A self-powered rotating paper-based analytical device for sensing of thrombin

We firstly constructed a kind of self-powered rotating paper-based microfluidic chip and used it to detect thrombin. The integrated movable valve has the ability to control the fluid user-friendly on microfluidic paper-based analytical devices (µPADs), and this advantage let it convenient to implement the complex multistep operations. In addition, this technique is compatible and versatile to the self-powered µPADs at differing levels of complexity. To obtain the supercapacitor signal, the DNA sequence (DNA1) and a glucose oxidase (GOx) modified DNA sequence (GOx-DNA2) were linked with aptamer to form the sandwich structure. Then thrombin will combine with its specific aptamer by strong binding ability, and the GOx-DNA2 could be released and to catalyze the oxidation of glucose. Because of GOx-triggered reaction, the voltage can be generated to charge the paper supercapacitor and its signal could be monitored by digital multimeter. The assay shows good performance with wide linear range (3–1350 nM) and the limit of detection for the thrombin assay was down to 0.9 nM. The proposed rotating paper-based aptamer device can integrate the complex self-powered multistep operations, and show good potential to be applied for on-site assay in the field of diagnosis.