Aqueous Culture Medium Research Articles

Fullerene C60 Conjugate with Folic Acid and Polyvinylpyrrolidone for Targeted Delivery to Tumor Cells.

The use of targeted drug delivery systems, including those based on selective absorption by certain receptors on the surface of the target cell, can lead to a decrease in the minimum effective dose and the accompanying toxicity of the drug, as well as an increase in therapeutic efficacy. A fullerene C60 conjugate (FA-PVP-C60) with polyvinylpyrrolidone (PVP) as a biocompatible spacer and folic acid (FA) as a targeting ligand for tumor cells with increased expression of folate receptors (FR) was obtained. Using 13C NMR spectroscopy, FT-IR, UV-Vis spectrometry, fluorometry and thermal analysis, the formation of the conjugate was confirmed and the nature of the binding of its components was established. The average particle sizes of the conjugate in aqueous solutions and cell culture medium were determined using dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The FA-PVP-C60 showed antiradical activity against •DPPH, •OH and O2•-, but at the same time, it was shown to generate 1O2. It was found that the conjugate in the studied concentration range (up to 200 μg/mL) is non-toxic in vitro and does not affect the cell cycle. To confirm the ability of the conjugate to selectively accumulate through folate-mediated endocytosis, its uptake into cells was analyzed by flow cytometry and confocal microscopy. It was shown that the conjugate is less absorbed by A549 cells with low FR expression than by HeLa, which has a high level of expression of this receptor.

Dispersion and Dosimetric Challenges of Hydrophobic Carbon-Based Nanoparticles in In Vitro Cellular Studies.

Methodologies across the dispersion preparation, characterization, and cellular dosimetry of hydrophilic nanoparticles (NPs) have been developed and used extensively in the field of nanotoxicology. However, hydrophobic NPs pose a challenge for dispersion in aqueous culture media using conventional methods that include sonication followed by mixing in the culture medium of interest and cellular dosimetry. In this study, a robust methodology for the preparation of stable dispersions of hydrophobic NPs for cellular studies is developed by introducing continuous energy over time via stirring in the culture medium followed by dispersion characterization and cellular dosimetry. The stirring energy and the presence of proteins in the culture medium result in the formation of a protein corona around the NPs, stabilizing their dispersion, which can be used for in vitro cellular studies. The identification of the optimal stirring time is crucial for achieving dispersion and stability. This is assessed through a comprehensive stability testing protocol employing dynamic light scattering to evaluate the particle size distribution stability and polydispersity. Additionally, the effective density of the NPs is obtained for the stable NP dispersions using the volumetric centrifugation method, while cellular dosimetry calculations are done using available cellular computational modeling, mirroring approaches used for hydrophilic NPs. The robustness of the proposed dispersion approach is showcased using a highly hydrophobic NP model (black carbon NPs) and two culture media, RPMI medium and SABM, that are widely used in cellular studies. The proposed approach for the dispersion of hydrophobic NPs results in stable dispersions in both culture media used here. The NP effective density of 1.03-1.07 g/cm3 measured here for black carbon NPs is close to the culture media density, resulting in slow deposition on the cells over time. So, the present methodology for dispersion and dosimetry of hydrophobic NPs is essential for the design of dose-response studies and overcoming the challenges imposed by slow particle deposition.

Antileishmanial activities of three chalcone derivatives and their association with plasma membrane rigidity as assessed by EPR spectroscopy

