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Gaining a greater understanding of the blood-brain barrier (BBB) is critical for improvement in drug delivery, understanding pathologies that compromise the BBB, and developing therapies to protect the BBB. In vitro human tissue models are valuable tools for studying these issues. The standard in vitro BBB models use commercially available cell culture inserts to generate bilayer co-cultures of astrocytes and endothelial cells (EC). Electrospinning can be used to produce customized cell culture substrates with optimized material composition and mechanical properties with advantages over off-the-shelf materials. Electrospun gelatin is an ideal cell culture substrate because it is a natural polymer that can aid cell attachment and be modified and degraded by cells. Here, we have developed a method to produce cell culture inserts with electrospun gelatin 'biopaper' membranes. The electrospun fiber diameter and cross-linking method were optimized for the growth of primary human endothelial cell and primary human astrocyte bilayer co-cultures to model human BBB tissue. BBB co-cultures on biopaper were characterized via cell morphology, trans-endothelial electrical resistance (TEER), and permeability to FITC-labeled dextran and compared to BBB co-cultures on standard cell culture inserts. Over longer culture periods (up to 21 days), cultures on the optimized electrospun gelatin biopapers were found to have improved TEER, decreased permeability, and permitted a smaller separation between co-cultured cells when compared to standard PET inserts. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 901-909, 2016. [ABSTRACT FROM AUTHOR]

Traditional high throughput methods for isolating microorganisms from environmental samples such as soil or sediment require pre-processing steps to remove the living species from their solid-phase microniche, creating a liquid-phase sample. This process destroys near-neighbor relationships that could be crucial to culturing and studying the microorganisms to be isolated., An automated, high throughput method is described here that isolates pure microbial cultures and spatially related microbial consortia directly from a solid-phase complex environmental sample. By using an orifice-free printing mechanism, Biological Laser Printing (Bio LP) enabled single-step isolation of viable environmental microorganisms directly from soil. Soil was spread onto a titania-coated quartz plate prior to initiating printing of soil micro-particles with focused ultraviolet laser pulses., Tunable amounts of soil were printed to glass slides, Luria Bertani agar plates and broth filled 96-well plates at deposition rates exceeding 20 micro-particles per second, demonstrating the ability to isolate thousands of micro-particles of soil in minutes. Viability, culturability and significant morphological diversity were demonstrated post-printing., Results show that single step soil printing can be used to (a) generate pure microbial cultures (isolates), and (b) isolate consortia from a micro-ecological system that exists naturally in near-neighbor proximity, undisturbed from the environmental sample. [ABSTRACT FROM AUTHOR]

Abstract Engineering of a tissue construct that mimics a native tissue's form and function requires mimicry of the material, chemical, and morphological properties of the target tissue. Matching of these very properties makes fabrication of a composite structure challenging. The authors present a collection of techniques used to create multilayer three-dimensional soft-tissue constructs with high-resolution interlayer registration of individually printed two-dimensional patterns. These techniques include a bioreactor platform integrating NRL's Biological Laser Printing (BioLPTM) for quick and reproducible printing, culturing, and stacking of individual biopapers. The bioreactors were designed to mount and culture laser machined, stainless steel framed collagen biopapers. The biopapers in turn allowed for handling and high-resolution (<100 μm) registration of otherwise difficult to handle hydrogels. The authors demonstrate printing of endothelial cells onto the biopapers and culturing and tubulogenesis within the bioreactor. They also demonstrate high-resolution interlayer registration of biopapers individually printed with fluorescent beads. [ABSTRACT FROM AUTHOR]

A zero-power ballast control system that could be used to float and submerge a device solely using a gas source was built and tested. This system could be used to convey sensors, data loggers, and communication devices necessary for water quality monitoring and other applications by periodically maneuvering up and down a water column. Operational parameters for the system such as duration of the submerged and buoyant states can be varied according to its design. The gas source can be of any origin, e.g., compressed air, underwater gas vent, gas produced by microbes, etc. The zero-power ballast system was initially tested using a gas pump and further tested using gas produced by Clostridium acetobutylicum. Using microbial gas production as the only source of gas and no electrical power during operation, the system successfully floated and submerged periodically with a period of 30 min for at least 24 h. Together with microbial fuel cells, this system opens up possibilities for underwater monitoring systems that could function indefinitely. [ABSTRACT FROM AUTHOR]

A comparison has been made between laboratory test results from the ASTM E-2058 Fire Propagation Apparatus and the observed propagation behavior in an intermediate-scale fire test. The intermediate-scale fire test consists of two 2.4 m high parallel panels with a 60 kW fire source at the base. The intermediate-scale test determines whether a material could sustain upward fire spread under conditions associated with clean room hazards. Tests have been conducted with materials that, when used in the intermediate-scale test, provide examples of both propagating and non-propagating behavior. Eight polymeric materials are studied here four of which propagate and four of which do not propagate in the test. Ignition times have been measured at imposed radiant fluxes of 50 and 60 kW/m2 in laboratory tests with horizontal samples. Heat release rates have also been measured from horizontal samples at an imposed radiant flux of 50 kW/m2. In addition, the tests have been performed with vertical samples (measuring the propensity for propagation) with the bottom third of the sample exposed to a radiant flux of 50 kW/m2. Both the horizontal and vertical sample tests have been conducted in normal air and in air containing 40% oxygen. Of all the small-scale test series, the propagation tests with a vertically oriented sample in air containing 40% oxygen give the best correlation with the propagating behavior observed in the intermediate-scale parallel panel test series. [Copyright &y& Elsevier]

Gaining a greater understanding of the blood-brain barrier (BBB) is critical for improvement in drug delivery, understanding pathologies that compromise the BBB, and developing therapies to protect the BBB. In vitro human tissue models are valuable tools for studying these issues. The standard in vitro BBB models use commercially available cell culture inserts to generate bilayer co-cultures of astrocytes and endothelial cells (EC). Electrospinning can be used to produce customized cell culture substrates with optimized material composition and mechanical properties with advantages over off-the-shelf materials. Electrospun gelatin is an ideal cell culture substrate because it is a natural polymer that can aid cell attachment and be modified and degraded by cells. Here, we have developed a method to produce cell culture inserts with electrospun gelatin "biopaper" membranes. The electrospun fiber diameter and cross-linking method were optimized for the growth of primary human endothelial cell and primary human astrocyte bilayer co-cultures to model human BBB tissue. BBB co-cultures on biopaper were characterized via cell morphology, trans-endothelial electrical resistance (TEER), and permeability to FITC-labeled dextran and compared to BBB co-cultures on standard cell culture inserts. Over longer culture periods (up to 21 days), cultures on the optimized electrospun gelatin biopapers were found to have improved TEER, decreased permeability, and permitted a smaller separation between co-cultured cells when compared to standard PET inserts., (© 2016 Wiley Periodicals, Inc.)