Design of multiplex logic gates: Combining regulation of DNA structure with logical calculation

In this paper, we proposed a facile and accurate way for controlling multiplex fluorescent logic gates through changing the exciting and the observing wavelengths. As proof-of-principle, a Pb2+-specific DNAzyme probe and a thymine (T)-rich DNA probe were introduced to a double-stranded (ds-) DNA. The addition style of the two ions served as the four inputs by changing the distance of the three fluorophores, 6-carboxyfluorescein (FAM), ALEXA 532 (ALEXA) and carboxytetramethylrhodamine (TAMRA), all of which were modified on the dsDNA probe. Compared with the previous methods, the present approach needed neither different inputs nor the change of sequence of the probe to achieve multiplex logic gates. Furthermore, the modularity of the strategy may allow it to be extended to other types of logic gates.