Novel chalcone-like compounds, LQFM332 (4), LQFM333 (5), and LQFM341 (6), were synthesized and their activity against Leishmania (L.) amazonensis was evaluated and compared. Compound 4 was synthesized from the molecular hybridization of vanillin (9) and butylated hydroxytoluene (BHT), forming a chalcone scaffold. BHT was replaced by another apocynin to give compound 5, while for compound 6 the Michael acceptor double bond from compound 4 was reduced. The IC50 values for compounds 4, 5, and 6 against the Leishmania parasite were 7, 20, and 16 µM for the promastigote form, and 19, 11, and 1 µM for the amastigote form inside infected macrophages, respectively. Electron paramagnetic resonance (EPR) spectroscopy of a lipid spin label incorporated into the parasite plasma membrane demonstrated that treatment with these compounds in culture medium causes membrane rigidity in a concentration-dependent manner, owing to oxidative processes. From the IC50 values with different cell concentrations, the membrane-water partition coefficient (KM/W) of the compounds could be estimated, as well as their concentrations in the membrane (cm50) and in the aqueous culture medium (cw50) that reduce antiproliferative activity by 50%. Values for these biophysical parameters were similar to those reported for the antileishmanial drug, miltefosine. KM/W values indicated that the compounds have high affinity for the parasite membrane, with the compound containing the BHT group having the highest affinity. Compound 5, which contained a two 4-OH-3-methoxybenzene scaffold, showed the lowest values of cw50 and cm50. Compound 6 showed that the reduction of the double bond decreased the membrane affinity and the cw50 value, but maintained the cm50, demonstrating the same activity as compound 4 for assays with higher concentration of cells. As cytotoxic activities were modulated by effects on the cell membrane, our results suggest that the primary action of the compounds is on the parasite membrane.

Drycells: Cell-suspension micro liquid marbles for single-cell picking.

Cell-picking technology is essential for cell culturing. Although the recently developed tools enable single-cell-level with a >95% aqueous culture medium, thereby acting as a powerful cell-picking tool, is reported. The proposed "drycells" are formed by spraying a cell suspension onto a powder bed of hydrophobic fumed silica nanoparticles. The particles adsorb to the droplet surface and form a superhydrophobic shell, which prevents the drycells from coalescence. The number of encapsulated cells per drycell can be controlled by adjusting the drycell size and cell-suspension concentration. Moreover, it is possible to encapsulate a pair of normal or cancerous cells and create several cell colonies within a single drycell. A sieving process can be used to sort the drycells according to size. The size of the droplet can range from one to hundreds of micrometers. The drycells are sufficiently stiff to be collected using a tweezer; however, centrifugation separates them into nanoparticles and cell-suspension layers, with the separated particles being recyclable. Various handling techniques, such as splitting coalescence and inner liquid replacement, can be used. We believe that the application of the proposed drycells will greatly improve the accessibility and productivity of single-cell analysis. This article is protected by copyright. All rights reserved.

Correlation Relationship between Phase Inversion of Pickering Emulsions and Biocatalytic Activity of Microbial Transformation of Phytosterols

Microbial transformation of hydrophobic phytosterols into the pharmaceutical steroid precursors AD (androst-4-ene-3, 17-dione) and ADD (androst-4-diene-3, 17-dione) in a water–plant oil two-phase system by Mycolicibacterium neoaurum is a paradigm of interfacial biocatalysis in Pickering emulsions stabilized by bacterial cells. In the present work, phase inversion of Pickering emulsions—i.e., Pickering emulsions turning from water-in-oil (W/O) emulsions into oil-in-water (O/W) ones—was observed during microbial transformation in the presence of high concentrations of crystal phytosterols. It was found that there is a correlation relationship between the phase behaviors of Pickering emulsions and the biocatalytic activity of utilizing M. neoaurum as a whole-cell catalyst. Efficient microbial transformation under the high crystal phytosterol loadings was achieved due to the formation of O/W emulsions where interfacial biocatalysis took place. Under the optimal conditions (volume ratio of soybean oil to water: 15:35 mL, phytosterols concentration in the soybean oil: 80 g/L, glucose as co-substrate in the aqueous culture medium: 10 g/L), the concentrations of AD and ADD reached 4.8 g/L based on the whole broth (16 g/L based on the oil phase) after microbial transformation for 9 days.

Use of Pressurized and Airlift Bioreactors for Citric Acid Production by Yarrowia lipolytica from Crude Glycerol

Citric acid production is generally carried out in an aqueous medium in stirred tank reactors (STR), where the solubility of oxygen is low and the oxygen demand of microbial cultures is high. Thus, for this bioprocess, providing adequate oxygen mass transfer rate (OTR) from the gas phase into the aqueous culture medium is the main challenge of bioreactor selection and operation. In this study, citric acid production by Yarrowia lipolytica W29 from crude glycerol, in batch cultures, was performed in two non-conventional bioreactors normally associated with high mass transfer efficiency: a pressurized STR and an airlift bioreactor. Increased OTR was obtained by raising the total air pressure in the pressurized STR and by increasing the aeration rate in the airlift bioreactor. An improvement of 40% in maximum citric acid titer was obtained by raising the air pressure from 1 bar to 2 bar, whereas, in the airlift bioreactor, a 30% improvement was attained by increasing the aeration rate from 1 vvm to 1.5 vvm. Both bioreactor types can be successfully applied for the citric acid production process using alternative ways of improving OTR than increasing mechanical stirring power input, thus leading to important operating saving costs.

