The novel albumin–chitosan core–shell nanoparticles for gene delivery: preparation, optimization and cell uptake investigation

Natural polymers and proteins such as chitosan (CS) and albumin (Alb) have recently attracted much attention both in drug delivery and gene delivery. The underlying rationale is their unique properties such as biodegradability, biocompatibility and controlled release. This study aimed to prepare novel albumin–chitosan–DNA (Alb-CS-DNA) core–shell nanoparticles as a plasmid delivery system and find the best conditions for their preparation. Phase separation method and ionic interaction were used for preparation of Alb nanoparticles and Alb-CS-DNA core–shell nanoparticles, respectively. The effects of three important independent variables (1) CS/Alb mass ratio, (2) the ratios of moles of the amine groups of cationic polymers to those of the phosphate groups of DNA (N/P ratio), and (3) Alb concentration, on the nanoparticle size and loading efficiency of the plasmid were investigated and optimized through Box–Behnken design of response surface methodology (RSM). The optimum conditions were found to be CS/Alb mass ratio = 3, N/P ratio = 8.24 and Alb concentration = 0.1 mg/mL. The most critical factors for the size of nanoparticles and loading efficiency were Alb concentration and N/P ratio. The optimized nanoparticles had an average size of 176 ± 3.4 nm and loading efficiency of 80 ± 3.9 %. Cytotoxicity experiments demonstrated that the prepared nanoparticles were not toxic. The high cellular uptake of nanoparticles (~85 %) was shown by flow cytometry and fluorescent microscopy.Tarbiat Modares UniversityUnited States. National Institutes of Health (Grant R01A1050875

Moving from a Product-Based Economy to a Service-Based Economy for a More Sustainable Future

Traditionally, economic growth and prosperity have been linked with the availability, production and distribution of tangible goods as well as the ability of consumers to acquire such goods. Early evidence regarding this connection dates back to Adam Smith's Wealth of Nations (1776), in which any activity not resulting in the production of a tangible good is characterized as unproductive of any value." Since then, this coupling of economic value and material production has been prevalent in both developed and developing economies throughout the world. One unintended consequence of this coupling has been the exponential increase in the amount of solid waste being generated. The reason is that any production and consumption of material goods eventually generates the equivalent amount of (or even more) waste. Exacerbating this problem is the fact that, with today's manufacturing and supply chain management technologies, it has become cheaper to dispose and replace most products rather than to repair and reuse them. This has given rise to what some call a disposable society." To put things in perspective: In 2012 households in the U.K. generated approximately 22 thousand tons of waste, which amounted to 411 kg of waste generated per person (Department for Environment, Food & Rural Affairs, 2015). During the same time period, households in the U.S. generated 251 million tons of waste, which is equivalent to a person generating approximately 2 kg of waste every day (U.S. Environmental Protection Agency, 2012). Out of these 251 million tons of total waste generated, approximately 20% of the discarded items were categorized as durable goods. The disposal of durable goods is particularly worrisome because they are typically produced using material from non- renewable resources such as iron, minerals, and petroleum-based raw materials

A textile platform using mechanically reinforced hydrogel fibres towards engineering tendon niche

INTRODUCTION: Tendon injuries can result from tendon overuse or trauma, resulting in substantial pain and disability. Given that natural or surgical repair of tendons lead to a poor outcome in terms of mechanical properties and functionality, there is a great need for tissue engineering strategies. Textile platforms enable the generation of biomimetic constructs [1]. Therefore, the main goal of this study is the development of cell-laden hybrid hydrogel fibers reinforced with a mechanically robust core fiber and their assembly into braided constructs towards replicating tendon mechanical properties and architecture. METHODS: To fabricate mechanically reinforced hydrogel fibres, a commercially available suture was coated using a cell-hydrogel mixture of methacryloyl gelatine (GelMA) and alginate. Composite fibres (CFs) were obtained by ionic crosslinking of alginate followed by photocrosslinking of GelMA. CFs were assembled using braiding technique and the mechanical properties of single fibres and braided constructs were evaluated. Different cells were encapsulated in the hydrogel layer, including MC-3T3, mesenchymal stem cells (MSCs) and human tendon-derived cells (TDCs). Cell viability and metabolic activity were evaluated by LIVE/DEAD staining and presto blue assay of metabolic activity. The expression of tendon-related markers and matrix deposition were also investigated. RESULTS: CFs were fabricated with a GelMA:alginate hydrogel layer and using multifilament twisted cotton or biodegradable suturing threads. The biocompatibility of this system was evaluated on encapsulated cells (Fig.1a). Cells (MC-3T3, MSCs and TDCs) were homogeneously distributed along the hydrogel layer, being viable up to 14 days in culture. In addition, TDCs were spreading inside the hydrogel after less than 48 h. Moreover, to further improve the mechanical properties of CFs, braided constructs were generated (Fig. 1b). Braiding CFs together enhanced their tensile strength and the process did not affect the viability of encapsulated cells.DISCUSSION & CONCLUSIONS: CFs were generated with a load bearing core and a hydrogel layer towards mimicking both mechanical properties and the matrix-rich microenvironment of tendon tissue. Accordingly, cell behaviour can be further modulated by modifying the hydrogel composition or, ultimately, through the addition of bioactive cues. Finally, braiding CFs together allows tuning the mechanical properties of developed constructs to match those of native tendon tissues.Fundação para a Ciência e a Tecnologia in the framework of FCT-POPH-FSE, the PhD grant SFRH/BD/96593/2013 of R.C-

