Chemical Sensing and Control in Cell & Tissue Bioreactors

To meet needs in cell and tissue engineering bioreactors are evolving to allow cells and tissues to be cultured under precisely defined physical and chemical conditions. Many cell-tissue types are now being cultured, and considered in this work are chondrocytes, vascular endothelial cells, and smooth muscle cells. The culture processes are dynamic and optimisation requires monitoring of key process variables. The chemical sensing in cell and tissue bioreactors described here has the long term aim of achieving automatic optimal control. Invasive and non-invasive electrochemical and optical systems are described for a wide range of target analytes (gases, ions, metabolites, hormones and proteins), but emphasis is on O₂, pH, CO₂ and glucose. The sensing is performed with: (a) interrogation via the bioreactor wall; (b) probes placed within the cell culture chamber; (c) analysis within a shunt/sampling chamber. Analysis of culture medium is used for measurement of glucose and for proteins that are markers of cell biosynthetic behaviour. Optical absorbance and scatter of cells and tissues are also investigated for both chemical and structural analysis