ИСПОЛЬЗОВАНИЕ ЛАЗЕРНОГО ИМПУЛЬСНОГО ИЗЛУЧЕНИЯ И РАСТВОРОВ ЭКОПЕРОКСИДА ДЛЯ АКТИВАЦИИ СЕМЯН САХАРНОЙ СВЕКЛЫ

Sugar beet, a biennial industrial agricultural crop, is used for the production of ethanol, biofuels, sugar and contains up to 70% sucrose. It is difficult to obtain seeds, the collection of which takes place in the second year of cultivation of root crops. The possibility of accelerating seed activation, increasing germination by methods of pre-sowing treatment of dry seeds: laser pulsed radiation and ecoperoxide solutions was studied. The first test indicating the beginning of seed awakening (one hour after treatment) was a test for determining the release of metabolites into the aqueous culture medium. The metabolites determined by spectrophotometry. They have a characteristic absorption spectrum in the UV region with a clear maximum at λmax – 207 nm and absorption up to the boundary with the visible region of 
 λmax – 330 nm. A copper vapor laser was used. Parameters: simultaneous generation of two wavelengths – green 510.5 nm and yellow 578.2 nm. The duration of the radiation pulse is 15 ns, the repetition rate is 10 kHz. The irradiation time is 10, 20, 90 s. The greatest effect of seed germination stimulation at 10 s of irradiation exceeded the control by 30%. Increasing the interval to 24 hours or more between irradiation and placing seeds for germination reduced the number of germinated seeds. Ecoperoxide was obtained by high-energy non-contact exposure to distilled water with high-voltage electric discharge streamers. An increase in seed germination by 30-40% was noted when they came into contact with a peroxide solution for 30 minutes.

Effect of ferulic and cinnamic acids on the functional and antimicrobial properties in thermo-processed PLA films

The incorporation of ferulic or cinnamic acids as antimicrobial agents into PLA matrices to produce films with active properties for food packaging applications is evaluated in this study. The acids were incorporated by thermal processing at 1 and 2 wt% presenting good stability with 84–98% retentions. The addition of acids provoked about a 5% reduction of elastic modulus and up to 20% reduction in the resistance to break in the PLA films, slightly decreasing their extensibility. Oxygen and water vapor barrier capacities were enhanced by about 6% and 45% respectively for the highest acid concentrations. The acids did not change the glass transition of the polymer but increased the thermal resistance. No significant antimicrobial activity was detected, despite the proven activity of the acids, due to their limited release into the aqueous culture media. Release kinetic studies revealed that significant release was only achieved in intermediate polarity simulant (50% aqueous ethanol), where the final percentages of the active released increased along with the total amount in the films (15% and 31%, respectively, for 2% of ferulic and cinnamic acids). Further studies are necessary to improve the compound release into food matrices and antimicrobial effectiveness.

Chitosan/oleamide nanofluid as a significant medium for enhancing gas utilization efficiency in C1-gas microbial biotransformation

Microbial biotransformation of C1 gas feedstocks such as CH4 and CO is a notable technique for sustainable, carbon–neutral chemical and fuel production. However, low C1-gas utilization efficiency in biological processes has hampered the efficient production of value-added materials, despite efficient, nonnative strains having been recently developed. Here, we constructed a nanofluid material mainly composed of chitosan and oleamide (CS/OA), which was stably suspended with a particle size of 120.7 ± 39.0 nm in aqueous culture media below pH 7.5 and attached to the cell surface, leading to a change in hydrodynamic properties mainly due to the decrease of surface tension and a decrease in mass-transfer resistance on the cell surface. The nanofluid was applied to three C1-gas-utilizing strains, Methylomonas sp. DH-1 (a type I methanotroph), Methylosinus trichosporium OB3b (a type II methanotroph), and Thermococcus onnurineus NA1 156 T (a hyperthermophilic CO-utilizing archaeon). Changes in culture media and cell membranes from the applied CS/OA nanoparticles increased specific cell growth rates (μmax). Remarkably, the strains adapted from the seed culture using the CS/OA nanofluid media also had increased μmax in a subsequent subculture and the main culture using conventional culture media, resulting in higher C1 gas consumption, cell growth, and metabolite production, such as succinate production. These results showed that the CS/OA nanofluid could be an effective medium to increase gas utilization efficiency and cell growth, and it is expected that the nanofluid can be widely used for increasing the production of value-added metabolites in C1-gas microbial biotransformation.

