DNA Nanobridge with Cascade Operation Logic on a Transistor for Comprehensive Evaluation of Respiratory Infection.

Acute respiratory infections may cause a cytokine storm that poses a great threat to life. Thus, on-site pathogen screening and infection severity assessment are highly desired for immediate medical intervention. Here, we report the comprehensive monitoring of respiratory infection by a graphene field-effect transistor (g-FET) modified with a DNA nanobridge that consists of two DNA tetrahedrons linked by a bridge strand. The recognition of target viral nucleic acid triggers bridge dissociation, releasing the probe to detect the inflammatory cytokine IL-6. Such a cascade logical operation enables simultaneous detection of respiratory pathogens and evaluation of the associated inflammatory response. The device detects viral nucleic acid as low as 3.9 × 10-16 M, while the presence of IL-6 at a clinically relevant level of 2.4 × 10-12 M enhances the response by 3.7-fold. Thus, testing of clinical COVID-19 oropharyngeal swabs achieves ∼97.2% overall agreement with PCR results, demonstrating immense potential in practical applications.