Thermodynamic approach to explain cell adhesion to air–medium interfaces

Abstract

Cell damage has been observed in suspension cell cultures with air sparging, especially in the absence of any protective additives. This damage is associated with cells adhering to bubbles, and it has been shown that if this adhesion is prevented, cell damage is prevented. This article presents a thermodynamic approach for predicting cell adhesion at the air-medium interface. With this relationship it can be shown that cell-gas adhesion can be prevented by lowering the surface tension of the liquid growth medium through the addition of surface-active protective 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 empirical equations, are used to quantify the changes in free energy that predict the process of cell-gas adhesion. The thermodynamic model is nonspecific in nature and, consequently, results are equally valid for all types of cells. (c) 1995 John Wiley & Sons, Inc.

An investigation of small‐molecule surfactants to potentially replace pluronic F‐68 for reducing bubble‐associated cell damage

“…5). As previously reported (Chattopadhyay et al, 1995a;Dey and Emery, 1999) 1.0 g/L PF-68 can rapidly decrease the surface tension from 72 dyn/cm to around 55 dyn/cm within 0.1 s, followed by a slow decrease to the equilibrium surface tension reported by Chattopadhyay et al (1995b) to be 45 dyn/cm, as determined by the Wilhelmy plate method. In contrast, OM, NM, and CM4 rapidly (less than 0.1 s) lowered the surface tension with very little change after the initial drop, while 0.28 g/L DM took the longest, approximately 0.5 s, to achieve its equilibrium value.…”

“…Even though a number of protective mechanisms of PF-68 have been proposed (Chisti, 2000;Wu, 1995), the ability of PF-68 to inhibit cell-bubble attachment is considered the primary mechanism. Chattopadhyay et al (1995b) suggested that this inhibition of cell-interface adhesion is the result of PF-68 significantly decreasing the surface tension of the gas-liquid interface such that adhesion to the gas-liquid interface is thermodynamically unfavorable. The interaction of nonionic block copolymers (such as PF-68) with air-water interfaces is a significant subset area of research in the general area of surfactants, air-water interface interactions.…”

Effects of agitation on the microalgae Phaeodactylum tricornutum and Porphyridium cruentum

“…Cell damage could be suppressed by adding a small amount ( ‡0.02% by wt) of carboxy methyl cellulose to the culture medium [45]. Methyl cellulose additives have been associated with the reduced attachment of cells to bubbles [46][47][48][49].…”

The potential of hydrodynamic damage to animal cells of industrial relevance: current understanding

“…Given that the driving force of the bubble rupture process is a pressure difference, lowering the surface tension lowers the driving force which lowers the overall EDR associated with the bubble rupture. Lowering the surface tension of the gas-liquid interface also makes the attachment of cells to gas-medium interfaces thermodynamically unfavorable (Chattopadhyay et al 1995b). Michaels et al (1995) reported that PF-68 can significantly increase the induction time required before a cell-to-bubble attachment can occur to 5-20 s. This led Meier et al (1999) to create a mathematical model simulating the process of cells following streamline flows around a sphere to investigate the role of cell-to-bubble attachment in the total bubble-associated cell damage and reconcile some contradictory observations in the literature.…”