Preparation of Tubular Biocellulose Implants and Its Use in Surgery—A Review

This review highlights the current state regarding the preparation and characterization of tubular biocellulose materials as well as their application and application potential with a special focus on abdominal oncologic surgery. Biocellulose is a natural polymer synthesized by acetic acid bacteria from low molecular sugars and alcohols as a mechanically stable nanofiber network at the interface between the aqueous culture medium and air. This hydrogel is characterized by very high purity and biocompatibility, dimensional stability, and good surgical handling. With this property profile, biocellulose proves to be a promising candidate for the development of novel medical soft tissue implants. This requires close R&D cooperation between chemists, material scientists, biotechnologists, and surgeons. In this sense, this review spans from the natural polymer to the design of biocellulose implants and surgical suitability. It is also a concern of this article to show concretely the great need for such implants and the fields of application in oncological abdominal surgery where tubular biocellulose is or could be the focus of research. Furthermore, a critical assessment for the use of biocellulose materials concerning incidence malignancy and surgical interventions, complication rates, and current studies is emphasized. The regeneration of damaged bile ducts by the use of biocellulose implants is a first example.

Microcarrier-Supported Culture of Chondrocytes in Continuously Rocked Disposable Bioreactor.

Disposable wave-assisted bioreactors are devices originally designed for scaling-up cultures of extremely fragile animal cells. In such bioreactors, agitation is achieved by continuous horizontal oscillations of disposable culture bag-like container fixed in a rocker unit. The continuous rocking movement of the container induces waves in the two-phase (i.e., gas-liquid) culture system composed of CO2-enriched air and aqueous culture medium. Such continuously oscillating devices can be utilized for supporting homogeneity in systems for in vitro propagation of animal anchorage-dependent, that is, adherent, cells, like CP5 chondrocytes cells. As most of in vitro cultured cells exhibit anchorage-dependency toward solid surface, the suitable interface can be provided by beads of microcarriers made of polymers and characterized by large surface-to-volume ratio. This chapter describes a methodology for efficient propagation of CP5 chondrocytes on Cytodex 3 microcarriers performed in ReadyToProcess WAVE 25 disposable bioreactor, as well as all useful procedures for daily monitoring the growth of CP5 chondrocytes.

Lactate adsorption by layered double hydroxides in aqueous solution and cell culture medium

When cells proliferate in a culture medium, metabolites such as lactic acid gradually accumulate and eventually hinder cell growth. Herein, we considered various layered double hydroxides (LDH) and layered double oxides (LDO) for the selective removal of lactate in aqueous solution and a culture medium by anion exchange. NO3•Mg-Al LDH showed high lactate adsorption, low adsorption of glucose (a nutrient in culture medium), appropriate pH stability, and low cytotoxicity within a limited contact time. In contrast, NO3•Ni-Al LDH, NO3•Ca-Al LDH, Mg-Al LDO, and Cl•Mg-Al LDH had a lower performance than NO3•Mg-Al LDH. To further improve the performance, the anion of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, a common pH buffer in culture media) was tested as the intercalated anion in Mg-Al LDH. HEPES•Mg-Al LDH (Mg/Al = 2) was found to be the most promising adsorbent for culture medium regeneration because its adsorption behavior was similar to that of NO3•Mg-Al LDH, while it had a much lower cytotoxicity. The traditional methods for regenerating a culture medium by removing accumulated lactate to increase the cell density in large-scale cell culture and lower the costs, including electrolysis, cell modification, and modification of the culture medium’s composition, are complicated to operate and expensive. The adsorption method using HEPES•Mg-Al LDH presented in this study, instead, can be easily operated and has low costs. Thus, it is expected to be applied in actual cases for regenerating culture media.

