Large amounts of DNA-enriched biomaterials, such as salmon mills and shellfish gonads, are discarded as industrial waste around the world. We could convert the discarded DNA into a novel bio-matrix by the hybridization of DNA and metal ions, such as Al3+, Cr3+, Fe2+, Fe3+, CU+, CU2+, Zn2+, and Cd2+. These water-insoluble DNA-metal ion matrices could be created in various desirable forms, such as a gel, capsule, film, or fiber. DNA-Al3+ matrices were found to maintain a B-form DNA structure, which was the native double-stranded DNA structure in water. The DNA-Al3+ fiber showed flexibility with the molecular orientation in the direction of drawing. When a DNA-Cu2+ matrix was incubated in an aqueous hydroquinone or ascorbic acid solution, benzoquinone or dehydroascorbic acid was produced, respectively, by the oxidative effect Of CU2+ in the DNA-metal ion matrix. These results suggest that metal ions in the DNA-metal matrix maintained the oxidative function. The water-insoluble DNA-metal ion matrices may have a potential utility as a functional bio-material, such as an antibacterial, oxidative, bio-sensor, and ion conductive materials. (c) 2005 Elsevier Ltd. All rights reserved.