Rapid prototyping of a single-use bioreactor: conceptional design studies to final product

It is widely acknowledged that single-use bioreactors can increase flexibility, reduce production costs, and improve productivity. Consequently, a multitude of single-use bioreactors, which greatly differ in geometry, size, agitation principle, sensors, and cultivation performance, have been developed over the last decade. In modern biomanufacturing processes, mechanically driven bioreactors, including stirred, wave-mixed and orbitally shaken systems, dominate due the extensive anecdotal and published information as well as readily available engineering data, and scale-up capabilities. These single-use bioreactors are primarily used for seed train and inoculum production but are also employed for vaccine and monoclonal antibody manufacturing. Driven by market adoption and evolution, Finesse Solutions has recently focused on expanding its SmartVessel™ bioreactor family. Based on fluid dynamic investigations that were conducted during early design studies, prototypes of a new single-use bioreactor were built by using rapid prototyping techniques. A variety of rapid prototyping techniques, such as stereolithography (SLA), laser sintering and 3D printing are now viable for this application and currently available for commercial use. Additionally, a large variety of different plastic materials are also available. Finding materials suitable for use in a cGMP environment is however still challenging; the polymers have to meet special requirements, including the absence of animal-component derived material, Bisphenol A (BPA), latex free, phthalate free – and must also be free of cytotoxic and carcinogenic components. Ideally the materials that meet the aforementioned criteria are also gamma irradiation compatible to levels in excess of 40 kGy. Based on a case study, this presentation provides some insights into the developmental process from conceptional bioreactor designs to a final product. Special focus is on the rapid prototyping that can enable faster time to market and reduced costs and the dichotomy between a rapid prototyped part and a molded part. Furthermore, aspects of the material selection with regards to cGMP compliance and stability for gamma irradiation are discussed

Recommendations for the engineering characterization of single-use bioreactors

Single-use bioreactors have been available for more than 15 years and are nowadays widely accepted for a broad range of applications. However, process engineering data for these bioreactors, including volumetric mass transfer coefficients, mixing times and power inputs, are still limited. Furthermore, these data are often generated using a number of different methods, making comparisons difficult. In addition, the large variety of bioreactor types and their mixing principles (stirred, wave-mixed, orbitally-shaken, etc.) increases the difficulty in comparing the engineering data. In order to facilitate the usage of single-use bioreactors, the DECHEMA Upstream Processing (USP) expert group on ‘Single-use technology in biopharmaceutical manufacturing’ has developed recommendations for the process engineering characterization of single-use bioreactors. The methods are based on procedures that were previously developed for multi-use bioreactors and were tested in universities as well as companies (both from the supplier and user sides) for their robustness. The validated recommendations now include measurements of volumetric mass transfer coefficient, mixing time and power input. These parameters are experimentally determined using the dynamic gassing-out method, the decolorization method or sensor method, and the torque method respectively. The poster gives an overview of the fundamentals and procedures of the methods applied, and current results from the interlaboratory tests. Recent foci include the measurement of carbon dioxide gas-liquid mass transfer and the determination of mechanical stress due to hydrodynamics

A simple rule for axon outgrowth and synaptic competition generates realistic connection lengths and filling fractions

Neural connectivity at the cellular and mesoscopic level appears very specific and is presumed to arise from highly specific developmental mechanisms. However, there are general shared features of connectivity in systems as different as the networks formed by individual neurons in Caenorhabditis elegans or in rat visual cortex and the mesoscopic circuitry of cortical areas in the mouse, macaque, and human brain. In all these systems, connection length distributions have very similar shapes, with an initial large peak and a long flat tail representing the admixture of long-distance connections to mostly short-distance connections. Furthermore, not all potentially possible synapses are formed, and only a fraction of axons (called filling fraction) establish synapses with spatially neighboring neurons. We explored what aspects of these connectivity patterns can be explained simply by random axonal outgrowth. We found that random axonal growth away from the soma can already reproduce the known distance distribution of connections. We also observed that experimentally observed filling fractions can be generated by competition for available space at the target neurons--a model markedly different from previous explanations. These findings may serve as a baseline model for the development of connectivity that can be further refined by more specific mechanisms.Comment: 31 pages (incl. supplementary information); Cerebral Cortex Advance Access published online on May 12, 200

