Patent ID: 7198945

Claim:
A modified cell having a cell membrane to which is non-covalently bound a reaction product of an amphipathic compound and a physiologically active substance or a probe, wherein said amphipathic compound is represented by the following formula (1): wherein Z represents a residue of a compound having 2 to 10 hydroxyl groups; AO represents an oxyalkylene group having 2 to 4 carbon atoms; R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms; R 2 represents a residue of a compound having an aliphatic hydrocarbon group having 7 to 22 carbon atoms; X represents a group having at least one reactive functional group selected from succinimide group, maleimide group, amino group, carboxyl group, aldehyde group, glycidyl group, and thiol group; “a” represents 0 or 1; n1, n2, and n3 represent an average number of added moles of an oxyalkylene group having 2 to 4 carbon atoms, and each numerical number represented by n1, n2, n3, k1, k2, and k3 satisfies the following conditions: 0≦n1, n2≦500, 2≦n3≦500, and 2 ≦n 1 +n 2 +n 3≦500 0≦k1≦8, 1≦k2≦4, 1≦k3≦4, and 2 ≦k 1 +k 2 +k 3 ≦10; and wherein the physiologically active substance or probe reacts with the amphipathic compound at group X to produce the reaction product; and wherein the reaction product is non-covalently bound to the cell membrane through at least a portion of R 2 .