Kinetics of cell deposition under the action of an external field

Abstract

The kinetics of cellular depositon from a stagnant solution to a surface are studied, taking into account the combined effect of an interaction field between the cells and the surface and of an external field. Since the forces involved in the adhesion of cells to a surface are short ranged, the cells are conveyed to the vicinity of the surface only by the external field. The equations developed are general, in the sense that they are independent of any particular form of the potential energy function, provided that it presents an appreciable potential barrier between the cells and the deposition surface. The characteristic shape of the curve representing the decay of the fraction of cells in solution with time is shown to be affected by the value ofPt ^*, consisting of the probability per unit time,P, for the escape over the potential barrier, and the sedimentation time,t ^*. A simple inspection procedure of this curve can disclose the relative significance of the external field and of the potential barrier in the overall kinetics of deposition. In addition, such an inspection can reveal the existence of alterations in the cellular adhesiveness with increasing coverage of the deposition surface. By matching the equation obtained to experimental results, the cellular adhesiveness, in term ofP, and the sedimentation rate (in the case of very slow sedimentation) can be evaluated.