Advanced therapies medicinal products (ATMPs) have introduced innovative cell-based products. However, the regulatory demands for characterization of ATMPs are currently unable to adequately address the safety of such products. As recent studies have emphasized the role of mitochondria in the osteogenic differentiation of human mesenchymal stem cells (hMSCs), we have studied in detail the viability and osteogenic differentiation potency of the hMSCs intended for use as ATMPs based on analyses of the mitochondrial inner membrane potential (DeltaPsi(m)). Flow cytometric measurement of 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1), propidium iodide fluorescence, and AnnexinV was employed to determine DeltaPsi(m), plasma membrane integrity, and organization of phosphatidylserine in plasma membrane, respectively, in cultured hMSCs. Apoptosis was induced by incubating cells at critical concentration (20 muM) of menadione. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used as an indicator for cell proliferation and alkaline phosphatase activity and calcium deposition as indicators of osteogenic differentiation. Based on JC-1 fluorescence, cell morphology, organization of phosphatidylserine, and plasma membrane integrity, we could sort cells into four categories that represented different cell quality. A strong correlation between JC-1 and osteogenic differentiation was demonstrated for the first time and thus this analytical tool is suitable not only to determine cell viability but also to predict osteogenic differentiation of hMSC.

Abstract-The future of educational technology has been envisioned to have increasing focus on simulations, game based learning, virtual learning environments and virtual worlds. The technologies aim to provide authentic learning and enable deeper, more complex and contextual understanding for students. To study the impact of virtual learning environments for natural sciences and engineering education, we have designed and implemented a virtual laboratory, LabLife3D, in Second Life. To date we have designed six virtual laboratory exercises in the biological sciences and chemistry and additionally created a system to gather behavioristic data during laboratory simulations for the purpose of learning analytics. This paper presents the design process of laboratory exercises and discusses the contentspecific learning goals and outcomes. Additionally, this paper discusses the use of heuristic usability review used to improve the virtual learning environment. Lastly, the results from student and teacher interviews are presented, together with results of the learning analytics study. The discussion also includes student identified affordances and barriers for learning. We conclude that authentic and deep learning is possible within virtual worlds. Furthermore, the results of this study are not only limited to virtual worlds, but could also apply to other areas of digital educational technology.

The effect of thermal modification and extracts of Scots pine sapwood and heartwood, and Norway spruce on the colonisation by the bacterium, Escherichia coli was studied. All wood samples caused more rapid decrease of bacterial numbers compared to glass, which was used as reference material. Pine sapwood caused somewhat faster decrease of bacterial count than the other wood types. On the other hand, both thermal modification and extraction increased the bacterial count on all the samples compared to untreated wood samples. Neither the amount of extractives nor the faster drying of the surface, to which the bacterial inoculum was added, could alone explain this result; rather it is likely that this is due to a combination of both factors.

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IntroductionOne of the most challenging safety issues in the manufacture of cell based medicinal products is the control of microbial risk as cell-based products cannot undergo terminal sterilization. Accordingly, sensitive and reliable methods for detection of microbial contamination are called for. As mitochondrial function has been shown to correlate with the viability and functionality of human mesenchymal stem cells (hMSCs) we have studied the use of a mitochondrial inner membrane potential sensitive dye for detecting changes in the function of mitochondria following infection by bacteria.MethodsThe effect of bacterial contamination on the viability of bone marrow-derived mesenchymal stem cells (BMMSCs) was studied. BMMSC lines were infected with three different bacterial species, namely two strains of Pseudomonas aeruginosa, three strains of Staphylococcus aureus, and three strains of Staphylococcus epidermidis. The changes in viability of the BMMSCs after bacterial infection were studied by staining with Trypan blue, by morphological analysis and by monitoring of the mitochondrial inner membrane potential.ResultsMicroscopy and viability assessment by Trypan blue staining showed that even the lowest bacterial inocula caused total dissipation of BMMSCs within 24 hours of infection, similar to the effects seen with bacterial loads which were several magnitudes higher. The first significant signs of damage induced by the pathogens became evident after 6 hours of infection. Early changes in mitochondrial inner membrane potential of BMMSCs were evident after 4 hours of infection even though no visible changes in viability of the BMMSCs could be seen.ConclusionsEven low levels of bacterial contamination can cause a significant change in the viability of BMMSCs. Moreover, monitoring the depolarization of the mitochondrial inner membrane potential may provide a rapid tool for early detection of cellular damage induced by microbial infection. Accordingly, mitochondrial analyses offer sensitive tools for quality control and monitoring of safety and efficacy of cellular therapy products.