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1.
Emulsification of Surfactant on Oil Droplets by Molecular Dynamics Simulation.
Cheng, Y, Yuan, S
Molecules (Basel, Switzerland). 2020;(13)
Abstract
Heavy oil in crude oil flooding is extremely difficult to extract due to its high viscosity and poor fluidity. In this paper, molecular dynamics simulation was used to study the emulsification behavior of sodium dodecyl sulfonate (SDSn) micelles on heavy oil droplets composed of asphaltenes (ASP) at the molecular level. Some analyzed techniques were used including root mean square displacement, hydrophile-hydrophobic area of an oil droplet, potential of mean force, and the number of hydrogen bonds between oil droplet and water phase. The simulated results showed that the asphaltene with carboxylate groups significantly enhances the hydration layer on the surface of oil droplets, and SDSn molecules can change the strength of the hydration layer around the surface of the oil droplets. The water bridge structure between both polar heads of the surfactant was commonly formed around the hydration layer of the emulsified oil droplet. During the emulsification of heavy oil, the ratio of hydrophilic hydrophobic surface area around an oil droplet is essential. Molecular dynamics method can be considered as a helpful tool for experimental techniques at the molecular level.
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2.
Biotechnological Applications of Paenibacillus sp. D9 Lipopeptide Biosurfactant Produced in Low-cost Substrates.
Jimoh, AA, Lin, J
Applied biochemistry and biotechnology. 2020;(3):921-941
Abstract
The present study assesses the Paenibacillus sp. D9 lipopeptide biosurfactant synthesis in cheap substrates including functional properties and applicability for varying biotechnological processes. Different experimental setups were made for oil dispersion, heavy metals removals from contaminated environments, and washing performance. The study revealed surface tension activities of 31.7-32.7 mN/m, and maximum biosurfactant yield of more than 8 g/L. Removals of 85.90%, 98.68%, 99.97%, 63.28%, 99.93%, and 94.22% were obtained for Ca, Cu, Fe, Mg, Ni, and Zn, respectively from acid mine effluents. In comparison with chemical surfactants, there was pronounced removal of heavy metals from wastewater, contaminated sands, and vegetable matter, as well as improved oil dispersing activity. A comparative study revealed that biosurfactant was more efficient (> 60%) for removal of tomato sauce and coffee stains than chemical surfactants (< 50%). Thus, lipopeptide biosurfactants are green biomolecules reducing hazards and contaminations within the environment. The future use of this lipopeptide biosurfactant is greatly promising in biotechnology.
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3.
Role of inositol to improve surfactant functions and reduce IL-6 levels: A potential adjuvant strategy for SARS-CoV-2 pneumonia?
Laganà, AS, Unfer, V, Garzon, S, Bizzarri, M
Medical hypotheses. 2020;:110262
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Abstract
To date, the spread of SARS-CoV-2 infection is increasing worldwide and represents a primary healthcare emergency. Although the infection can be asymptomatic, several cases develop severe pneumonia and acute respiratory distress syndrome (ARDS) characterized by high levels of pro-inflammatory cytokines, primarily interleukin (IL)-6. Based on available data, the severity of ARDS and serum levels of IL-6 are key determinants for the prognosis. In this scenario, available in vitro and in vivo data suggested that myo-inositol is able to increase the synthesis and function of the surfactant phosphatidylinositol, acting on the phosphoinositide 3-kinase (PI3K)-regulated signaling, with amelioration of both immune system and oxygenation at the bronchoalveolar level. In addition, myo-inositol has been found able to decrease the levels of IL-6 in several experimental settings, due to an effect on the inositol-requiring enzyme 1 (IRE1)-X-box-binding protein 1 (XBP1) and on the signal transducer and activator of transcription 3 (STAT3) pathways. In this scenario, treatment with myo-inositol may be able to reduce IL-6 dependent inflammatory response and improve oxygenation in patients with severe ARDS by SARS-CoV-2. In addition, the action of myo-inositol on IRE1 endonuclease activity may also inhibit the replication of SARS-CoV-2, as was reported for the respiratory syncytial virus. Since the available data are extremely limited, if this potential therapeutic approach will be considered valid in the clinical practice, the necessary future investigations should aim to identify the best dose, administration route (oral, intravenous and/or aerosol nebulization), and cluster(s) of patients which may get beneficial effects from this treatment.
