Patent ID: 8562953

Claim:
A dendritic polymer, comprising a structure as formula (I): S P-D X-Z-L) i ) 5 formula (I) wherein S is P is CH 2 CH 2 O l , and l is not less than 1, and P bonds with S by —CH 2 — bond, and P bonds with D by oxygen residual group; D is and i is 4, or is and i is 8, and D respectively bonds with X by the oxygen residual group, and D bonds with P by carbonyl residual group; X is a Z is a residual group of diethylene triaminepentaacetic acid, a residual group of ethylenedinitrilo tetraacetic acid, or and R 1 is and R 2 is H, methyl, ethyl, or propyl; and L is a metal cation.