Label-Free Pathogen Detection by a Deoxyribozyme Cascade with Visual Signal Readout

Area of Science:

• Biotechnology
• Molecular Diagnostics
• Biosensors

Background:

• Accurate and rapid pathogen detection is crucial for public health.
• Existing methods for viral detection can be complex and require specialized equipment.
• Developing field-deployable diagnostic tools for emerging infectious diseases is a priority.

Purpose of the Study:

• To develop a novel, label-free, colorimetric nucleic acid-based test for pathogen detection.
• To demonstrate the test's efficacy in detecting Zika virus RNA.
• To assess the test's specificity against related flaviviruses.

Main Methods:

• Utilized nucleic acid sequence-based amplification (NASBA) for isothermal amplification of viral RNA.
• Employed a visual split deoxyribozyme (vsDz) probe system for amplicon interrogation.
• Incorporated a cascade of deoxyribozymes, including a phosphodiesterase and a peroxidase-like deoxyribozyme (PDz), for signal generation.
• Visualized results through a colorimetric reaction upon activation of the PDz by the vsDz-amplicon complex.

Main Results:

• Achieved detection of Zika virus RNA at concentrations of 10^6 copies/mL and higher.
• Generated a visible color signal within 2 hours of sample analysis.
• Demonstrated high specificity, successfully differentiating Zika virus from dengue and West Nile viruses.
• The assay is label-free and relies on visual detection.

Conclusions:

• The developed colorimetric nucleic acid test provides a rapid and sensitive method for Zika virus detection.
• The combination of isothermal amplification and visual deoxyribozyme-based detection offers a promising platform for instrument-free point-of-care diagnostics.
• This technology has the potential for cost-effective development of nucleic acid analysis tools for resource-limited settings.