Ultrasensitive Detection of Metal Ions with DNA Nanostructure

: In spite of its greatly scientific and technological importance, developing rapid, low cost and sensitive microarray sensors for onsite monitoring heavy metal contamination remains challenging. Here we develop a DNA nanostructured microarray (DNM) with a tubular three-dimensional sensing surface and an ordered nanotopography for rapid and sensitive multiplex detection of heavy metal ions. In our design, DNA tetrahedral-structured probes (TSPs) are used to engineer the sensing interface with spatially resolved and density-tunable sensing spots, improving the micro-confined molecular recognition. Meanwhile, a bubble-mediated shuttle reaction inside the DNM-functionalized microchannel improves the target-capturing efficiency. Thus, the sensitive and selective detection of multiple heavy metal ions (i.e., Hg2+, Ag+, and Pb2+) with this novel DNM biosensor can be achieved within 5 min. Moreover, the detection limit is down to 10, 10, and 20 nM for Hg2+, Ag+, and Pb2+, respectively. Therefore, the DNM biosensor capable of simultaneously detecting multiple heavy metal ions with sensitivity and selectivity shows great potential to be point-of-test devices.