PORTEFEUILLE

Conventional multiplication of cell populations uses degrading enzymes to transfer cells to ever larger culture surfaces. This harmful procedure leads to loss of specific cell functions important for regenerative medicine. We have designed and built a novel device to reduce detrimental enzymatic treatments by expanding the culture surface itself. The large surface expansion achievable with our new material (~10-fold over ~2-fold of existing devices) together with automated control by a mechanical device (‘Cellerator’) can additionally reinforce desired phenotypes in mechanically responsive cells such as in fibroblasts, chondrocytes, myocytes, and arterial wall cells by altering the stretch mode (oscillating, gradual). Proof of principle is pursued by investigating the effect of substrate stretch on cell-surface interactions and mechanically-activated gene expression. This device offers new experimental possibilities in research areas including wound healing, metastases, stem cell differentiation and cell responses to mechanical stimulation.

By supporting this inventive and promising cell culture system the Gebert Rüf Stiftung is promoting the transfer of this technology from the laboratory into a commercial product with a multifaceted approach including (1) in-house use of the device for characterization of fibroblastic cell responses to substrate deformations, (2) collaborations with other laboratories for studies with other cell types, and (3) sales of the device to other laboratories.

Our novel highly extendable membranes (‘Elasdish’) for cell growth in the Cellerator exhibit adhesive properties that match those of standard culture vessels. The Elasdish is to sterilize, stored over months, shipped by regular mail and can be provided with different coatings for cell attachment. Elasdish culture has been established for skin fibroblasts and mesenchymal stem cells (MSC). Rapid culture expansion of autologous dermal fibroblasts is pivotal to obtain sufficiently high cell numbers for the treatment of large burn wounds. We obtained ~2-times more fibroblasts in 50% of the time needed for conventional culture. Formation of fibrotic fibroblasts was completely abolished, whereas standard culture induced this futile transition in ~40% of the cells.
Human MSC are relevant to repair bone, cartilage, and cardiovascular tissue. Bone-marrow derived MSC were cultured three passages on the Elasdish, each consisting 20 days expansion. After the 9 weeks, MSC still exhibited high proliferation, fully retained pluripotency and were inducible into fat, cartilage, bone, and muscle. Dynamic expansion culture produced ~10-times more MSC compared with conventional culture, which included nine harmful trypsin passages. Our method has two major advantages over conventional cell culture: 1) Longer culture and preservation of the cell phenotype because dynamic surface expansion avoids/reduces enzymatic passaging. 2) Higher and faster cell yield because the expansion protocol is freely adjustable to the respective cell growth rates and cell density can be kept constantly ideal for maximum proliferation.

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