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Our research projects include the development of isolation
and cultivation methods for the patient’s own basal skin
cells (adult stem cells and transient amplifying (TA) cells), and the
simultaneous isolation of connective tissue cells (skin
fibroblasts) from the same donor.
In addition to studies on the improvement
of culture media, we are working on special hollow
fiber membrane bioreactors for regenerative cell therapies
to support "tissue engineering
in the wound" by an active wound dressing.
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After opening the bioreactor, a single cell system
can be removed and transferred onto the wound
where capillary membranes provide oxygenation
and nutrition during the initial growth phase.
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Transfer of single cells with permeable hollow fiber membranes onto the wound.
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Although the skin is normally capable of regeneration
following injuries to the upper skin layer (epidermal cells,
keratinocytes), larger and deeper wounds that destroy the
regenerative layer (basal keratinocytes) and the dermal
structures do not heal by themselves.
Such injuries require the use of so-called split skin graft
techniques, whereby a skin graft is taken from uninjured
parts of the body and is subsequently split into many smaller
patches for transplantation. Large surfaces, however,
cannot be treated with traditional methods of skin
transplantation because there is not enough undamaged
skin available. Particularly in the case of burn injuries, the
loss of cells capable of division (stem cells, TA cells and other basal cells) cannot be
compensated.
In 1979 Green and Kehinde described the first clinical
results on the transplantation of keratinocytes proliferated
in culture flasks. Keratinocytes were isolated from small
skin biopsies taken from the patient, grown in culture dishes
and then transplanted onto the wound. The culture of
keratinocytes is now an established technique. The service
of producing these autologous skin transplants is offered
by a number of biotechnology companies.
However, cell nutrition during the initial growth phase has
proven deficient in current techniques resulting e.g. in shifts
in electrolyte and pH values and the accumulation of toxins
in the wound. This non-physiological wound biomatrix
inhibits optimal growth and proliferation of the transplanted
cells.
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Prototype bioreactor housing
with removable capillary membrane system,
which is |