Platelet aggregation induced by latex particles. I. Effects of size, surface potential and hydrophobicity of particles.

Latex particles induced platelet aggregation associated with the release of ATP from the platelets. The smaller the diameter of particles having the same surface structure, the greater numbers or greater total surface area of particles were required for both reactions. The higher hydrophobic and higher negatively charged particles, having a diameter of about 0.3 micron, induced platelet aggregation most easily. Hydrophilic particles without high negative surface potential activated platelets only a little. Particle-induced platelet aggregation is not only caused by colloidal electronic force and hydrophobic interaction between platelets and latex particles but also by factors concerning cell activation.