Stacking up: a new approach for cell culture studies

Traditional cell culture relies mostly on flat plastic surfaces, such as Petri dishes and multiwell plates. These commercial surfaces provide limited flexibility for experimental design. In contrast, cell biology increasingly demands surface customisation, functionalisation, and cell monitoring in order to obtain data that is relevant in vivo. The development of research areas such as microfluidics and electrochemical detection methods greatly promoted the customised design of cell culture platforms. However, the challenges for mass production and material limitations prevent their widespread usage and commercialisation. This article presents a new cell culture platform based on stacks of a transparent flexible printable substrate. The arrangement introduces multi-layered stacks for possible manipulation and access to the cells. The platform is highly compatible with current technologies, such as colorimetric imaging and fluorescence microscopy. In addition, it can potentially integrate, e.g., biomaterials, patterning, microfluidics, electrochemical detection and other techniques to influence, monitor, and assess cell behaviour in a multitude of different settings. More importantly, the platform is a low-cost alternative customisable through functional printing and coating technologies. The device shown in this manuscript represents a prototype for more sophisticated variations that will expand the relevance of in vitro studies in cell biology

Efficacy Of Natural Plant Extracts In Antimicrobial Packaging Systems

Antimicrobial plant extracts used in food packaging provide a healthy packaging alternatives. They contain aromatic and phenolic compounds that are responsible for their antibacterial properties. In this study, we report the antibacterial effects of extracts obtained from sea buckthorn (Hippophaë rhamnoides L.) leaves, and inner bark of pine trees (Pinus silvestris) that were applied as coatings on paper suitable for packaging application. Extracts from sea buckthorn leaves exhibited antibacterial effect both as a solvent extract and as a coating on paper against Pseudomonas aeruginosa as test bacteria. However, coatings of pine bark extract did not exhibit antibacterial effect as coatings even though the solvent extracts exhibited antibacterial effects. Staphylococcus aureus demonstrated resistance towards both plant extracts after they had been applied as coatings on paper for packaging

Antimicrobial characterization of silver nanoparticle-coated surfaces by “touch test” method

Abstract: Bacterial infections, especially by antimicrobial resistant (AMR) bacteria, are an increasing problem worldwide. AMR is especially a problem with health care-associated infections due to bacteria in hospital environments being easily transferred from patient to patient and from patient to environment, and thus, solutions to prevent bacterial transmission are needed. Hand washing is an effective tool for preventing bacterial infections, but other approaches such as nanoparticle-coated surfaces are also needed. In the current study, direct and indirect liquid flame spray (LFS) method was used to produce silver nanoparticle-coated surfaces. The antimicrobial properties of these nanoparticle surfaces were evaluated with the “touch test” method against Escherichia coli and Staphylococcus aureus. It was shown in this study that in glass samples one silver nanoparticle-coating cycle can inhibit E. coli growth, whereas at least two coating cycles were needed to inhibit S. aureus growth. Silver nanoparticle-coated polyethylene (PE) and PE terephthalate samples did not inhibit bacterial growth as effectively as glass samples: three nanoparticle-coating cycles were needed to inhibit E. coli growth, and more than 30 coating cycles were needed until S. aureus growth was inhibited. To conclude, with the LFS method, it is possible to produce nanostructured large-area antibacterial surfaces which show antibacterial effect against clinically relevant pathogens. Results indicate that the use of silver nanoparticle surfaces in hospital environments could prevent health care-associated infections in vivo.</p

Characterization of flame coated nanoparticle surfaces with antibacterial properties and the heat-induced embedding in thermoplastic-coated paper

