Improving efficiency of entropy-driven DNA amplification biosensing through producing two label-free signal strands in one cycle.

Entropy-driven circuits (EDC) provides one isothermal and non-enzymatic signal amplification strategy. But the efficiency of EDC signal amplification is not enough high because only one single strand can be produced in each cycle of the typical EDC system. In this work, we proposed one strategy to improve the amplification efficiency of EDC-based biosensing. In this strategy, two signal strands were produced in one cycle. The G-triplex (G3)-forming sequence was used as signal strand, and the G3/thioflavin T (G3/ThT) was used as label-free fluorescence reporter in this EDC-based biosensing. The detection limit of this method was estimated to be 3.4 pM for target DNA, which was about 10 times lower than that of the conventional EDC method. Furthermore, the response time was shortened from more than 1 h-0.5 h. In a word, one enzyme-free and label-free EDC strategy was proposed to construct an efficient nucleic acid biosensing platform.