A chelation structure and method of forming and using the chelation structure. The chelation structure has a backbone that includes a linear sequence of monomeric backbone units, at least one polymer side chain, and at least one chelator side chain. The side chains are each covalently coupled to the backbone at one of the monomeric backbone units by a bond that is independently biodegradable or non-biodegradable. The chelation structure is synthesized by Radical Addition Fragmentation Transfer (RAFT), Atom Transfer Radical Polymerization (ATRP), or Free Radical Polymerization (FRP). The chelation structure, individually or in combination with a shuttle chelator, may be introduced into a mammal to bind an amount of a substance in a mammal, the substance being at least one of a metal and heme. The chelation structure has a log stability constant exceeding that of the shuttle chelator for binding the substance within cells of the mammal.