| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 91 === The deposition of biological cells onto a rigid, planar charged surface is modeled theoretically. A cell is simulated by a rigid, spherical core covered by an ion-penetrable, charged membrane layer. The effects of the sizes of charged species, the surface potential of the plane, the thickness of membrane layer, the valances of ionic species, and the fixed charge density inside membrane layer, on the phenomenon under consideration are investigated. The results of numerical simulation reveal that the rate of cell deposition is faster, under following conditions: (1) lower surface potential of the charged surface, (2) thicker membrane, (3) higher counterion valance, (4) lower fixed charge density, (5) smaller counterions, (6) larger coions, (7) larger functional group, (8) lower pH value of solution. Neglecting the sizes of ionic species may lead to an appreciable deviation in both the electrical repulsive force between cell and surface and the rate of deposition. For example, if the total amount of functional groups in the membrane layer Ntot＝3.5x10-4 M, pH=7, the equilibrium constants for the dissociation of tri-protonic acidic functional groups are Ka1=5x10-3 M, Ka2=8x10-8 M, Ka3=6x10-10 M, the equilibrium constant for the dissociation of the basic functional groups is Kb=2.6x10-5 M, and the scaled electrical potential on the planar surface is ψ0=-0.30, then the positive deviation in the former is on the order of 20%, and that the negative deviation in the latter is about 75%.
|
|---|
