Patent ID: 8349621

Claim:
A ligand molecule-immobilized particle, comprising: a core particle, a surface of which has hydrophobicity and charge; and a ligand molecule-immobilized polymer immobilized to the surface of the core particle, wherein: the ligand molecule-immobilized polymer comprises a structure represented by the following general formula (1): where R 1 represents a ligand molecule-containing group, R 2 represents a hydrophobic group, R 3 represents a spacer site, R 4 represents a hydrophilic group, R 5 represents a group having charge, a to d specify a composition ratio and each represent an integer of 1 or more, and n and m specify chain lengths and represent integers satisfying relationships of 1 ≦n(a+b+c +d)≦10,000 and 1≦m≦350, a charge Q 1 of the group having charge in the ligand molecule-immobilized polymer, and a charge Q 2 on the surface of the core particle satisfy a relationship of Q 1 ×Q 2 <0 in a sample liquid, and the number of the ligand molecule-containing groups per particle is 200 or more to 900 or less.