Distance-based paper sensor for DNase I detection based on aptamer-mediated enzyme cascade reaction

Abstract

DNase I is proven to be an early predictive molecule for a variety of diseases, which is important for early diagnosis and clinical detection of diseases. Herein, we demonstrate a distance-based paper sensor to detect DNase I via an enzymatic cascade reaction mediated by the thrombin aptamer. In the presence of DNase I, the thrombin is able to clot the plasma normally because the aptamer chain is hydrolyzed by DNase I and cannot bind thrombin properly to inhibit thrombin activity. The concentration of DNase I is negatively correlated with the volume of mobile phase in sample solution, and it can be quantified by measuring the flow distance of water on the pH indicator strip. The distance-based paper sensor has good specificity, and the detection limit is 2 × 10−2 U/mL. In addition, it can be used for DNase I analysis in human serum samples to show its efficacy in the early diagnosis of diseases associated with DNase I activity. Overall, we developed a simple, fast and low-cost DNase I detection method, which has great commercial potential.