Biosensors Based on Isothermal DNA Amplification for Bacterial Detection in Food Safety and Environmental Monitoring

Abstract

The easy and rapid spread of bacterial contamination and the risk it poses to human health makes evident the need for analytical methods alternative to conventional time-consuming laboratory-based techniques for bacterial detection. To tackle this demand, biosensors based on isothermal DNA amplification methods have emerged, which avoid the need for thermal cycling, thus facilitating their integration into small and low-cost devices for in situ monitoring. This review focuses on the breakthroughs made on biosensors based on isothermal amplification methods for the detection of bacteria in the field of food safety and environmental monitoring. Optical and electrochemical biosensors based on loop mediated isothermal amplification (LAMP), rolling circle amplification (RCA), recombinase polymerase amplification (RPA), helicase dependent amplification (HDA), strand displacement amplification (SDA), and isothermal strand displacement polymerisation (ISDPR) are described, and an overview of their current advantages and limitations is provided. Although further efforts are required to harness the potential of these emerging analytical techniques, the coalescence of the different isothermal amplification techniques with the wide variety of biosensing detection strategies provides multiple possibilities for the efficient detection of bacteria far beyond the laboratory bench.

Keywords: bacteria; biosensor; environmental monitoring; food safety; helicase dependent amplification (HDA); isothermal DNA amplification; isothermal strand displacement polymerisation (ISDPR); loop mediated isothermal amplification (LAMP); recombinase polymerase amplification (RPA); rolling circle amplification (RCA); strand displacement amplification (SDA).

Figure 1

LAMP principle and example of a LAMP-based electrochemical biosensor using a capture probe, a biotin-labelled reporter probe, AuNP-labelled avidin and a carbon electrode.

Figure 2

RCA principle and example of an RCA-based SPR biosensor using an immobilised primer, a AuNP-labelled reporter probe and an SPR chip.

Figure 3

RPA Principle and example of an RPA-based SERS platform using biotin-labelled RPA products with different tails, AuNP-labelled reporter probes with different Raman reporters and streptavidin-coated MBs.

Figure 4

HDA principle and example of an HDA-based electrochemical biosensor using an immobilised primer, a FITC-labelled primer, an enzyme-labelled anti-FITC antibody and an ITO electrode.

Figure 5

SDA principle and example of an SDA-based electrochemical biosensor using a G-rich capture probe, a molecular switch, hemin and a gold electrode.

Figure 6

ISDPR principle and example of an ISDPR-based electrochemical biosensor using a methylene blue-labelled hairpin probe and a gold electrode.