Luis Jesús Villarreal-Gómez

Antibacterial and anticancer activity of seaweeds and bacteria associated with their surface

Marine algae and bacteria are an inexhaustible source of chemical compounds that produce a wide variety of biologically active secondary metabolites. Marine ...

Electrospinning as a powerful technique for biomedical applications: a critically selected survey

Abstract Nowadays, electrospinning has become one of the most versatile, easy, and cost-effective techniques to engineer advanced materials used for many applications, especially in the biomedical and environmental areas. Like the numerous patents around the world, the increasing number of papers witnesses the huge potential of this simple process, and many companies have been emerged during the last years to exploit its innumerable applications. This article presents a critically selected overview of polymers that can be used to produce nanofibers, along with the biomedical applications of the resulting electrospun scaffolds. We have focused on about seven natural and synthetic polymers, but many more can be found in the literature, either as their pristine state or as composites with ceramics, metals, and other polymers. The description of some strategies for nanofiber production, and the characterization used to evaluate their optimization, has been discussed. Finally, several polymers have been recognized as highlights for future work.

Bioactive Compounds from Bacteria Associated to Marine Algae

Since ancient times, humans have sought to satisfy their needs, one of which is, without a doubt, to stay alive. The fear of getting sick and dying, led man to study the organisms that surround him, discovering that the chemicals compounds present in some of them could be beneficial for treating illness. Thus; began the chemistry of the natural products; biotechnology area for human welfare. Several of these organisms produce secondary metabolites, which are part of a wide variety of natural compounds used by humans to combat diseases. Secondary metabolites are defined as organic compounds formed as bio products in organisms, not directly related to growth, development and normal reproduction of thereof. Some examples are fibers (cotton, silk, wool); fuels (oil and natural gas), and medicines (antibiotics, hormones, vaccines).

Biocompatibility Evaluation of Electrospun Scaffolds of Poly (L-Lactide) with Pure and Grafted Hydroxyapatite

The objective of this work was to evaluate the biocompat- ibility of scaffolds of poly(L-lactide) with pure and grafted hydroxyap- atite, at various concentrations of reinforcement. The biocompatibility tests were carried out in vivo in Wistar rats by implanting the material into the subcutaneous and muscle tissues from 1 to 14 weeks and evaluating the surrounding tissue stained with hematoxylin-eosin. For in vitro assays, MTT and neutral red assay were used to evaluate any cytotoxicity in Mioblast Muscle C2C12 Cells (ATCC® CRL-1772™) and Bovine Coronary Artery Endothelial Cells (BCAEC); Escherichia coli and Staphylococcus aureus were used to evaluate bacterial adhe- sion. All variants of scaffolds provoked a mild inflammatory response, without showing necrosis. No evidence of cytotoxicity was presented in cell viability tests and good bacterial cell adhesion was visualized for all of the materials studied.

Study of nanofiber scaffolds of PAA, PAA/CS, and PAA/ALG for its potential use in biotechnological applications

ABSTRACT In recent times, electrospun nanofibers have been widely studied from several biotechnological approaches; in this work, poly(acrylic acid) (PAA) solutions mixed with chitosan and alginate were electrospun and characterized to determine the behavior of these fibers when used in combination with bacteria, different samples were incubated with the bacterial strains: Streptomyces spp., Micromonospora spp., and Escherichia coli and a OD600 test was performed. The formation of nanofibers via electrospinning and the physicochemical properties of the obtained fibers were evaluated. Results showed that the presence of chitosan enhanced the thermal stability of PAA, since PAA/alginate fibers lost 5% of their mass at 41°C, whereas PAA/chitosan lost this amount at around 125°C. The fibers demonstrated suitable characteristics to be used as a bacteria bioreactor. GRAPHICAL ABSTRACT

Polymeric advanced delivery systems for antineoplasic drugs: doxorubicin and 5-fluorouracil

Abstract Conventional pharmaceuticals generally display the inability to transport active ingredients directly to specific regions of the body, amongst some of their main limitations. The distribution of the drugs in the circulatory system may lead to undesired toxicity, and therefore, adverse reactions. To address this situation, a selective transport of drugs is required, that is, releasing drugs specifically to the site of action in appropriate concentrations and in the right time. To achieve this goal, it is necessary to develop delivery systems that respond to several features, such as low toxicity, optimum properties for the transport and release of the drug, as well as a long half-life in the body. This feature paper critically provides an overview of different strategies of controlled drug release for two model antineoplasic drugs, i.e. doxorubicin (DOX) and 5-fluorouracil (5-FU). Any of the presented strategies for drug release possess advantages and disadvantages, and the selection of the strategy used will depend on the targeted tissue and nature of the drug.

Fabrication of porous polymeric structures using a simple sonication technique for tissue engineering

Abstract Porous polymeric scaffolds have been applied successfully in the biomedical field. This work explores the use of an ultrasonic probe to generate cavitation in a polymeric solution, thus producing pores in the polymeric scaffolds. Porous polymeric structures with average pore sizes ranging from 5 to 63 μm and porosity of 6–44% were fabricated by a process consisting of sonication, flash freezing, and lyophilization of poly(lactic-co-glycolic acid) (PLGA), gelatin (GEL), chitosan (CS) and poly(vinyl alcohol) (PVAL) solutions. Pore structure was characterized by scanning electron microscopy (SEM) and image analysis software. The infrared spectra were analyzed before and after the fabrication process to observe any change in the chemical structure of the polymers. A water absorption test indicated the susceptibility of the samples to retain water in their structure. TGA results showed that GEL experienced degradation at 225°C, CS had a decomposition peak at 280°C, the thermal decomposition of PLGA occurred at 375°C, and PVAL showed two degradation regions. The DSC analysis showed that the glass transition temperature (Tg) of GEL, CS, PLGA and PVAL occurred at 70°C, 80°C, 60°C and 70°C, respectively. The fabricated porous structures demonstrated similar physical characteristics to those found in bone and cartilage.

Air, Water and Soil: Resources for Drug Discovery

Drug discovery is the process by which new candidate drugs are discovered. The chemical compounds that are present in plants and animals have been an important source of new bioactive compounds. Also, we can found organisms that live in air, water and soil that we don`t see, but posses a great variety of chemical that we can use to create new medicines. Bioactive compounds offer an enormous diversity of chemical structures with strong biolog‐ ic effect; this is one of the reasons why natural products research cannot be replaced by syn‐ thesis chemistry as a source for new bioactive compounds. Actually, more than the half of currently used medicines came from natural sources or are related to them, specifically in the situation of anticancer drugs that more than 60% belongs from nature [1].