emulsification process using whey protein-maltodextrin conjugates as an emulsifier. The FTIR and gel electrophoresis (SDS-PAGE) analysis confirmed the conjugation formation. In general, protein-polysaccharide conjugates containing whey protein could potentially act as a natural emulsifier for food.

Experimental and Molecular Dynamics Simulation to Investigate Oil Adsorption and Detachment from Sandstone/Quartz Surface by Low-Salinity Surfactant Brines

In this study, we explore the impact of monovalent (NaCl) and divalent (CaCl2) brines, coupled with sodium dodecyl sulfate (SDS) surfactant at varying low concentrations, on the detachment and displacement of oil from sandstone rock surfaces. Employing the sessile drop method and molecular dynamics simulations, we scrutinize the behavior of the brine solutions. Our findings reveal that both low salinity and low-salinity surfactant solutions induce a gradual shift in rock wettability toward a more water-wet state. This wettability transformation is not instantaneous but evolves over time, as observed through meticulous molecular motion analyses. Through contact angle measurements and molecular dynamics simulations, we delve into the molecular motion at subpore and micropore scales on sandstone/quartz surfaces. The adsorption of surface-active agents from the oil to the oil-brine interface results in a reduced interfacial tension, significantly contributing to oil displacement. Notably, low salinity concentrations ranging from 1000 to 10,000 ppm exhibit the lowest contact angles within 30 min across all solutions. However, higher concentrations deviate from this declining trend, especially with divalent ions like Ca2+, which bridge polar molecules onto the rock surface, resulting in an increased oil-wetting state. This research unveils the intricate molecular motions involved in employing low-salinity surfactant solutions for oil detachment from surfaces. Furthermore, it provides valuable insights into the underlying forces driving oil detachment and wettability alteration.

Exploration of surface tension measurement methods for pharmaceutical excipients

Surface tension is a crucial functional indicator for various classes of pharmaceutical excipients, as highlighted in both the Pharmacopoeia of the People's Republic of China (ChP) < 9601 Guidelines for Functionality-related Characteristics of Pharmaceutical Excipients > and the United States Pharmacopoeia (USP) < 1059 Excipient Performance >. However, there are few systematic studies on surface tension measurement of pharmaceutical excipients, resulting in a lack of stable parameter support in practical applications. In this study, we aim to fill this gap by exploring three different methods for measuring surface tension. These methods were carefully developed taking into account the actual measurement process and statistical theory, thus ensuring their applicability and reliability. Through comparative analyses, we have identified the most suitable measurement methods for different classes of pharmaceutical excipients. In addition, this paper describes the surface adsorption behavior of various excipients. Therefore, this study provides valuable guidance for the determination of surface tension and the study of surface adsorption behavior, which lays the foundation for further comprehensive research in the field of surface tension of pharmaceutical excipients and the improvement of general pharmacopoeia specification.

The effect of water in THF/water mixtures on CMC, aggregation sizes, and fluorescence quenching of a new calix[4]resorcinarene macrocycle

This study explores how water content modulates the self-assembly and fluorescence behavior of a novel calixarene, C1. C1 forms large, flattened structures in pure THF, but water addition triggers a transition to smaller, unimodal clusters. A critical micellar concentration (CMC) is identified, decreasing with increasing water content. Fluorescence quenching is observed upon water addition, attributed to nonradiative deactivation. These findings highlight water as a key regulator of C1's assembly and fluorescence, paving the way for further development of water-responsive calixarene systems.

