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1.
An insight of in vitro transport of PEGylated non-ionic surfactant vesicles (NSVs) across the intestinal polarized enterocyte monolayers.
Primavera, R, Palumbo, P, Celia, C, Cinque, B, Carata, E, Carafa, M, Paolino, D, Cifone, MG, Di Marzio, L, Cilurzo, F
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V. 2018;:432-442
Abstract
PEGylated non-ionic surfactant-based vesicles (NSVs) are promising drug delivery systems for the local, oral and systemic administrations of therapeutics. The aim of this study was to test the cellular biocompatibility and transport of Nile Red-loaded NSVs (NR-NSVs) across the Caco-2-cell monolayers, which represent an in vitro model of human intestinal epithelium. The NR-NSVs assumed a spherical shape with a mean size of 140 nm, and a narrow size distribution. The NR-NSVs did not modify Caco-2 cell viability, which remained unaltered in vitro up to a concentration of 1 mM. The transport studies demonstrated that the NR-NSVs moved across the Caco-2 monolayers without affecting the transepithelial electrical resistance. These results were supported by flow cytometry analysis, which demonstrated that NR-NSVs were internalized inside the Caco-2 cells. Nanoparticle tracking and Transmission Electron Microscopy (TEM) analysis showed the presence of NR-NSVs in the basolateral side of the Caco-2 monolayers. TEM images also showed that NSVs were transported intact across the Caco-2 monolayers, thus demonstrating a predominant transcytosis mechanism of transport through endocytosis. The NSVs did not affect the integrity of the membrane barrier in vitro, and can potentially be used in clinics to increase the oral bioavailability and delivery of therapeutics.
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2.
Importance of hydrophobic interactions in the single-chained cationic surfactant-DNA complexation.
López-López, M, López-Cornejo, P, Martín, VI, Ostos, FJ, Checa-Rodríguez, C, Prados-Carvajal, R, Lebrón, JA, Huertas, P, Moyá, ML
Journal of colloid and interface science. 2018;:197-205
Abstract
The goal of this work was to understand the key factors determining the DNA compacting capacity of single-chained cationic surfactants. Fluorescence, zeta potential, circular dichroism, gel electrophoresis and AFM measurements were carried out in order to study the condensation of the nucleic acid resulting from the formation of the surfactant-DNA complexes. The apparent equilibrium binding constant of the surfactants to the nucleic acid, Kapp, estimated from the experimental results obtained in the ethidium bromide competitive binding experiments, can be considered directly related to the ability of a given surfactant as a DNA compacting agent. The plot of ln(Kapp) vs. ln(cmc), cmc being the critical micelle concentration, for all the bromide and chloride surfactants studied, was found to be a reasonably good linear correlation. This result shows that hydrophobic interactions mainly control the surfactant DNA compaction efficiency.
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3.
Surfactant and heavy metal interaction in poplar: a focus on SDS and Zn uptake.
Pierattini, EC, Francini, A, Raffaelli, A, Sebastiani, L
Tree physiology. 2018;(1):109-118
Abstract
Surfactants are widely used detergent ingredients and, thanks to their chemical properties, they are applied for remediation of sites polluted by heavy metals and organic contaminants, both in soil flushing and in phytoremediation. However, their direct effects on tree physiology especially in consociation with heavy metal pollution, as well as their possible absorption by plants, have not been appropriately investigated. In order to evaluate plant uptake/translocation of the surfactant sodium dodecyl sulfate (SDS) and the heavy metal zinc (Zn) in Populus alba L. Villafranca clone, SDS was applied alone (0.5 mM) or in combination with Zn (1 mM). Physiological effects on plant growth and photosynthetic performance were investigated. An increasing trend of Zn translocation towards basal leaves as a consequence of SDS co-treatment (1 mM Zn + 0.5 mM SDS; P = 0.03) was observed, proving the ability of SDS to improve heavy metals translocation. However, SDS exposure (both in 0.5 mM SDS and 1 mM Zn + 0.5 mM SDS treated plants) resulted in the appearance of foliar necrosis that expanded with an acropetal trend and finally led to leaf abscission. This phenotype may be caused by the emergence of an additional stress during the experimental trial, which could be related to the dissociation of sodium (Na) ions from the dodecyl sulfate molecules in the hydroponic system. In fact, while liquid chromatography-tandem mass spectrometry measurements revealed that dodecyl sulfate is mainly retained at root levels, Na is translocated to the aerial parts of the plant.
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4.
Culture Medium Development for Microbial-Derived Surfactants Production-An Overview.
