Adhesion of various species of suspension-cultured plant cells to inert substrates: initial interactions

Abstract

The extent of short-term adhesion of various suspension-cultured plant cell species to polymer substrates exhibiting a wide range of surface tensions was examined. Adhesion of cells with a relatively low surface tension, suspended in distilled water, to the polymers fluorinated ethylenepropylene (FEP), polystyrene (PS), polyethylene terephthalate (PET), and sulphonated polystyrene (SPS) increased with decreasing substrate surface tension following the sequence SPS < PET < PS < FEP. These results are in agreement with the predictions of a thermodynamic model of particle adhesion which considers the role of the substrate, suspending-liquid, and cellular surface tensions. In contrast, little adhesion of relatively high surface tension cells to any of the polymer substrates was observed. Electrostatic repulsive forces between these cells and the polymer surface prevent adhesion because the magnitude of the attractive van der Waals force is small. A correlation was observed between the general adhesiveness of the various cultured plant cell species, especially to the low surface tension substrates, and the cellular surface tension determined by measuring the water contact angle on smooth layers of the cells. The cellular surface tensions ranged from approximately 42 mJ/m 2 for Digitalis purpurea cells to approximately 70mJ/m 2 for Papaver somniferum cells. Adhesion of cells to the polymer substrates increased with decreasing cellular surface tension under otherwise identical conditions. These results are also consistent with thermodynamic model predictions.