Mass Production of Mesenchymal Stem Cells — Impact of Bioreactor Design and Flow Conditions on Proliferation and Differentiation

The book serves as a good starting point for anyone interested in the application of tissue engineering. It offers a colorful mix of topics, which explain the obstacles and possible solutions for TE applications. The first part covers the use of adult stem cells and their applications. The following chapters offer an insight into the development of a tailored biomaterial for organ replacement and highlight the importance of cell-biomaterial interaction. In summary, this book offers insights into a wide variety of cells, biomaterials, interfaces and applications of the next generation biotechnology, which is tissue engineering

Scaling‐up of an insect cell‐based virus production process in a novel single‐use bioreactor with flexible agitation

A novel single-use bioreactor was recently introduced to the market that is agitated by impellers suspended on flexible ropes rather than a rigid shaft. Computational fluid dynamics (CFD) models were created and validated by particle image velocimetry (PIV) to predict the bioreactor’s fluid flow and mixing. The data were then used to scale-up a Spodoptera frugiperda, subclone 9 (Sf9) insect cell-based production of recombinant adeno-associated virus (AAV) from a benchtop glass bioreactor to the single-use system with 30 L working volume. This viral vector is one of the most commonly used in gene therapies. The volumetric power input was kept constant while maintaining reasonable mixing times and shear stresses between the scales. Peak cell densities of up to 7.2·10^6 cells/mL and maximum virus titers of 1.7·10^11vg/mL were achieved. Similar cell growth and metabolite profiles further proved the successful process transfer between the two geometrically non-similar bioreactor systems. The pilot bioreactor yielded between 3.3 and 4.8·10^15 vg that, depending on the therapy, can be sufficient for the treatment of a single patient

Power input measurements in stirred bioreactors at laboratory scale

The power input in stirred bioreactors is an important scaling-up parameter and can be measured through the torque that acts on the impeller shaft during rotation. However, the experimental determination of the power input in small-scale vessels is still challenging due to relatively high friction losses inside typically used bushings, bearings and/or shaft seals and the accuracy of commercially available torque meters. Thus, only limited data for small-scale bioreactors, in particular single-use systems, is available in the literature, making comparisons among different single-use systems and their conventional counterparts difficult. This manuscript provides a protocol on how to measure power inputs in benchtop scale bioreactors over a wide range of turbulence conditions, which can be described by the dimensionless Reynolds number (Re). The aforementioned friction losses are effectively reduced by the use of an air bearing. The procedure on how to set up, conduct and evaluate a torque-based power input measurement, with special focus on cell culture typical agitation conditions with low to moderate turbulence (100 < Re < 2·104), is described in detail. The power input of several multi-use and single-use bioreactors is provided by the dimensionless power number (also called Newton number, P0), which is determined to be in the range of P0 ≈ 0.3 and P0 ≈ 4.5 for the maximum Reynolds numbers in the different bioreactors

BACCardI - a tool for the validation of genomic assemblies, assisting genome finishing and intergenome comparison

Bartels D, Kespohl S, Albaum S, et al. BACCardI - a tool for the validation of genomic assemblies, assisting genome finishing and intergenome comparison. Bioinformatics. 2005;21(7):853-859.Summary: We provide the graphical tool BACCardI for the construction of virtual clone maps from standard assembler output files or BLAST based sequence comparisons. This new tool has been applied to numerous genome projects to solve various problems including (a) validation of whole genome shotgun assemblies, (b) support for contig ordering in the finishing phase of a genome project, and (c) intergenome comparison between related strains when only one of the strains has been sequenced and a large insert library is available for the other. The BACCardI software can seamlessly interact with various sequence assembly packages. Motivation: Genomic assemblies generated from sequence information need to be validated by independent methods such as physical maps. The time-consuming task of building physical maps can be circumvented by virtual clone maps derived from read pair information of large insert libraries