Carvacrol in ovo delivery optimization and flow dynamics in broiler chicken eggs

In ovo delivery of carvacrol, the primary active compound in oregano essential oil (OEO) has the potential to enhance gut development in broilers. This study aimed to optimize in ovo application of OEO by investigating day and site of injection and delivery of carvacrol to different embryonic tissues. In Experiment 1, 2 d of injection (embryonic day (E) 12 or 17.5) and 3 sites of injection for OEO (air cell, amniotic fluid, or yolk) were evaluated based on hatchability and posthatching performance. Experiment 2 aimed to examine the impact of combining OEO with the nonionic surfactant polysorbate 80 (p80) at ratios to carvacrol of 0:0, 0:1, 0.5:1, and 1:1 on carvacrol concentration in amniotic fluid, blood, and yolk. The concentration of carvacrol was measured at 3, 6, and 9 h after OEO injection either without (0:1) or with (1:1) p80. Injection of OEO on E12 led to a significant lower hatchability compared to E17.5 (P ≤ 0.01; Δ = 9.2%). Injecting OEO into the air cell, amniotic fluid, or yolk at E17.5 did not significantly affect hatchability and posthatching performance. The highest concentrations of carvacrol found in egg tissues were observed when injected together with surfactant at the 1:1 ratio (P ≤ 0.001; 14.45 µM, 16.64 µM, and 124.82 µM, for air cell, amniotic fluid, and yolk, respectively) compared to the 0:0, 0:1 or 0.5:1 ratios. Carvacrol was highest in the amniotic fluid and blood at the first time point (3 h postinjection) and decreased afterward (P ≤ 0.001), whereas the concentration in yolk remained elevated up to 9 h postinjection. In conclusion, the optimization of the in ovo delivery of carvacrol resulted in that early injection (E12) had negative effects on hatchability and should be avoided. The findings also suggest that using a nonionic surfactant was crucial for an effective delivery of carvacrol in ovo and the migration from amniotic fluid to yolk within 3 h. In addition, carvacrol's persistence in yolk may serve as a route for delivery into the gastrointestinal tract via the yolk stalk during the peri-hatching phase, potentially influencing gut development.

Core-Labeled Reverse Micelle-Based Supramolecular Solvents for Assisted Quick and Sensitive Determination of Amitriptyline in Wastewater

In recent years, the issue of pharmaceutical contaminants in water bodies has emerged as a significant environmental concern owing to the potential negative impacts on both aquatic ecosystems and human health. Consequently, the development of efficient and eco-friendly methods for their determination and removal is of paramount importance. In this context, the development of a surfactant ensemble sensor has been explored for hard-to-sense amphiphilic drug, i.e., amitriptyline. Herein, a pyrene-based amphiphile chemoreceptor was synthesized and characterized through various spectroscopic techniques such as 1H, 13C NMR, single-crystal XRD, FTIR, and ES-mass spectrometry. Then, dodecanoic acid (DA) and a pyrene-based receptor in a THF/water solvent system were used to generate reverse micelle-based self-aggregates of SUPRAS (SUPRAmolecular Solvent). The structural aspects, such as morphology and size, along with the stability of the SUPRAS aggregates were unfolded through spectroscopic and microscopic insights. The present investigation describes a synergistic approach that combines the unique properties of premicellar concentration of supramolecular solvent with the promising potential of pyrene-based receptor for enhanced amitriptyline extraction with simultaneous determination from water (LOD = 12 nM). To evaluate the effectiveness of the developed aggregates in real-world scenarios, experiments were conducted to determine the sensing efficiency among various pharmaceutical pollutants commonly found in water sources. The results reveal that the synergistic nanoensemble exhibits remarkable sensing ability, toward the amitriptyline (AMT) drug outperforming conventional methods.

Dynamic Oscillation and Motion of Oil-in-Water Emulsion Droplets

The interplay of interfacial tensions on droplets results in a range of self-powered motions that mimic those of living systems and serve as a tunable model to understand their complex non-equilibrium behavior. Spontaneous shape deformations and oscillations are crucial features observed in nature but difficult to incorporate in synthetic artificial systems. Here, we report sessile oil-in-water emulsions that exhibit rapid oscillating behavior. The oscillations depend on the nature and concentration of the surfactant, the chemical composition of the oil, and the wettability of the solid substrate. The rapid changes in the contact angle per oscillation are observed using side-view optical microscopy. We propose that the changes in the interfacial tension of the oil droplets is due to the partitioning of the surfactant into the oil phase and the movement of self-emulsified oil out of the parent droplets giving rise to the rhythmic variation in droplet contact-line. The ability to control and understand droplet oscillation can help model similar oscillations in out-of-equilibrium systems in nature and reproduce biomimetic behavior in artificial systems for various applications, such as microfluidic lab-on-a-chip and adaptive materials.

