Method of analyzing interaction between material and biological substance

The present invention provides a method of analyzing an interaction between a medical material and a biological substance. The method includes bringing particles having a material to be evaluated at least on the surface thereof into contact with a biological substance to thereby form composite particles, binding the biological substance directly or indirectly to a fluorescent label, and then measuring the fluorescence intensity of the bound matter with a flow cytometer to thereby analyze the interaction between the material and the biological substance. Based on the extent of this interaction, it can be assessed whether or not the material is usable as a medical material for artificial vessels and so on.