Recent Progress in DNA Biosensors: Target-Specific and Structure-Guided Signal Amplification

Deoxyribonucleic acid (DNA) is not only a fundamental biological molecule but also a versatile material for constructing sensitive and specific biosensing platforms. Its ability to undergo sequence-specific hybridization via Watson–Crick base pairing enables both precise target recognition and the programmable construction of nanoscale structures. The demand for ultrasensitive detection increases in fields such as disease diagnostics, therapeutics, and other areas, and the inherent characteristics of DNA have driven the development of a wide range of signal amplification strategies. Among these, polymerase chain reaction (PCR), rolling circle amplification (RCA), and loop-mediated isothermal amplification (LAMP) represent powerful target-based methods that enzymatically increase the concentration of nucleic acid targets, thereby boosting detection sensitivity. In parallel, structure-based strategies leverage the nanoscale spatial programmability of DNA to construct functional architectures with high precision. DNA can be used as a scaffold, such as DNA nanostructures, to organize sensing elements and facilitate signal transduction. It can also function as a probe, like aptamers, to recognize targets with high affinity. These versatilities enable the creation of highly sophisticated sensing platforms that integrate molecular recognition and signal amplification. Driven by DNA nano-assembly capability, both target-based and structure-based approaches are driving the advancement of highly sensitive, selective, and adaptable diagnostic technologies. This review highlights recent developments in DNA nano-assembly-driven amplification strategies.