Automated foam control in single-use bioreactors using the single use foam probe

Headspace foam in bioreactors can cause significant issues to a biological process among which are unfavorable metabolic conditions for cells, increased shear from bursting bubbles, cell death/entrainment, mass transfer interference and potential fouling of exhaust filters which can allow a point of entry for contamination or lead to pressure build-up and possible failure of the bioprocess container. This study investigates the efficacy of using a single use foam probe coupled with an automated response of an antifoam addition with an integrated DeltaV controller. Two 50L S.U.B.s run in parallel clearly illustrate differences; the first employing foam control using the foam probe and the second 50L S.U.B. where foam is manually controlled via a dosing interval and manual additions when determined by the operator. Please click Additional Files below to see the full abstract

Continuous Process Performance Enhancements for 50-500 L S.U.B.s

Improvements in single-use systems have allowed implementation of high-density cultures in emerging bioprocess workflows while progressive advances in media optimization and improved clone genetic selection have underscored the perceived performance limitations of single-use bioreactors (S.U.B.s). This study presents how strategic enhancements to the sparge and agitation systems of Thermo Scientific™ HyPerforma™ S.U.B.s have revealed the potential for a three- to four-fold improvement of mixing and mass transfer performance compared to legacy SUB designs. This study investigates the following: Bioreactor characterization, TruBio™ DeltaV™ controller optimization, online process analytics, and scalability analysis of the S.U.B. when targeting perfusion applications from 50 L pilot scale to 500 L production scale working volumes. High-density culture results (\u3e260E06 cells/mL) while maintaining proper operating parameters. New data reveal how a 50 L S.U.B. – equipped with a specialized precision drilled-hole sparger (DHS), single-use foam probe, and oversized impeller – is able to improve overall S.U.B. operating efficiency. Results also include specific suggestions on how to maintain a nearly ideal dissolved carbon dioxide environment, reduce headspace foam generation, and produce lower overall shear levels, thus yielding excellent cell viability. The work also demonstrates best practices and the desirable process benefits that can be achieved through reduced technical risk, lower labor, and simplified technical transfer of a completely disposable processing assembly. Further evidence is presented on the advantages of continuous processing when used in high-density seed train intensification or as a compact production-scale bioreactor system operating at reasonable media exchange rates of one to two vessel volumes per day (VVD). Please click Additional Files below to see the full abstract

Optimization of the single use bioreactor for growth and bead-to-bead transfer of Vero cells cultured on microcarriers

Scale up and vaccine production processes of adherent cells, such as Vero cells face many challenges. The fundamental steps of equipment selection and chosen operating parameters have a significant impact upon the detachment and reattachment of cells through the scale up process. Microcarriers greatly increase the surface area for adherent cells and offer flexibility for expansion to bioreactors, but scale-up methods require optimization of the mixing within the vessel and also optimization of how the cells are transferred from bead to bead at each step in the seed train. In this study we take a process previously shown to a work in spinner flasks (\u3c1L)1 and demonstrate how the 50L Thermo Scientific™ HyPerforma™ Single-Use Bioreactors (S.U.B.) can be optimized for growing and scaling adherent cells on microcarriers, methods for bead-to-bead transfer of the cells at each scaling step, and final cell isolation using the Harvestainer single use bead capture bag. References Hachmann A, Campbell A, Gorfien S. Scale-up Optimization of Vero Cells Cultured on Microcarriers in Serum-Free Medium for Vaccine Production. Poster presented at: Vaccine Technology VI; 2016 June 12-17; Albufeira, Portugal

Islet Encapsulation: Strategies to Enhance Islet Cell Functions

Diabetes is one of the most prevalent, costly, and debilitating diseases in the world. Although traditional insulin therapy has alleviated the short-term effects, long-term complications are ubiquitous and harmful. For these reasons, alternative treatment options are being developed. This review investigates one appealing area: cell replacement using encapsulated islets. Encapsulation materials, encapsulation methods, and cell sources are presented and discussed. In addition, the major factors that currently limit cell viability and functionality are reviewed, and strategies to overcome these limitations are examined. This review is designed to introduce the reader to cell replacement therapy and cell and tissue encapsulation, especially as it applies to diabetes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63384/1/ten.2006.0183.pd

Surface layering of liquids: The role of surface tension

Recent measurements show that the free surfaces of liquid metals and alloys are always layered, regardless of composition and surface tension; a result supported by three decades of simulations and theory. Recent theoretical work claims, however, that at low enough temperatures the free surfaces of all liquids should become layered, unless preempted by bulk freezing. Using x-ray reflectivity and diffuse scattering measurements we show that there is no observable surface-induced layering in water at T=298 K, thus highlighting a fundamental difference between dielectric and metallic liquids. The implications of this result for the question in the title are discussed.Comment: 5 pages, 4 figures, to appear in Phys. Rev. B. 69 (2004

Scoping studies to establish the capability and utility of a real-time bioaerosol sensor to characterise emissions from environmental sources

A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm−3 and 0.48 cm−3, respectively) and the composting site (2.32 cm−3 and 0.46 cm−3, respectively) and the lowest at the dairy farm (1.03 cm−3 and 0.24 cm−3, respectively) and the sewage treatment works (1.03 cm−3 and 0.25 cm−3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores

Shall we pay all? An experimental test of Random Incentivized Systems

This study seeks to investigate the impact of payment procedures on behavior in a standard Dictator game. Although the Between-subjects Random Incentivized System (BRIS) is increasingly utilized in experimental economics, its use could be contested from a purely theoretical point of view. In the BRIS, all subjects play the Dictator game, but only a percentage of subjects (e.g., 1 out of 10) are paid. The aim of this article is to test whether the results obtained using this system are consistent with those obtained using a conventional full payment system in which every subject receives payment. An additional, hypothetical treatment is also run. Results show a very similar pattern between the BRIS and the full payment treatment, whereas the hypothetical payment mechanism leads to far fewer egoistic players and far more egalitarians. These findings lend support to the use of BRIS as a valid experimental methodology

Open science in archaeology

No abstract available