Eva M. Martín del Valle

Immobilization of Mesenchymal Stem Cells and Monocytes in Biocompatible Microcapsules to Cell Therapy

The aim of cell therapy is to replace, repair, or enhance the function of damaged tissues or organs. Several factors complicate the development of cellular therapies. Of primary importance is protection of the implanted cells from the hostapos;s immune system. Cells are encapsulated in selectively semipermeable and biocompatible membranes that block entry of immune mediators but allow outward diffusion of active molecules produced by the cells. The immobilization of mesenchymal stem cells and monocytes, in micrometric (30–60 μm) alginate‐barium microcapsules based on atomization processes, has been achieved successfully. This size is necessary to the administration of microcapsules via injection (Hamilton syringe with a needle size of 100 μm) and aerosol. Microencapsulated cells survive at least 2 weeks after preparation in vitro.

Rheological characterization of commercial highly viscous alginate solutions in shear and extensional flows

The rheological properties of sodium alginate in salt-free solutions were studied by steady shear, dynamic oscillatory and extensional measurements. This biopolymer consists of mannuronic and guluronic acid residues that give a polyelectrolyte character. We applied the scaling theories and checked their accordance with polyelectrolyte behaviour for low concentrations with a shift to neutral polymer behaviour at larger concentrations. This nature was supported by the effect of the concentration on the specific viscosity, the relaxation times from steady shear and the longest relaxation times from small amplitude oscillatory shear (SAOS) measurements. To analyze the extensional behaviour of the samples, we conducted a study of dimensionless numbers and time scales where filament thinning driven by viscous, capillary or elastic forces is at play. We conclude that an exponential filament thinning followed by breakup results in the best regimes that describe the experimental data. Besides, the data pointed out that alginate in salt-free concentrated solutions shows strain thinning of the extensional viscosity and chain rigidity, behaviours that cannot be inferred from the shear rheometry.

Effect of nitrogen source on growth and lipid accumulation in Scenedesmus abundans and Chlorella ellipsoidea

Discovering microalgae strains containing a high lipid yield and adequate fatty acid composition is becoming a crucial fact in algae-oil factories. In this study, two unknown strains, named Scenedesmus abundans and Chlorella ellipsoidea, have been tested for their response to different nitrogen sources, in order to determine its influence in the production of lipids. For S. abundans, autotrophic culture with ammonium nitrate offers the maximum lipid yield, obtaining up to 3.55 mg L(-1) d(-1). For C. ellipsoidea, heterotrophic culture with ammonium nitrate has been shown to be the best condition, reaching a lipid production of 9.27 mg L(-1) d(-1). Moreover, fatty acid composition obtained from these cultures meets international biodiesel standards with an important amount of C18:1, achieving 70% of total fatty acids and thus representing a potential use of these two strains at an industrial scale.

Chemical engineering : trends and developments

List of Contributors. Preface. 1. The Art and Science of Upscaling (Pedro E. Arce, Michel Quintard and Stephen Whitaker). 2. Solubility of Gases in Polymeric Membranes (M. Giacinti Baschetti, M. G. De Angelis, F. Doghieri, G. C. Sarti). 3. Small Peptide Ligands for Affinity Separations of Biological Molecules (Guangquan Wang, Jeffrey R. Salm, Patrick V. Gurgel and Ruben G. Carbonell). 4. Bioprocess Scale-up: SMB as a promising technique for industrial separations using IMA (E.M. Del Valle, R. Gutierrez and M.A. Galan) 5. Opportunities in catalytic reaction engineering. Examples of heterogeneous catalysis in water remediation and preferential CO oxidation (J. Levec). 6. Design and analysis of homogeneous and heterogeneous photoreactors (A.E. Cassano and O.M. Alfano). 7. Development of nano-structured micro-porous materials and their application in bioprocess - chemical process intensification and tissue engineering (G. Akay, M.A. Bokhari, V.J. Byron, and M. Dogru). 8. The encapsulation art: scale-up and applications (M.A. Galan, C.A. Ruiz and E.M. Del Valle). 9. Continuous processes for fine coatings and membranes (Skip Scriven). 10. Langmuir-blodgett films: a window to nanotechnology (M.E. Diaz and R. Cerro). 11. Advances in process integration and supply change management (Ignacio Grossman). 12. Integration of Process Systems Engineering and Business Decision Making Tools: Financial Risk Management and Other Emerging Procedures (Miguel Bagajewicz). Index.

Microalgae Technology: A Patent Survey

Abstract For a long time now, it is known that an infinite number of compounds can be obtained from microalgae due to their promising composition. This fact is used by several companies to produce at medium-scale different high value products such as carotenoids. Furthermore, this last decade research in this topic has significantly increased given the potential solution these microorganisms present to meet World environmental agreements regarding CO2 emissions. However, the culture of large-scale microalgae in order to obtain products which are required in huge quantities (e.g., oil for manufacturing biodiesel) and at the same time removing pollutants appeared as a difficult task due to the great number of variables that must be taken into account. The photobioreactor design for cultivating the microalgae is perhaps the most important task, but there are other bottle-necks, such as the harvesting system, cleaning system, control system, the chosen microalgae, and the extraction of products from the microalgae. This review focuses on around 200 patents covering microalgae technology, from different photobioreactors designs to microalgae applications, in order to construct a perfect large-scale facility removing CO2 in the process.

