Issue 24, 2017

Terahertz spectroscopy for the isothermal detection of bacterial DNA by magnetic bead-based rolling circle amplification

Abstract

The demand for rapid and sensitive bacterial detection is continuously increasing due to the significant requirements of various applications. In this study, a terahertz (THz) biosensor based on rolling circle amplification (RCA) was developed for the isothermal detection of bacterial DNA. The synthetic bacterium-specific sequence of 16S rDNA hybridized with a padlock probe (PLP) that contains a sequence fully complementary to the target sequence at the 5′ and 3′ ends. The linear PLP was circularized by ligation to form a circular PLP upon recognition of the target sequence; then the capture probe (CP) immobilized on magnetic beads (MBs) acted as a primer to initialize RCA. As DNA molecules are much less absorptive than water molecules in the THz range, the RCA products on the surface of the MBs cause a significant decrease in THz absorption, which can be sensitively probed by THz spectroscopy. Our results showed that 0.12 fmol of synthetic bacterial DNA and 0.05 ng μL−1 of genomic DNA could be effectively detected using this assay. In addition, the specificity of this strategy was demonstrated by its low signal response to interfering bacteria. The proposed strategy not only represents a new method for the isothermal detection of the target bacterial DNA but also provides a general methodology for sensitive and specific DNA biosensing using THz spectroscopy.

Graphical abstract: Terahertz spectroscopy for the isothermal detection of bacterial DNA by magnetic bead-based rolling circle amplification

Supplementary files

Article information

Article type
Paper
Submitted
30 Aug 2017
Accepted
19 Oct 2017
First published
20 Oct 2017

Analyst, 2017,142, 4661-4669

Terahertz spectroscopy for the isothermal detection of bacterial DNA by magnetic bead-based rolling circle amplification

X. Yang, K. Yang, X. Zhao, Z. Lin, Z. Liu, S. Luo, Y. Zhang, Y. Wang and W. Fu, Analyst, 2017, 142, 4661 DOI: 10.1039/C7AN01438D

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