Fluorescent aptasensors for parallel analysis of biomolecules based on interlocked DNA catenane nanomachines

Stimuli-responsive DNA catenane nanomachines have received considerable interest in the area of DNA nanotechnology. However, the sensing and bio-sensing applications of DNA catenane nanomachines are rarely explored. Herein, the biological small molecule and protein responsive DNA catenane nanomachines were designed by utilizing the specific aptamer/target interaction. In the presence of the target, the blocked catalytically inactive DNA catenane can be activated, while generating the metal ion-dependent DNAzyme as the signal output unit. The method allows the fluorescent detection of ATP and lysozyme with a detection limit of 20 nM and 200 pM, respectively. More importantly, through the use of different fluorophores as labels, the parallel analysis of ATP and lysozyme in the mixed solution was demonstrated based on two interlocked DNA catenanes. Compared with linear scaffold, the interlocked DNA rings showed enhanced stability against enzyme degradation and easily realized intramolecular reconfiguration. Due to its inherent advantages, the interlocked DNA catenane holds great promise in the field of DNA based sensors and nanodevices.