Enhanced Electrophoretic Depletion of Sodium Dodecyl Sulfate with Methanol for Membrane Proteome Analysis by Mass Spectrometry

Membrane proteins are underrepresented during proteome characterizations, primarily owing to their lower solubility. Sodium dodecyl sulfate (SDS) is favored to enhance protein solubility but interferes with downstream analysis by mass spectrometry. Here, we present an improved workflow for SDS depletion using transmembrane electrophoresis (TME) while retaining a higher recovery of membrane proteins. Though higher levels of organic solvent lower proteome solubility, we found that the inclusion of 40% methanol provided optimal solubility of membrane proteins, with 86% recovery relative to extraction with SDS. Incorporating 40% methanol during the electrophoretic depletion of SDS by TME also maximized membrane protein recovery. We further report that methanol accelerates the rate of detergent removal, allowing TME to deplete SDS below 100 ppm in under 3 min. This is attributed to a three-fold elevation in the critical micelle concentration (CMC) of SDS in the presence of methanol, combined with a reduction in the SDS to protein binding ratio in methanol (0.3 g SDS/g protein). MS analysis of membrane proteins isolated from the methanol-assisted workflow revealed enhanced proteome detection, particularly for proteins whose pI contributed a minimal net charge and therefore possessed reduced solubility in a purely aqueous solvent. This protocol presents a robust approach for the preparation of membrane proteins by maximizing their solubility in MS-compatible solvents, offering a tool to advance membrane proteome characterization.

Alkaline Ni-Zn Rechargeable Batteries for Sustainable Energy Storage: Battery Components, Deterioration Mechanisms, and Impact of Additives

The demand for long-term, sustainable, and low-cost battery energy storage systems with high power delivery capabilities for stationary grid-scale energy storage, as well as the necessity for safe lithium-ion battery alternatives, has renewed interest in aqueous zinc-based rechargeable batteries. The alkaline Ni-Zn rechargeable battery chemistry was identified as a promising technology for sustainable energy storage applications, albeit a considerable investment in academic research, it still fails to deliver the requisite performance. It is hampered by a relatively short-term electrode degradation, resulting in a decreased cycle life. Dendrite formation, parasitic hydrogen evolution, corrosion, passivation, and dynamic morphological growth are all challenging and interrelated possible degradation processes. This review elaborates on the components of Ni-Zn batteries and their deterioration mechanisms, focusing on the influence of electrolyte additives as a cost-effective, simple, yet versatile approach for regulating these phenomena and extending the battery cycle life. Even though a great deal of effort has been dedicated to this subject, the challenges remain. This highlights that a breakthrough is to be expected, but it will necessitate not only an experimental approach, but also a theoretical and computational one, including artificial intelligence (AI) and machine learning (ML).

Molecularly informed field theory for estimating critical micelle concentrations of intrinsically disordered protein surfactants

The critical micelle concentration (CMC) is a crucial parameter in understanding the self-assembly behavior of surfactants. In this study, we combine simulation and experiment to demonstrate the predictive capability of molecularly informed field theories in estimating the CMC of biologically based protein surfactants. Our simulation approach combines the relative entropy coarse-graining of small-scale atomistic simulations with large-scale field-theoretic simulations, allowing us to efficiently compute the free energy of micelle formation necessary for the CMC calculation while preserving chemistry-specific information about the underlying surfactant building blocks. We apply this methodology to a unique intrinsically disordered protein platform capable of a wide variety of tailored sequences that enable tunable micelle self-assembly. The computational predictions of the CMC closely match experimental measurements, demonstrating the potential of molecularly informed field theories as a valuable tool to investigate self-assembly in bio-based macromolecules systematically.