Effect of Pleurotus ostreatus and Trametes versicolor on triclosan biodegradation and activity of laccase and manganese peroxidase enzymes

IntroductionTriclosan (TCS) is an extensively used antibacterial agent which has been frequently detected in different environmental compartments. Because of TCS inhibition effect on vast majority of bacterial species, it is important to explore fungal species and their involved enzymes in TCS biodegradation. The aim of this study was to compare the potential of two white rot fungi Pleurotus ostreatus and Trametes versicolor for TCS biodegradation through the whole cell culture of fungi in an aqueous culture medium. Additionally, the changes in ligninolytic enzyme activities and possible correlations and contributions of degradative enzymes during TCS biodegradation process were monitored. Material and methodsThis study was carried out using a factorial experiment with a completely randomized design in three replications. factorial design in The experimental factors included: two white rot fungi Pleurotus ostreatus and Trametes versicolor and uninoculated controls which were subjected to five levels of TCS concentrations (0, 5, 10, 20, 30 and 50 μg mL−1) to assess ligninolytic enzymatic activity during biodegradation of TCS. Samples were harvested periodically at three time intervals (4, 7 and 10 days). An AB SCIEX 3200 QTRAP LC-MS/MS system was used in order to analyze the biodegradation of TCS in liquid medium. ResultsResults suggested that the two white rot fungi responded differently when exposed to the different concentrations of TCS. In general, P. ostreatus exhibited more potential and ligninolytic enzymatic activity compared to T. versicolor. LC-MS/MS analyses also showed that P. ostreatus degraded TCS with higher efficiency compared to T. versicolor. In addition, almost all P. ostreatus biodegradation activity was completed within the first day of sampling. Contrasting, less efficient degradation was observed by T. versicolor, reaching around 88% of TCS biodegradation at concentration of 20 μg mL−1after 10 days. At higher TCS concentrations (≥30 μg mL−1), the growth of T. versicolor severely inhibited and led to a drop in enzymatic activity and biodegradation. Furthermore, laccase and manganese peroxidase (MnP) were determined as more involved enzymes which significantly correlated to TCS biodegradation by T. versicolor and P. ostreatus, respectively. ConclusionP. ostreatus might be considered as efficient fungus in biodegradation of high amount of TCS in environmental matrices. The results of the present study might provide insights for future investigations on potential of fungi for applications in bioaugmentation-based strategies to remove TCS from wastewater and activated sludge.

High potency of lipid conjugated TLR7 agonist requires nanoparticulate or liposomal formulation

Conjugation of small molecule agonists of Toll-like receptor 7 (TLR7) to proteins, lipids, or polymers is known to modulate potency, and the physical form or formulation of these conjugates is likely to have a major effect on their immunostimulatory activity. Here, we studied the effect of formulation on potency of a 1,2‑di‑(9Z‑octadecenoyl)‑sn‑glycero‑3‑phosphoethanolamine (DOPE) conjugated TLR7 agonist (DOPE-TLR7a) alongside assessing physical form using Dynamic Light Scattering (DLS), Nanosight Particle Tracking (NTA) analysis and Small Angle X-ray Scattering (SAXS). A very high potency of DOPE-TLR7a conjugate (EC50 around 9 nM) was observed either when prepared by direct dilution from DMSO or when formulated into 400–700 nm large multilamella liposomes containing dimethyldioctadecylammonium bromide salt (DDA) and DOPE. When prepared by dissolution in DMSO followed by dilution in aqueous culture medium, 93 ± 5 nm nanoparticles were formed. Without dilution from solution in DMSO, no nanoparticles were observed and no immunostimulatory activity could be detected without this formulation step. SAXS analysis of the conjugate after DMSO dissolution/water dilution revealed a lamellar order with a layer spacing of 68.7 Å, which correlates with arrangement in groups of 3 bilayers. The addition of another immunostimulatory glycolipid, trehalose‑6,6‑dibehenate (TDB), to DOPE:DDA liposomes gave no further increase in immunostimulatory activity beyond that provided by incorporating DOPE-TLR7a. Given the importance of nanoparticle or liposomal formulation for activity, we conclude that the major mechanism for increased potency when TLR7 agonists are conjugated to macromolecules is through alteration of physical form.

