Assembled molecular beacon-based self-propelled DNA machine for enzyme-free and distinctly amplified nucleic acid detection

Sensitive nucleic acid detection by simple, rapid, cost-effective and enzyme-free amplified strategy is continually pursued for its extensive applications in bioanalysis and clinical disease diagnosis. Herein, an assembled molecular beacon-based self-propelled DNA machine was proposed for enzyme-free and distinctly amplified nucleic acid detection. The sensing system was consisted of three different DNA subunits and an assembled molecular beacon (aMB). Owing to the facile and programmable signal output of aMB, current strategy demonstrated twolevel signal amplification capability for target detection: 1) target-triggered assembly unit could circularly dissociate aMB for the first-level signal amplification; 2) the liberated DNA sequence from the aMB could work as target analogy, contributing to the cascade and self-propelled signal amplification toward target DNA. The whole sensing system was well characterized by rational design of control experiments. The advantages of such sensing system also include assay simplicity (one-step mixing process) and no participation of protein enzyme. An attractive detection performance toward nucleic acid target (low detection limit of 10 fM, linear range of 0.1 pM0.1 nM) could be achieved. It was also suitable for nucleic acid analysis in the relatively complicated biological matrix such as serum. Thus, current assembled molecular beacon-based DNA machine might be explored to develop various sensing systems for the potential applications in bioanalysis and clinical disease diagnosis.

Automated summary

The study introduces an assembled molecular beacon-based self-propelled DNA machine for enzyme-free and distinctly amplified nucleic acid detection. The sensing system shows two-level signal amplification capability, enabling highly sensitive detection of nucleic acid targets and suitability for analysis in complex biological matrices.