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4.
Predicting Drug-Target Interactions with Electrotopological State Fingerprints and Amphiphilic Pseudo Amino Acid Composition.
Wang, C, Wang, W, Lu, K, Zhang, J, Chen, P, Wang, B
International journal of molecular sciences. 2020;(16)
Abstract
The task of drug-target interaction (DTI) prediction plays important roles in drug development. The experimental methods in DTIs are time-consuming, expensive and challenging. To solve these problems, machine learning-based methods are introduced, which are restricted by effective feature extraction and negative sampling. In this work, features with electrotopological state (E-state) fingerprints for drugs and amphiphilic pseudo amino acid composition (APAAC) for target proteins are tested. E-state fingerprints are extracted based on both molecular electronic and topological features with the same metric. APAAC is an extension of amino acid composition (AAC), which is calculated based on hydrophilic and hydrophobic characters to construct sequence order information. Using the combination of these feature pairs, the prediction model is established by support vector machines. In order to enhance the effectiveness of features, a distance-based negative sampling is proposed to obtain reliable negative samples. It is shown that the prediction results of area under curve for Receiver Operating Characteristic (AUC) are above 98.5% for all the three datasets in this work. The comparison of state-of-the-art methods demonstrates the effectiveness and efficiency of proposed method, which will be helpful for further drug development.
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5.
Lipase Catalysis in Presence of Nonionic Surfactants.
Goswami, D
Applied biochemistry and biotechnology. 2020;(2):744-762
Abstract
Lipase can catalyze varieties of reactions at the interface of aqueous and organic phase. Among various alternatives to modify catalytic performance of lipase, the addition of surfactants, particularly nonionic surfactants, has been widely studied. Low concentrations of nonionic surfactants augment lipase catalysis; on increasing surfactant concentration, often the catalytic performance decreases. Mole ratio of water to (nonionic) surfactant also has a profound effect on lipase activity. Catalytic abilities of some lipases are either enhanced or reduced in the presence of all nonionic surfactants of the same type, whereas for some other lipases, nonionic surfactants of the same type have mixed effect. Nonionic surfactant even changes substrate specificity of lipase. Water-in-ionic liquid microemulsion involving nonionic surfactant often performs better than other systems in improving catalytic ability of lipase. Tween and Triton surfactants often enhance enantiomeric separation catalyzed by lipase. Nonionic surfactants significantly affect activities of immobilized lipase, being present either as a component during immobilization or as a component in reaction medium. Lipases coated with nonionic surfactants act better than reverse micelles and microemulsions containing lipase. Thus, nonionic surfactants help lipase catalyzed processes in various media to enhance production of useful compounds like flavor ester, structured lipids, optically pure compounds, and noncrystalline polymers.
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6.
Gas Crosstalk between PFPE-PEG-PFPE Triblock Copolymer Surfactant-Based Microdroplets and Monitoring Bacterial Gas Metabolism with Droplet-Based Microfluidics.
Ki, S, Kang, DK
Biosensors. 2020;(11)
Abstract
The PFPE-PEG-PFPE (Perfluoropolyether-polyethylene glycol-perfluoropolyether) surfactant has been used in droplet-based microfluidics and is known to provide high droplet stability and biocompatibility. Since this surfactant ensures the stability of droplets, droplet-based microfluidic systems have been widely used to encapsulate and analyze various biological components at the single-molecule scale, including viruses, bacteria, nucleic acids and proteins. In this study, we experimentally confirmed that gas crosstalk occurred between droplets formed by fluorinated oil and the PFPE-PEG-PFPE surfactant. E. coli K-12 bacterial cells were encapsulated with Luria-Bertani broth within droplets for the cultivation, and gas crosstalk was identified with neighboring droplets that contain phenol red. Since bacteria produce ammonia gas during its metabolism, penetration of ammonia gas initiates a color change of phenol red-containing droplets. Ammonia gas exchange was also confirmed by reacting ammonium chloride and sodium hydroxide within droplets that encapsulated. Herein, we demonstrate the gas crosstalk issue between droplets when it is formed using the PFPE-PEG-PFPE surfactant and also confirm that the density of droplet barrier has effects on gas crosstalk. Our results also suggest that droplet-based microfluidics can be used for the monitoring of living bacteria by the determination of bacterial metabolites during cultivation.
