Modular DNA Circuits for Point-of-Care Colorimetric Assay of Infectious Pathogens.

Accurate, specific, and inexpensive detection of multiple infectious pathogens simultaneously is a significant goal for human health and safety. Herein we present a rationally designed modular DNA circuit for point-of-care (POC) detection of a variety of infectious pathogens based on nucleic acid isothermal amplification technology and DNAzyme-mediated colorimetric readout. A modular DNA circuit was constructed with a fixed module and a flexible module and was rationally designed according to genetic targets. On this basis, the platform could detect multiple genetic targets corresponding to infectious pathogens simultaneously. Signal amplification properties of the DNA circuit and the peroxidase-like DNAzyme enable the detection limits to reach the picomolar level. By urea treatment and magnetic separation, the fixed module can be reused at least five times, which makes this assay more economical and environmentally friendly. The detection of genetic infectious pathogens should be accomplished in 2 h with naked-eye observation and may provide an efficient tool for POC analysis of multiple infectious pathogens, especially in resource-poor areas.