Development of a nanoparticle system based on a fructose polymer: Stability and drug release studies

New drug delivery systems (DDSs) with levan or its carboxymethylated form, as carriers, and 5-fluorouracil as a drug, are produced in this work. Levan is obtained after cultivating A. nectaris and polymer nanoparticles are created in water by a self-assembled process. The effect of pH and the ionic strength on polymer nanoparticles aggregation is studied. Basic pHs produces a particle size between 300 and 400nm with a Z-potential around -20mV because a basic medium promotes repulsion forces. DDSs of 300-400nm and a Z-potential about -25mV are prepared by taking advantage of the amphiphilic properties of the levan. The drug is bound to either levan or carboxymethyllevan surfaces by electrostatic interactions, obtaining the best results at basic pHs. 45-70% of the drug is released from the levan in 23h depending on the pH preparation, whereas only a low percentage of the drug is released from the carboxymethyllevan.

Understanding and optimizing the addition of phytohormones in the culture of microalgae for lipid production.

Some studies have described the use of phytohormones in microalgal culture for the production of biodiesel or selected fatty acids. However, no study has determined the amount of phytohormones that maximizes lipid yield. We determined the optimal concentration of auxins and gibberellins (which is between 40 and 60 μM) in two strains (Scenedemus abundans and Chlorella ellipsoidea) suitable for biodiesel production. More than 3‐fold increment was reached with S. abundans and near 7‐fold increment with C. ellipsoidea. Furthermore, this work suggests that the improved growth of the microalgae in the presence of the phytohormones was due to a reduction in the level of reactive oxygen species (ROS) in the cells. An economic analysis showed that, due to its low cost, auxin offers a positive cost‐benefit balance and therefore could be used at large scale.

Survey of supercritical fluid techniques for producing drug delivery systems for a potential use in cancer therapy

Abstract Standard drug delivery systems for cancer treatment usually comprise a device with a specific size and shape (depending on the type of cancer that has to be treated), which is composed by a biodegradable compound with a chemotherapeutic entrapped within it. This device should have a molecule (mainly a protein) bound to its surface to target only cancer cells. On the contrary, supercritical fluids (SCF) have been widely used in the pharmaceutical industry for creating drug delivery systems or for extracting drugs from natural sources. This review explains the potential of SCFs for cancer therapies by studying the current uses of the different high-pressure processes that can be useful for this medical treatment, such as the development of new drug delivery systems (with their drug release) or the extraction of chemotherapeutics from a vegetal matrix.

Preparation and preliminary evaluation of alginate crosslinked microcapsules as potential drug delivery system (DDS) for human lung cancer therapy

Human lung cancer is the main cancer cause of death in men and the third cancer cause in women. As it is well-known, current antitumor treatments involve chemotherapy which mostly entails aggressive side effects. This study describes a drug delivery targeted strategy based in bioconjugated polymeric microcapsules with a size of around 30 μm. Alginate microcapsules, produced using a fan-jet nozzle, are used due to its biodegradability and biocompatibility and will be tested in vitro. Firstly, microparticles are prepared by ionic gelation of an alginate core sprayed on a barium chloride solution. Afterwards, epidermal growth factor is attached onto the surface of these microcapsules to specifically target non-small lung cancer cells (NSCLC). This bioconjugation is performed together with an anticancer agent, cisplatin. The in vitro studies of cytotoxicity has been tested with H460 lung cancer cell line and with controls on systems loaded with free drugs. In vitro validation tests were carried out in Petri plates and the cells viability were checked by MTT assay. These experiments showed that drug delivery treatment allows a faster mortality in H460 lung cancer cell plates. To sum up, this study reports the development of an advanced drug delivery system that improves the specificity issue on drug delivery in addition and in vitro confirmation in cell mediums containing NSCLC.

Cytotoxicity of paramagnetic cations—Loaded polydopamine nanoparticles

Polydopamine (PD) is a synthetic melanin pigment of great importance in biomedicine, where its affinity for metallic cations, especially paramagnetic ions, has sparked interest in its use in the development of magnetic resonance imaging (MRI) contrast agents. In this work, we report the cytotoxicity of metal-enriched PD nanoparticles on NIH3T3, a healthy cell line and BT474, a breast cancer cell line. Remarkably, it was found that the metal- enriched PD particles (Mn+ = Fe3+, Fe2+ and Cu2+) were highly cytotoxic to the breast cancer cells, even after 24 h of treatment. Although, this effect was not selective systems, since an acute cytotoxic effect was also observed on the healthy cell line, this system can be considered as starting point for designing advanced antineoplastic agents.