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7.
Architectures and Mechanical Properties of Drugs and Complexes of Surface-Active Compounds at Air-Water and Oil-Water Interfaces.
Sarker, DK
Current drug discovery technologies. 2019;(1):11-29
Abstract
BACKGROUND Drugs can represent a multitude of compounds from proteins and peptides, such as growth hormones and insulin and on to simple organic molecules such as flurbiprofen, ibuprofen and lidocaine. Given the chemical nature of these compounds two features are always present. A portion or portions of the molecule that has little affinity for apolar surfaces and media and on the contrary a series of part or one large part that has considerable affinity for hydrophilic, polar or charged media and surfaces. A series of techniques are routinely used to probe the molecular interactions that can arise between components, such as the drug, a range of surface- active excipients and flavor compounds, for example terpenoids and the solvent or dispersion medium. RESULTS Fifty-eight papers were included in the review, a large number (16) being of theoretical nature and an equally large number (14) directly pertaining to medicine and pharmacy; alongside experimental data and phenomenological modelling. The review therefore simultaneously represents an amalgam of review article and research paper with routinely used or established (10) and well-reported methodologies (also included in the citations within the review). Experimental data included from various sources as diverse as foam micro-conductivity, interferometric measurements of surface adsorbates and laser fluorescence spectroscopy (FRAP) are used to indicate the complexity and utility of foams and surface soft matter structures for a range of purposes but specifically, here for encapsulation and incorporation of therapeutics actives (pharmaceutical molecules, vaccines and excipients used in medicaments). Techniques such as interfacial tensiometry, interfacial rheology (viscosity, elasticity and visco-elasticity) and nanoparticle particle size (hydrodynamic diameter) and charge measurements (zeta potential), in addition to atomic force and scanning electron microscopy have proven to be very useful in understanding how such elemental components combine, link or replace one another (competitive displacement). They have also proven to be both beneficial and worthwhile in the sense of quantifying the unseen actions and interplay of adsorbed molecules and the macroscopic effects, such as froth formation, creaming or sedimentation that can occur as a result of these interactions. CONCLUSION The disclosures and evaluations presented in this review confirm the importance of a theoretical understanding of a complex model of the molecular interactions, network and present a framework for the understanding of really very complex physical forms. Future therapeutic developers rely on an understanding of such complexity to garner a route to a more successful administration and formulation of a new generation of therapeutic delivery systems for use in medicine.
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8.
Influence of surfactants on anaerobic digestion of waste activated sludge: acid and methane production and pollution removal.
He, Q, Xu, P, Zhang, C, Zeng, G, Liu, Z, Wang, D, Tang, W, Dong, H, Tan, X, Duan, A
Critical reviews in biotechnology. 2019;(5):746-757
Abstract
The objective of this study is to summarize the effects of surfactants on anaerobic digestion (AD) of waste activated sludge (WAS). The increasing amount of WAS has caused serious environmental problems. Anaerobic digestion, as the main treatment for WAS containing three stages (i.e. hydrolysis, acidogenesis, and methanogenesis), has been widely investigated. Surfactant addition has been demonstrated to improve the efficiency of AD. Surfactant, as an amphipathic substance, can enhance the efficiency of hydrolysis by separating large sludge and releasing the encapsulated hydrolase, providing more substance for subsequent acidogenesis. Afterwards, the short chain fatty acids (SCFAs), as the major product, have been produced. Previous investigations revealed that surfactant could affect the transformation of SCFA. They changed the types of acidification products by promoting changes in microbial activity and in the ratio of carbon to nitrogen (C/N), especially the ratio of acetic and propionic acid, which were applied for either the removal of nutrient or the production of polyhydroxyalkanoate (PHA). In addition, the activity of microorganisms can be affected by surfactant, which mainly leads to the activity changes of methanogens. Besides, the solubilization of surfactant will promote the solubility of contaminants in sludge, such as organic contaminants and heavy metals, by increasing the bioavailability or desorbing of the sludge.
