An Origami Paper-Based Analytical Device Coupled with Fast-Responding Functional RNA Superstructures for Tetracycline Detection

Rapid and sensitive detection of tetracycline (TC) in the aquatic environment is important for the environmental ecosystem and human health. Herein, we presented on the first attempt to construct a fast-responding gating system by using horseradish peroxidase (HRP)-loaded functional RNA superstructures (HRP@3D RNA). Proteins were directly loaded into 3D RNA by the rolling circle transcription (RCT) reaction. We found that the specificity of aptamer-ligand interaction could serve as a triggered manner to release the loaded HRP from 3D RNA. The above general scheme showed a few minutes of rapid release kinetics. According to the controlled-release mechanism, we designed a disposable origami paper-based analytical device (doPAD) coupled with HRP@3D RNA for colorimetric detection of TC. This doPAD can realize target recognition and signal readout by taking advantage of the unique spatial control advantages of 3D origami, thus generating a signal of color change that is positively related to the concentration of TC. This doPAD achieved the quantitative analysis of TC with a limit of detection of 10nM within 41min. We envision that the platform will be widely used in the field of environmental monitoring and biosensing.