DNA microsponge-templated growth of metal nanoparticles for signal-enhanced colorimetric detection

Metallic nanoparticle-based probes have been widely developed for cell detection. With the development of nucleic acid technology, the combination of DNA with metallic materials has drawn increased attention. However, the process of conjugating metal nanoparticles to a targeting moiety for sensing applications is inconvenient. We introduce the fabrication of DNA-iron oxide hybrid structures produced by co-precipitation. Using the rolling circle amplification method, highly porous and anionic DNA microsponges are produced. These exhibit numerous active sites for electrostatic interactions with cationic metal salts and produce DNA-templated hybrid structures. Iron oxide nanoparticles were homogeneously synthesized on an individual DNA scaffold without agglomeration. DNA microsponges with concentrated iron oxide nanoparticles exhibit the biological functions of DNA materials, such as cell targeting by aptamers, and can be detected by colorimetric assay via Prussian blue staining.