Nurfarahin, AH, Mohamed, MS, Phang, LY
Molecules (Basel, Switzerland). 2018;(5)
Abstract
Surfactants are compounds that can reduce the surface tension between two different phases or the interfacial tension of the liquid between water and oil, possessing both hydrophilic and hydrophobic moieties. Biosurfactants have traits that have proven to be advantageous over synthetic surfactants, but these compounds do not compete economically with synthetic surfactants. Different alternatives increase the yield of biosurfactants; development of an economical production process and the usage of cheaper substrates during process have been employed. One of the solutions relies on the suitable formulation of a production medium by including alternative raw materials sourced from agro-wastes, hydrocarbons, or by-products of a process might help in boosting the biosurfactant production. Since the nutritional factors required will be different among microorganisms, the establishment of a suitable formulation for biosurfactant production will be challenging. The present review describes various nutrients and elements considered in the formulation of a production medium with an approach focusing on the macronutrient (carbon, nitrogen source, and C/N ratio), minerals, vitamins, metabolic regulators, and salinity levels which may aid in the study of biosurfactant production in the future.
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5.
Chemically-Induced Production of Anti-Inflammatory Molecules in Microalgae.
Montero-Lobato, Z, Vázquez, M, Navarro, F, Fuentes, JL, Bermejo, E, Garbayo, I, Vílchez, C, Cuaresma, M
Marine drugs. 2018;(12)
Abstract
Microalgae have been widely recognized as a valuable source of natural, bioactive molecules that can benefit human health. Some molecules of commercial value synthesized by the microalgal metabolism have been proven to display anti-inflammatory activity, including the carotenoids lutein and astaxanthin, the fatty acids EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), and sulphated polysaccharides. These molecules can accumulate to a certain extent in a diversity of microalgae species. A production process could become commercially feasible if the productivity is high and the overall production process costs are minimized. The productivity of anti-inflammatory molecules depends on each algal species and the cultivation conditions, the latter being mostly related to nutrient starvation and/or extremes of temperature and/or light intensity. Furthermore, novel bioprocess tools have been reported which might improve the biosynthesis yields and productivity of those target molecules and reduce production costs simultaneously. Such novel tools include the use of chemical triggers or enhancers to improve algal growth and/or accumulation of bioactive molecules, the algal growth in foam and the surfactant-mediated extraction of valuable compounds. Taken together, the recent findings suggest that the combined use of novel bioprocess strategies could improve the technical efficiency and commercial feasibility of valuable microalgal bioproducts production, particularly anti-inflammatory compounds, in large scale processes.
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6.
Optimization of process parameters in preparation of tocotrienol-rich red palm oil-based nanoemulsion stabilized by Tween80-Span 80 using response surface methodology.
Chong, WT, Tan, CP, Cheah, YK, B Lajis, AF, Habi Mat Dian, NL, Kanagaratnam, S, Lai, OM
PloS one. 2018;(8):e0202771
Abstract
Red palm oil (RPO) is a natural source of Vitamin E (70-80% tocotrienol). It is a potent natural antioxidant that can be used in skin-care products. Its antioxidant property protects skin from inflammation and aging. In our work, a tocotrienol-rich RPO-based nanoemulsion formulation was optimized using response surface methodology (RSM) and formulated using high pressure homogenizer. Effect of the concentration of three independent variables [surfactant (5-15 wt%), co-solvent (10-30 wt%) and homogenization pressure (500-700 bar)] toward two response variables (droplet size, polydispersity index) was studied using central composite design (CCD) coupled to RSM. RSM analysis showed that the experimental data could be fitted into a second-order polynomial model and the coefficients of multiple determination (R2) is 0.9115. The optimized formulation of RPO-based nanoemulsion consisted of 6.09 wt% mixed surfactant [Tween 80/Span 80 (63:37, wt)], 20 wt% glycerol as a co-solvent via homogenization pressure (500 bar). The optimized tocotrienol-rich RPO-based nanoemulsion response values for droplet size and polydispersity index were 119.49nm and 0.286, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM, thus the optimized compositions have the potential to be used as a nanoemulsion for cosmetic formulations.
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7.
Mass Exchange and Equilibration Processes in AOT Reverse Micelles.
Eskici, G, Axelsen, PH
Langmuir : the ACS journal of surfaces and colloids. 2018;(7):2522-2530
Abstract
Reverse micelles (RMs) made with sodium bis(2-ethylhexyl)sulfosuccinate suspended in isooctane are commonly used experimental models of aqueous microenvironments. However, there are important unanswered questions about the very characteristic that makes them of interest, namely their size. To explore the factors that determine the size of RMs, all-atom molecular dynamics simulations of RMs with different sizes but the same water-loading ratio were performed. An Anton 2 machine was used so that systems of the necessary size could be extended into the microsecond timescale, and mass exchange processes could be observed. Contrary to hypothesis, there were no net gains or losses of water by diffusion between RMs of different size. However, gains and losses did occur following fusion events. RM fusion followed RM contact only when waters were present among the hydrophobic surfactant chains at the point of contact. The presence of an encapsulated 40-residue amyloid beta peptide did not directly promote RM fusion, but it quickly and efficiently terminated each fusion event. Before fusion terminated, however, the size of the peptide-containing RM increased without a corresponding change in its water-loading ratio. We conclude that the mass transfer between RMs is most likely accomplished through transient fusion events, rather than through the diffusion of component molecules through the organic phase. The behavior of the amyloid beta peptide in this system underscores its propensity to embed in, and fold in response to, multiple interactions with the surfactant layer.
