Speaker
Description
Introduction
Microfluidic cultivation platforms significantly improve the supply of tissue models in vitro. However, a key challenge is the sufficient distribution of oxygen and nutrients within a 3D construct. Here we demonstrate the use of collagen hollow filaments as a functional unit for the generation of a vascular structure in tissue engineering applications.
Methodology
The hollow filaments with a diameter < 1 mm were fabricated by direct extrusion of a collagen fibre suspension through a core-shell nozzle. The filaments were cross-linked, freeze-dried and mechanically characterised. The swelling behavior of the tubes and the permeability of the tube wall for nutrients and oxygen were analysed more in detail. Human endothelial cells (ECs) were seeded on the inner surface of the tubes and cultured under perfused conditions in a microfluidic circulation system. The shrinkage of the tube during cell cultivation was monitored also.
Results
The fibres are mechanically stable and permeable for oxygen and proteins. ECs growing on the inner surface showed typical features of a well-formed endothelium including VE-cadherin expression, cellular response to flow and secretion of extracellular matrix proteins. Cell growth was analysed over a period of 21 days. During this time, shrinkage of the cell-laden hollow tube was < 10%.
Conclusion
We were able to confirm that the collagen hollow filaments support the formation of a living vascular tissue over a long period. The fibres enable the delivery of nutrients and oxygen to a surrounding compartment. Therefore, the collagen hollow filaments could be used as a template for the fabrication of prevascularised tissue engineering constructs.
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