Ratiometric Fluorescence Determination of Avian Influenza a Virus Subtype H1N1 DNA with Functionalized Quantum Dots and Gold Nanoparticles

Abstract

A new type of ratiometric fluorescence sensor based on DNA functionalized quantum dots (DNA-QDs) and gold nanoparticles (AuNPs) was constructed for sensitive fluorescence determination of the avian influenza A virus subtype H1N1 DNA. Using the nucleic acid strand displacement reaction, the carboxyfluorescein-DNA (FAM-DNA) replaced DNA-QDs on the surface of DNA-AuNPs, so that the fluorescence of QDs increased and the fluorescence of FAM decreased. In the presence of H1N1 DNA, the ends of the DNA on the AuNPs-DNA-QDs conjugates were blocked, preventing strand displacement. The fluorescence intensity ratio of FAM to QDs (F₅₂₀/F₆₂₄) was proportional to the concentration of H1N1 DNA. The linear range was from 2.5 to 20.0 nM with a limit of detection of 0.52 nM. Furthermore, this sensor showed good selectivity. This strategy is a simple, accurate, and sensitive tool to detect DNA biomarkers.

Keywords:

• Avian influenza A virus subtype H1N1 DNA
• DNA-QDs
• gold nanoparticles (AuNPs)
• quantum dots
• ratiometric fluorescence

Disclosure statement

There are no conflicts of interest to declare.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (21974101, 22174102), the Sino-German Rapid Response Funding for Covid-19 Related Research (C-0008), and the Large-Scale Instrument and Equipment Sharing Foundation of Wuhan University.