Label-Free Fluorescent Determination of Simian Virus 40 Using Triplex DNA and G-Quadruplex/N-Methyl Mesoporphyrin IX

Abstract

Simian virus 40 (SV40) causes multiple diseases due to its low immunogenicity and strong infectivity. Here, the development of a label-free fluorescent sensor designed to detect double-stranded DNA (dsDNA) via a functionalized molecular beacon (MB) produced using triplex DNA and guanine (G)-quadruplexes is described. A SV40-specific dsDNA sequence was used as the target dsDNA (T-dsDNA). The MB was designed to comprise a G-quadruplex sequence, a complementary homopyrimidine sequence for T-dsDNA, and a partially complementary sequence for G-quadruplex sequence. Addition of T-dsDNA forces the MB to unfold, forming triplex DNA, and releasing the G-quadruplex sequence that binds to N-methyl mesoporphyrin IX (NMM), producing a signal. The G-quadruplex/NMM complex augments the signal at 610 nm and allows qualitative SV40 detection. Under optimal conditions, this strategy demonstrates a low limit of detection (0.4 nM). Compared to traditional biosensors, this sensor is enzyme-free, rapid, selective, sensitive, and was used to determine T-dsDNA in serum, suggesting that this strategy has applications in clinical analysis and for other viruses.

Keywords:

• Fluorescence
• G-quadruplex
• N-methyl mesoporphyrin IX
• Simian virus 40
• triplex DNA

Conflicts of interest

The authors declare that they do not have any conflicts of interest.

Availability of data and materials

The datasets from the current study are available from the corresponding author upon request.

Additional information

Funding

This work is supported by the Foundation and Applied Foundation Research Joint-Youth Fund project of Guangdong, China (2019A1515110648), the Project of Enhancing School with Innovation of Guangdong Ocean University (2020KZDZX1108), and Project of Enhancing School with Innovation of Guangdong Ocean University (230419054).