Interaction of poly(L-lysine-alt-terephthalic acid) microcapsules with fibrinogen

Interaction of poly(L-lysine-alt-terephthalic acid) microcapsules with fibrinogen was investigated by measuring the degree of microcapsule disintegration, fibrinogen adsorption to microcapsules, and the zeta potential of microcapsules as a function of fibrinogen concentration in phosphate buffer solutions of pH 7.4 at different ionic strengths. A minimum concentration was found to exist for fibrinogen to cause disintegration of the microcapsules at any ionic strength, and at this fibrinogen concentration the fibrinogen adsorption levelled off and the zeta potential exhibited an abrupt change. Increases in the ionic strength of the medium and the surface hydrophobicity of microcapsules produced an increase in the degree of microcapsule disintegration by fibrinogen. These findings were interpreted as showing that the interaction of the microcapsules with the protein is not of an ionic nature but of a hydrophobic nature.