Scaffolded biosensors with designed DNA nanostructures

In addition to its fundamental function as a genetic code carrier, the utilization of DNA in various material applications has been actively explored over the past several decades. DNA is intrinsically an excellent type of self-assembly nanomaterial owing to its predictable base-pairing, high chemical stability and the convenience it possesses for synthesis and modification. Because of these unparalleled properties, DNA is widely used as excellent recognition elements in biosensors and as unique building blocks in nanodevices. A critical challenge in surface-based DNA biosensors lies in the reduced accessibility of target molecules to the DNA probes arranged on heterogeneous surfaces, especially when compared to probe-target recognition in homogeneous solutions. To improve the recognition abilities of these heterogeneous surface-confined DNA probes, much effort has been devoted to controlling the surface chemistry, conformation and packing density of the probe molecules, as well as the size and geometry of the surface. In this review, we aim to summarize the recent progress on the improvement of the probe-target recognition properties by introducing DNA nanostructure scaffolds. A range of new strategies have proven to provide a significantly enhanced range in the spatial positioning and the accessibility of the probes to the surface over previously reported linear structures. We will also describe the applications of DNA nanostructure scaffold-based biosensors.