Utilisation of a Bioreactor for Culture and Expansion of Epithelial Cells without the use of Trypsin or Enzymes

Objective: To develop a bioreactor for automated culture, maintenance, and collection of normal human keratinocytes using an enzyme-free propagation method. Methods: The culture of normal human epithelial keratinocytes was compared in two culture methods - a study team-developed automated bioreactor utilising an enzyme-free passage method, and a manual culture method. Cell size, glucose utilisation, and the proliferative capacity of the two cultures were evaluated. Results: An automated bioreactor, not using enzymes for passage, but instead using the novel Epithelial Pop Up Keratinocytes (ePUK)1 culture technique, resulted in an extended culture longevity and proliferative capacity in normal primary human keratinocytes. Daughter cells were collected up to three times per day utilising the bioreactor. The daughter cells produced by the bioreactor were smaller than daughter cells produced by the manual culture method. The proliferative capacity and health of the parent monolayer within both the bioreactor and the manual culture flask was dependent upon sufficient glucose availability. Due to the contact inhibition nature of epithelial keratinocytes, the bioreactor enabled the study of an adherent cell type soon after cytokinesis and before the cell has integrated as part of an adherent matrix. Conclusion: The study demonstrates that increasing the number of media changes per day as necessary, based on glucose utilisation, is necessary for prolonged longevity and functional productivity of ePUK cultures. Keywords: bioreactor, cytokinesis, epithelial, glucose, keratinocytes