Short-term cell-attachment rates: a surface-sensitive test of cell-substrate compatibility

Mechanisms of cell deposition from a sessile liquid phase and adherence to various plastic substrates have been investigated by measurement of short-term (less than 120 min) cell-attachment rates. Sigmoidal attachment-rate curves were fit with a three-parameter variant of a logistic equation to quantify parameters related to initial rate and equilibrium-adherence. For substrates on which cell adhesion was low, initial rates were estimated from slopes of linear best-fit equations. Average variations in adherence parameters for three cell lines, MDCK (epithelioid), VERO, and AHL-1 (fibroblastic) to tissue-culture grade polystyrene dishes were less than 10% (standard-error-of-mean/mean X 100) over extended periods of more than two months, so that attachment measurements could be repetitively applied with the same cell stocks continuously subcultured in the laboratory. Developed techniques were applied to a variety of plastics and the results tabulated. Comparison of adherence parameters for ionomer and polyethylene films, both with and without adsorbed fetal-bovine-serum proteins, demonstrated that surface carboxyl groups were important in protein adsorption and cellular adherence. Attachment rates of MDCK to polystyrene were dependent on starting cell number whereas equilibrium adherence did not vary significantly over a wide range of inoculum concentrations. It was concluded from theoretical considerations that initial rates of MDCK attachment were sensitive to and dependent on electrostatic barriers to formation of close substrate contacts whereas equilibrium-adherence levels were controlled by short-range forces such as interfacial energies and formation of receptor-ligand complexes.