Silver nanoparticles deposited on surfaces can provide an antibacterial effect with potential uses in, for example, health-care settings. However, release of nanoparticles and their potential exposure to the environment is of concern. The current work demonstrates a continuous synthesis that simultaneously deposits silver nanoparticles onto plastic coated paper surface by utilizing the liquid flame spray (LFS) aerosol process. Heat from LFS is used to soften the thermoplastic paper surface, which enables partial and full embedding of the nanoparticles, thereby improving adhesion. The embedding is confirmed with atomic force and scanning electron microscopy, and the deposited silver amounts are quantified with X-ray photoelectron spectroscopy. The results suggest that embedding was more effective in PE-coated paper samples due to the lower glass transition temperature when compared to PET-coated paper samples. The antibacterial properties of the surfaces against E. coli and S. aureus were maintained and confirmed with a previously developed 'Touch-Test Method: The LFS process has the potential to be used for large-scale manufacturing of antibacterial surfaces with improved nanoparticle adhesion on appropriately chosen thermoplastic surfaces

Los sentidos de la manifestación: Prácticas, relatos e imágenes entorno de la "Masacre del 26 de Junio en Avellaneda"

The mobilization of the urban poor within the frame of piqueteros' organizations in the suburbs of Buenos Aires has been matter of two different approaches. On the one hand an ethnographic focus, that explores the associative networks interweaved by impoverished organizations and neighbors; and a sociological glance, that concentrates on the conditions and forms of collective construction of the organizations. Nevertheless, less attention has been paid to the public and interactive construction of the events of social protest that involve the piqueteros' organizations of this urban area. Building on this void, we seek to put forward a preliminary exploration of some dimensions of that public construction in the case of the socalled 'Massacre of June 26th in Avellaneda'. Understanding these events as a manifestation, that is to say: 'corporal and discursive interventions in the public sphere involving political content [in a broad sense of the term] and resorting to the tools of street mobilization', we seek both to reconstruct a narrative of those events and to develop a description and analysis of what several involved actors maintained that 'one had to think' about what had actually happenedLa movilización de los pobres urbanos en el marco de las organizaciones piqueteras del conurbano bonaerense ha sido materia de un doble enfoque. Una mirada de perfil etnográfico, que profundiza en las tramas asociativas que entretejen organizaciones y vecinos empobrecidos; y una mirada sociológica, que se concentra en las condiciones y las formas de construcción de las organizaciones. Sin embargo, menos atención se ha prestado ala construcción pública e interactiva de los eventos de protesta social que involucran a las organizaciones piqueteras de esta área urbana. Situándonos en este hueco nos proponemos avanzar en una exploración preliminar de algunas dimensiones de esa construcción pública en el caso de la denominada "Masacre del 26 de Junio en Avellaneda". Tomando estos eventos como manifestación, es decir : "intervenciones corporales y discursivas de contenido político [en el sentido amplio del término] en el espacio público recurriendo a los instrumentos de la movilización callejera', nos interesa tanto reconstruir un relato de lo que ocurrió en ese entonces como hacer una descripción y análisis de lo que diversos actores involucrados sostuvieron que "debía pensarse' de aquello que ocurri

A modified Stokesian dynamics method for mineral suspensions

A 3-dimensional modified Stokesian dynamics-based technique for simulating mineral particle suspensions is presented. Stokesian dynamics is a mesh free particle approach, which resembles the discrete element method. It includes hydrodynamic interactions and other interparticle forces. Expressions for the hydrodynamic interactions were modified based on results from finite element (FE) calculation. The modifications allow for broader particle size distributions than captured by traditional analytical expressions describing hydrodynamic interactions. In addition, models are presented for colloidal interactions, steric repulsion caused by polymer adsorbed onto mineral particles and the Brownian motion. These models expand the applicability down to μm and nm size particles. Comparison between governing forces can be made by generation of dimensionless expressions such as the particle Reynolds and Peclét numbers. Numerical simulations performed using this technique enable the study of microscopic scale mechanisms and the characterisation of particle systems. This allows for appreciation of microstructure development in time and the prediction of macroscopic level properties of particle suspensions and consolidating systems. This paper reports on both model development and results utilising the above-described approach. In conclusion, the method is put into context by discussion of the applicability of the method in various wet-state mineral processing applications.Godkänd; 2011; 20111010 (ysko