The present disclosure pertains to iodinated poly (
amino acid) compounds that comprise residues of alpha amino acids that comprise an alpha carboxyl group, an alpha amino group, and a primary-amine-containing
side chain comprising an amino group. The poly(
amino acid) compounds comprise
amide linkages formed from the alpha carboxyl groups and the amino groups of the primary-amine-containing side chains of the alpha amino acids forming the iodinated poly(
amino acid) compound, at least one of the residues of the alpha amino acids in the iodinated poly(amino acid) compound is covalently modified to include one or more
iodine atoms, and at least two of the
alpha amino acid residues in the iodinated poly(amino acid) compound are not covalently modified. The present disclosure also provides crosslinked radiopaque hydrogels formed from such iodinated poly(amino acid) compounds, methods of treatment using such iodinated poly(amino acid) compounds, and systems containing such iodinated poly(amino acid) compounds.