Metal ion induced-assembly of amylose in aqueous solution.

Cu(2+)/amylose assemblies of various sizes were prepared through the Cu(2+) ion induced-assembly of amylose. These assembly structures were characterized via transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), dynamic light scattering (DLS), (1)H NMR analysis, fluorescence spectroscopy (FL) and UV-vis absorption spectroscopy (UV-vis). The results from these characterizations revealed the existence of a complexation effect and/or a bridging effect between the hydroxyl groups of amylose and Cu(2+) ions, and that the formation of the hydrophobic domains promoted the formation of Cu(2+)/amylose assemblies. The use of other metal ions to induce the formation of spherical, flower- and wire-like amylose assemblies was investigated as well. A preliminary investigation on the ability of amylose to capture various metal ions was also performed, and the results of this work demonstrated that amylose could bind quantitatively metal ions that were at low concentrations. This work provided an alternative strategy for the recovery of precious metals from metal ion-containing aqueous solutions and the reduction of water pollution.