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9.
Technical approaches to evaluate the surfactant-enhanced biodegradation of biodiesel and vegetable oils.
Montagnolli, RN, Cruz, JM, Moraes, JR, Mendes, CR, Dilarri, G, Lopes, PRM, Bidoia, ED
Environmental monitoring and assessment. 2019;(9):565
Abstract
This research compared the effects of biosurfactant on the biodegradation of biodiesel and vegetable oils while validating two conceptually diverging methodologies. The two experimental setups were successfully modeled towards the effects of biosurfactants during biodegradation. We established the equivalence of both methodologies from the data output. As expected, the biosurfactants caused an increased oil uptake, thus increasing biodegradation performance. Cooking oils were favored by the microbial consortium as a carbon source when compared with biodiesel fuel, especially after use in food preparation. However, we found that biodiesel substrate standout with the highest biodegradation rates. Our results might indicate that a rapid metabolic change from the original compound initially favored biodiesels during the assimilation of organic carbon for a set specialized microbial inoculum. The data output was successfully combined with mathematical models and statistical tools to describe and predict the actual environmental behavior of biodiesel and vegetable oils. The models confirmed and predicted the biodegradation effectiveness with biosurfactants and estimated the required timeframe to achieve satisfactory contaminant removal.
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10.
Ecotoxicity and micellization behavior of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and its mixtures with nonionic surfactant fatty alcohol-polyoxyethylene ether (AEO).
Han, W, Tan, J, Peng, L, Liu, L, Zhou, X, Zhang, W, Shi, B
Aquatic toxicology (Amsterdam, Netherlands). 2019;:105313
Abstract
Surfactant mixtures have extensive industrial applications due to their ideal properties and low ecotoxicity. However, the ecotoxicity of surfactant mixtures with different proportions and their correlation with surface properties have remained poorly investigated. In this study, the ecotoxicity and surface activity of the composites of anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and nonionic surfactant fatty alcohol-polyoxyethylene ether (AEO) in various mass ratios were assessed, and the correlation between ideal application properties and safe ecological perspective of the composites was explored. The ecotoxicity of individual SDBS, AEO, and SDBS/AEO mixtures was determined using the bioluminescence inhibition assay with Photobacterium phosphoreum, and the critical micelle concentrations (CMC) were measured by surface tension method and steady-state fluorescence spectroscopy. Sodium dodecylbenzene sulfonate (SDBS) showed a considerably higher toxicity than individual AEO and SDBS/AEO mixtures. Scanning electron microscope images illustrated the rupture of bacteria membrane induced by SDBS, and the addition of AEO alleviated the damage. According to the dose-response relationship on luminous bacteria, SDBS/AEO mixtures were divided into three groups (group I with a high proportion of SDBS, SDBSAEO = 4:1 and 3:2; group II, SDBSAEO = 1:1; group III with a high proportion of AEO, SDBSAEO = 2:3 and 1:4). The sequence of toxicity of the SDBS/AEO mixtures was group II > group III > group I, demonstrating that the toxicity of the composites was related to the mixture proportion instead of the amount of AEO added. The CMC order of SDBS/AEO mixtures was group II > group I > group III, and it was proportion dependent. Furthermore, ΔCM was defined as the difference of the experimental (CM) and ideal CMC (CMideal) of the mixed system, indicating the interaction between the two kinds of surfactants. The order of the ΔCM was group II > group III > group I, which was consistent with the sequence of the toxicity. Therefore, ΔCM can be a potential indicator for the hazardous assessment of surfactant mixtures involving high ionic strength.