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8.
The science behind skin care: Cleansers.
Draelos, ZD
Journal of cosmetic dermatology. 2018;(1):8-14
Abstract
Two of the most important skin care categories with profound dermatologic implications are cleansers and moisturizers. Cleansers are composed of alkaline soaps or the less barrier-damaging synthetic detergents, known as syndets. The lower skin irritation and dryness found with syndets are related to their reduced tendency to cause protein denaturation due to the charge density of protein-bound micelle-like surfactant aggregates. Many cleansing formulations are available for purchase to meet hygiene needs varying by sex, age, ethnicity, occupation, environment, personal preferences, and the presence or absence of skin disease. This discussion covers the science of skin cleansing.
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9.
Interplay between Antibiotic Efficacy and Drug-Induced Lysis Underlies Enhanced Biofilm Formation at Subinhibitory Drug Concentrations.
Yu, W, Hallinen, KM, Wood, KB
Antimicrobial agents and chemotherapy. 2018;(1)
Abstract
Subinhibitory concentrations of antibiotics have been shown to enhance biofilm formation in multiple bacterial species. While antibiotic exposure has been associated with modulated expression of many biofilm-related genes, the mechanisms of drug-induced biofilm formation remain a focus of ongoing research efforts and may vary significantly across species. In this work, we investigate antibiotic-induced biofilm formation in Enterococcus faecalis, a leading cause of nosocomial infections. We show that biofilm formation is enhanced by subinhibitory concentrations of cell wall synthesis inhibitors but not by inhibitors of protein, DNA, folic acid, or RNA synthesis. Furthermore, enhanced biofilm is associated with increased cell lysis, increases in extracellular DNA (eDNA) levels, and increases in the density of living cells in the biofilm. In addition, we observe similar enhancement of biofilm formation when cells are treated with nonantibiotic surfactants that induce cell lysis. These findings suggest that antibiotic-induced biofilm formation is governed by a trade-off between drug toxicity and the beneficial effects of cell lysis. To understand this trade-off, we developed a simple mathematical model that predicts changes in antibiotic-induced biofilm formation due to external perturbations, and we verified these predictions experimentally. Specifically, we demonstrate that perturbations that reduce eDNA (DNase treatment) or decrease the number of living cells in the planktonic phase (a second antibiotic) decrease biofilm induction, while chemical inhibitors of cell lysis increase relative biofilm induction and shift the peak to higher antibiotic concentrations. Overall, our results offer experimental evidence linking cell wall synthesis inhibitors, cell lysis, increased eDNA levels, and biofilm formation in E. faecalis while also providing a predictive quantitative model that sheds light on the interplay between cell lysis and antibiotic efficacy in developing biofilms.
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10.
Evaluation of three experimental in vitro models for the assessment of the mechanical cleansing efficacy of wound irrigation solutions.
Klasinc, R, Augustin, LA, Below, H, Baguhl, R, Assadian, O, Presterl, E, Kramer, A
International wound journal. 2018;(1):140-147
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Abstract
The aim of this study was to compare different wound-rinsing solutions to determine differences in the efficiency and to evaluate three different in vitro models for wound cleansing. Different wound-rinsing solutions (physiological saline solution, ringer lactate solution for wound irrigation, water and a solution containing polihexanide and the surfactant undecylenamidopropyl-betain) were applied on standardised test models (one- and three-chamber model, flow-cell method and a biofilm model), each challenged with three different standardised wound test soils. In the one-chamber model saline showed a better effect on decontaminating proteins than the ringer lactate solution. In the flow-cell method, water performed better than physiological saline solution, whereas ringer lactate solution demonstrated the lowest cleansing effect. No obvious superiority between the two electrolyte-containing solutions was detectable in the biofilm model. Unfortunately, it was not possible to assess the protein decontamination qualities of the surfactant-containing solution because of the interference with the protein measurement. The flow-cell method was able to detect differences between different rinse solutions because it works at constant flow mechanics, imitating a wound-rinsing procedure. The three-chamber and the less-pronounced modified one-chamber method as well as the biofilm model had generated inhomogeneous results.