A hydrogel-coated membrane for highly efficient separation of microalgal bio-lipid

A cross-linked hydrogel-coated membrane was fabricated to achieve simple but highly efficient separation of bio-lipids directly from an aqueous microalgal culture medium. The membrane is composed of a stainless steel membrane coated conformally with a cross-linked hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), synthesized by a photo-initiated chemical vapor deposition (piCVD) process. The pHEMA-coated membrane has hydrophilicity and underwater-oleophobicity for efficient separation of a bio-lipid-in-hexane/water mixture by gravity. The conformal pHEMA film-coated membrane enables extremely high oil rejection performance with intrusion pressure of 6.1 kPa and water permeation flux of 6.5×103 L m-2 h-1, with excellent separation efficiency greater than 98.0%.

Precision Epitaxy for Aqueous 1D and 2D Poly(ε-caprolactone) Assemblies.

The fabrication of monodisperse nanostructures of highly controlled size and morphology with spatially distinct functional regions is a current area of high interest in materials science. Achieving this control directly in a biologically relevant solvent, without affecting cell viability, opens the door to a wide range of biomedical applications, yet this remains a significant challenge. Herein, we report the preparation of biocompatible and biodegradable poly(ε-caprolactone) 1D (cylindrical) and 2D (platelet) micelles in water and alcoholic solvents via crystallization-driven self-assembly. Using epitaxial growth in an alcoholic solvent, we show exquisite control over the dimensions and dispersity of these nanostructures, allowing access to uniform morphologies and predictable dimensions based on the unimer-to-seed ratio. Furthermore, for the first time, we report epitaxial growth in aqueous solvent, achieving precise control over 1D nanostructures in water, an essential feature for any relevant biological application. Exploiting this further, a strong, biocompatible and fluorescent hydrogel was obtained as a result of living epitaxial growth in aqueous solvent and cell culture medium. MC3T3 and A549 cells were successfully encapsulated, demonstrating high viability (>95% after 4 days) in these novel hydrogel materials.

Removal and metabolism of triclosan by three different microalgal species in aquatic environment

Triclosan, an antimicrobial additive widely used in personal care products, has caused the contamination of various aquatic environment. Biodegradation was proved to play a vital role in the treatment of triclosan in wastewater. However, there is limited information about the metabolic pathway. In this study, three common freshwater microalgae including Chlorella pyrenoidosa (C. pyrenoidosa), Desmodesmus sp., and Scenedesmus obliquus (S. obliquus) were applied to remove and biodegrade triclosan in aqueous culture medium. High removal rate up to 99.7% was observed during the treatment of 400μgL−1 triclosan by the three microalgae for 1day. The removal of triclosan attributed to cellular uptake by C. pyrenoidosa, and biotransformation by Desmodesmus sp. and S. obliquus. Simultaneously, triclosan metabolites resulted from hydroxylation, reductive dechlorination, or ether bond cleavage and their conjugates produced through glucosylation and/or methylation were detected in the biodegradation samples. Metabolic pathway of triclosan by algae were firstly proposed in this work, shedding light on the environmental fate of triclosan.

Physicochemical properties of ionic and non-ionic biocompatible hydrogels in water and cell culture conditions: Relation with type of morphologies of bovine fetal fibroblasts in contact with the surfaces

