Advances in Electrochemiluminescence Biosensors Based on DNA Walkers

Mediated by Watson-Crick base-pairing principle, DNA can be used to construct multi-functional molecular machines, such as DNA walkers, tweezers, logic gates and motors. It is noteworthy that DNA walkers with the advantages of programmability and diverse structures within the micro-nano scale have attracted intense attention in the field of biosensing, bioimaging, drug delivery, and genetic diagnosis. DNA walkers are comprised of driving power, walking strands and the tracks. The driving power acts as an external stimulus and the tracks as a platform for the walking strands to move autonomously. Under the specific external stimulus as driving power, such as strand displacement strategies, enzymatic reactions and environmental condition stimulus, DNA walkers could realize the generation and amplification of signals. Electrochemiluminescence (ECL) biosensors, combining ECL technology and bio-identification strategies, exhibit the virtue of high sensitivity, wide linear response range and low background interference. Recently, the construction of DNA walker-based ECL biosensors can amplify the targets and signals via multiple identification and recycles, achieving ultrasensitive detection for diverse targets. Herein, this review systematically summarizes the construction of different types of DNA walkers and their applications in ECL biosensors. Ultimately, this review summarizes and discusses the prospects for DNA walkers.