Magnetism and its microscopic origin in iron-based high-temperature superconductors

High-temperature superconductivity in the iron-based materials emerges from, or sometimes coexists with, their metallic or insulating parent compound states. This is surprising since these undoped states display dramatically different antiferromagnetic (AF) spin arrangements and N$\rm \acute{e}$el temperatures. Although there is general consensus that magnetic interactions are important for superconductivity, much is still unknown concerning the microscopic origin of the magnetic states. In this review, progress in this area is summarized, focusing on recent experimental and theoretical results and discussing their microscopic implications. It is concluded that the parent compounds are in a state that is more complex than implied by a simple Fermi surface nesting scenario, and a dual description including both itinerant and localized degrees of freedom is needed to properly describe these fascinating materials.Comment: 14 pages, 4 figures, Review article, accepted for publication in Nature Physic

Mining conflicts around the world: Common grounds from an Environmental Justice perspective

Abstract. This report aims at exploring contemporary mining conflicts in the context of the sustainable development and environmental justice movement. This is done based on 24 real case studies from 18 different countries which are described by local activists and scholars. While 17 of the reported cases focus on conflicts related to metal mining (e.g. gold, silver, copper, zinc, and lead), four address uranium mining and one refers to coal mining. As an example of a new frontier in the industry, a sand mining conflict from India is also reported. All of these cases are directly chosen and reported, either in factsheet or in-depth study format, by EJOs, as part of a knowledge sharing activity well-established in EJOLT between EJOs and the academic community. Although the cases covered here are all quite unique and diverse in terms of type of conflict and geographical setting, they all share a common frame of analysis. First, the project and type of conflict are characterized in a nutshell, with some basic factual background that describe the companies involved, and the communities and locations affected. The roots of the conflicts are explored next, as well as relevant socioeconomic, cultural, health, and ecological impacts and related community claims. Where relevant, means of resistance are also specified with their influence on the project and/or the outcome of the conflict. The report then offers a synthesis of the described mining cases, review their commonalities, link gained insights with research needs and discuss some policy recommendations that might follow from this analysis. Despite its limitations, compiling such a diverse set of mining conflicts that builds on EJO knowledge promotes mutual learning and collaboration among stakeholders, EJOs and academia, which is one of the key objectives of EJOLT

Antiferromagnetic spintronics

Antiferromagnetic materials are magnetic inside, however, the direction of their ordered microscopic moments alternates between individual atomic sites. The resulting zero net magnetic moment makes magnetism in antiferromagnets invisible on the outside. It also implies that if information was stored in antiferromagnetic moments it would be insensitive to disturbing external magnetic fields, and the antiferromagnetic element would not affect magnetically its neighbors no matter how densely the elements were arranged in a device. The intrinsic high frequencies of antiferromagnetic dynamics represent another property that makes antiferromagnets distinct from ferromagnets. The outstanding question is how to efficiently manipulate and detect the magnetic state of an antiferromagnet. In this article we give an overview of recent works addressing this question. We also review studies looking at merits of antiferromagnetic spintronics from a more general perspective of spin-ransport, magnetization dynamics, and materials research, and give a brief outlook of future research and applications of antiferromagnetic spintronics.Comment: 13 pages, 7 figure

Antimicrobial activity of apple cider vinegar against Escherichia coli, Staphylococcus aureus and Candida albicans; downregulating cytokine and microbial protein expression

The global escalation in antibiotic resistance cases means alternative antimicrobials are essential. The aim of this study was to investigate the antimicrobial capacity of apple cider vinegar (ACV) against E. coli, S. aureus and C. albicans. The minimum dilution of ACV required for growth inhibition varied for each microbial species. For C. albicans, a 1/2 ACV had the strongest effect, S. aureus, a 1/25 dilution ACV was required, whereas for E-coli cultures, a 1/50 ACV dilution was required (p < 0.05). Monocyte co-culture with microbes alongside ACV resulted in dose dependent downregulation of inflammatory cytokines (TNFα, IL-6). Results are expressed as percentage decreases in cytokine secretion comparing ACV treated with non-ACV treated monocytes cultured with E-coli (TNFα, 99.2%; IL-6, 98%), S. aureus (TNFα, 90%; IL-6, 83%) and C. albicans (TNFα, 83.3%; IL-6, 90.1%) respectively. Proteomic analyses of microbes demonstrated that ACV impaired cell integrity, organelles and protein expression. ACV treatment resulted in an absence in expression of DNA starvation protein, citrate synthase, isocitrate and malate dehydrogenases in E-coli; chaperone protein DNak and ftsz in S. aureus and pyruvate kinase, 6-phosphogluconate dehydrogenase, fructose bisphosphate were among the enzymes absent in C.albican cultures. The results demonstrate ACV has multiple antimicrobial potential with clinical therapeutic implications