THERMODYNAMIC APPROACH TO EXPLAIN CELL-ADHESION TO AIR-MEDIUM INTERFACES

Cell damage has been observed in suspension cell cultures with air spa rging, especially in the absence of any protective additives. This dam age is associated with cells adhering to bubbles, and it has been show n that if this adhesion is prevented, cell damage is prevented. This a rticle presents a thermodynamic approach for predicting cell adhesion at the air-medium interface. With this relationship it can be shown th at cell-gas adhesion can be prevented by lowering the surface tension of the liquid growth medium through the addition of surface-active pro tective additives. The thermodynamic relationship describes the change in free energy as a function of the interfacial tensions between the (i) gas and liquid phases, (ii) gas and cell phases, and (iii) liquid and cell phases. Experimental data, along with theoretical and empiric al equations, are used to quantify the changes in free energy that pre dict the process of cell-gas adhesion. The thermodynamic model is nons pecific in nature and, consequently, results are equally valid for all types of cells. (C) 1995 John Wiley & Sons, Inc.