Cationic, anionic and non-ionic hydrogels having acrylamide polymer backbones were synthesized via free radical polymerization with N,N-methylenebisacrylamide (BIS) as crosslinker. The chemical structures of the hydrogels were characterized by Fourier Transform Infrared Spectroscopy (FTIR). Physicochemical properties such as swelling kinetic, maximum swelling capacity, volume phase transition temperature (VPTT) and wettability (static water contact angle) of hydrogels swollen in aqueous and cell culture medium, at room and cell culture temperatures were studied. In order to correlate the surface properties of the hydrogels and cellular adhesivity of bovine fetal fibroblasts (BFFs), cellular behaviour was analyzed by inverted fluorescence optical microscopy and atomic force microscopy (AFM). MTT assay demonstrated that the number of viable cells in contact with hydrogels does not significantly change in comparison to a control surface. Flattened and spindle-shaped cells and cell spheroids were the adopted morphologies during first days of culture on different hydrogels. Cell spheroids were easily obtained during the first 5days of culture in contact with PNIPAM-co-20%HMA (poly (N-isopropylacrylamide-co-20%N-acryloyl-tris-(hydroxymethyl)aminomethane)) hydrogel surface. After 15days of culture all hydrogels showed high adhesion and visual proliferation. According to obtained results, non-ionic and hydrophilic surfaces with moderated wettability induce the formation of BFFs cell spheroids. These hydrogel surfaces could be used in clinical and biochemical treatments at laboratory level to cell growth and will allow generating the base for future biotechnologic platform.

Assessment of cell viability and permeation enhancement in presence of lipid-based self-emulsifying drug delivery systems using Caco-2 cell model: Polysorbate 80 as the surfactant

PurposeLipid-based self-emulsifying drug delivery systems (SEDDS) are commonly used for solubilizing and enhancing oral bioavailability of poorly water-soluble drugs. However, their effects on viability of intestine epithelial cells and influence on membrane permeation are poorly understood. The present study was undertaken for safety assessment of lipid-based formulations containing medium-chain fatty acid esters as lipids and polysorbate 80 as the surfactant using the Caco-2 in vitro model. Any possible paracellular permeation enhancement through Caco-2 monolayers by the nontoxic formulations was also investigated. MethodsMixtures of monoglyceride (Capmul MCM EP or 708G) or propylene glycol monoester (Capmul PG-8 NF) of medium chain fatty acids with polysorbate 80, with and without the incorporation of a medium-chain triglyceride (Captex 355), were prepared. After suitable dilution with aqueous culture medium, the formulations were incubated with a series of Caco-2 cultures of different maturity. Cell viability and membrane integrity were assessed. Any effects of nontoxic formulations on the transport of the fluorescent dye, Lucifer yellow, through Caco-2 monolayers were also determined. ResultsFormulations containing 1:1 ratios of monoglyceride or propylene glycol monoester to triglyceride (30% polysorbate 80, 35% monoglyceride or monoester and 35% triglyceride) were best tolerated by Caco-2 cells. Increased maturity obtained through longer culture durations rendered Caco-2 cells greater tolerance towards lipid-based formulations, and maximum tolerance to lipid-based formulations was observed with Caco-2 monolayers after being cultured for 21–23days. Furthermore, extent of cell membrane rupture caused by lipid-surfactant mixtures correlated positively with levels of cytotoxicity, suggesting a potential underlying mechanism. Permeation studies using Caco-2 monolayer model revealed that certain formulations significantly enhanced paracellular transport activities. ConclusionsLipid-based SEDDS containing mixtures of monoglyceride (or monoester) and triglyceride of medium chain fatty acids formed fine microemulsions and were significantly less toxic than other formulations. Fully differentiated Caco-2 monolayer was more resistant to lipid-surfactant mixtures than less mature cultures. Certain formulations were also capable of enhancing paracellular permeation.

Kinetic modelling of a diesel-polluted clayey soil bioremediation process

A mathematical model is proposed to describe a diesel-polluted clayey soil bioremediation process. The reaction system under study was considered a completely mixed closed batch reactor, which initially contacted a soil matrix polluted with diesel hydrocarbons, an aqueous liquid-specific culture medium and a microbial inoculation. The model coupled the mass transfer phenomena and the distribution of hydrocarbons among four phases (solid, S; water, A; non-aqueous liquid, NAPL; and air, V) with Monod kinetics. In the first step, the model simulating abiotic conditions was used to estimate only the mass transfer coefficients. In the second step, the model including both mass transfer and biodegradation phenomena was used to estimate the biological kinetic and stoichiometric parameters. In both situations, the model predictions were validated with experimental data that corresponded to previous research by the same authors. A correct fit between the model predictions and the experimental data was observed because the modelling curves captured the major trends for the diesel distribution in each phase. The model parameters were compared to different previously reported values found in the literature. Pearson correlation coefficients were used to show the reproducibility level of the model.