4,6-Dibromo-isophthalic acid monohydrate.

In the crystal structure of the title hydrate, C(8)H(4)Br(2)O(4)·H(2)O, O-H⋯O hydrogen bonds link the mol-ecules into a two-dimensional network parallel to (10-2). The acid groups of the main mol-ecule and the water mol-ecule are all involved in the supra-molecular structure. The dihedral angles between the benzene ring and the acid groups are 37.

Colorimetric photonic hydrogel aptasensor for the screening of heavy metal ions.

We have developed a robust method for the visual detection of heavy metal ions (such as Hg(2+) and Pb(2+)) by using aptamer-functionalized colloidal photonic crystal hydrogel (CPCH) films. The CPCHs were derived from a colloidal crystal array of monodisperse silica nanoparticles, which were polymerized within the polyacrylamide hydrogel. The heavy metal ion-responsive aptamers were then cross-linked in the hydrogel network.