Programmed DNA walkers for biosensors

Abstract

Nowadays, due to excellent biological and polymeric characteristics, DNA has been widely noted as an emerging building block to construct diverse materials for biosensing, in vivo imaging, drug delivery, and disease therapy. Particularly, relying on programmability, predictability, and stability of DNA, DNA walkers have opened new and exciting opportunities in modern life sciences for target detection and biological analysis, which are constructed by self-assembly of DNA or combining DNA with other nanomaterials (e.g., quantum dots, gold nanoparticles, magnetic nanoparticles, polymers). Compared with conventional nanomaterials (lanthanide-doped upconversion nanoparticles, magnetic nanomaterials, carbon dots, silicon dots, and so on), DNA walkers showed convenient modification, lower biotoxicity, excellent biocompatibility and high biostability, improving the biological application. Meanwhile, with high-speed operating efficiency and sustainable operation, DNA walkers powered by strand displacement reaction or protein enzyme/DNAzyme reaction, have highly sensitive detection and signal amplification abilities, which are applied in biosensing, material assembly and synthesis, and early cancer diagnosis. Worthily, DNA walkers could be regarded as signal amplifiers, which enhanced the signal transduction and amplified biosensor sensing signals. Herein, we systematically and comprehensively summarized the operating principles of various DNA walkers, categorized rational design of the DNA walker, and outlined the application of DNA walker in biosensors. Furthermore, the challenges and future trends of DNA walkers were discussed.