Enzyme-Free Amplified Detection of DNA by an Autonomous Ligation DNAzyme Machinery.

The Zn2+-dependent ligation DNAzyme is implemented as a biocatalyst for the amplified detection of a target DNA by the autonomous replication of a nucleic acid reporter unit that is generated by the catalyzed ligation process. The reporter units enhance the formation of active DNAzyme units, thus leading to the isothermal auto-catalytic formation of the reporter elements. The system was further developed and applied for the amplified detection of Tay-Sachs genetic disorder mutant, with a detection limit of 1.0 × 10-11 M. Besides providing a versatile paradigm for the amplified detection of DNA, the system reveals a new, enzyme-free, isothermal, autocatalytic mechanism that introduces means for effective programmed synthesis. [ABSTRACT FROM AUTHOR]