Dynamic culturing systems can contribute to overcoming challenges of in-vitro fabrication and maintenance of
complex 3D tissues, however, the unique physiological conditions to which each tissue is subjected has been
hampering noteworthy developments for many engineered tissues. Here we report the development (design,
manufacturing and testing) of a micro bioreactor for the preparation, maintenance and/or conditioning of human multilayer tissues or multi-tissue structures, providing evidence for vascularized skin tissue-engineered analogues and ex-vivo human skin. The bioreactor comprises a sandwich modular structure of hard undeformable layers of medical grade polycarbonate intercalated with soft deformable layers of silicone. When compressed the soft layers expand laterally against the sample sealing the layers between fluid streams avoiding their intermixing. Furthermore, the bioreactor is modular so that by changing the thickness of the soft layers it can easily be adapted to accommodate samples with varied thicknesses. The bioreactor is capable of holding skin tissue samples of 8mm in diameter and of providing, without mixing, different
culture media corresponding to the three layers of the tissue, the outmost epidermis, the underneath dermis and the innermost adipose tissue. This feature allows nourishing each cell type/tissue layer with the specific cell culture medium, increasing the maintenance time of the native structure in the ex-vivo skin. Furthermore, the bioreactor permits establishing an air-liquid interface for the epidermis turnover in the skin explant, while still maintaining the separation of the culture media underneath. This dynamic culture system contributes to diminishing the time of preparation of complex tissues or multi-tissues and prolonging the viability and use of in vitro and ex-vivo tissues being, therefore, a valuable tool for drug discovery, personalized medicine and cancer development studies.
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