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Lab-on-a-chip pathogen sensors for food safety.

Yoon JY, Kim B - Sensors (Basel) (2012)

Bottom Line: Several different types of lab-on-a-chip biosensors, including immunoassay- and PCR-based, have been developed and tested for detecting foodborne pathogens.Their assay performance, including detection limit and assay time, are also summarized.Finally, the use of optical fibers or optical waveguide is discussed as a means to improve the portability and sensitivity of lab-on-a-chip pathogen sensors.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural and Biosystems Engineering, the University of Arizona, Tucson, AZ 85721, USA. jyyoon@email.arizona.edu

ABSTRACT
There have been a number of cases of foodborne illness among humans that are caused by pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, etc. The current practices to detect such pathogenic agents are cell culturing, immunoassays, or polymerase chain reactions (PCRs). These methods are essentially laboratory-based methods that are not at all real-time and thus unavailable for early-monitoring of such pathogens. They are also very difficult to implement in the field. Lab-on-a-chip biosensors, however, have a strong potential to be used in the field since they can be miniaturized and automated; they are also potentially fast and very sensitive. These lab-on-a-chip biosensors can detect pathogens in farms, packaging/processing facilities, delivery/distribution systems, and at the consumer level. There are still several issues to be resolved before applying these lab-on-a-chip sensors to field applications, including the pre-treatment of a sample, proper storage of reagents, full integration into a battery-powered system, and demonstration of very high sensitivity, which are addressed in this review article. Several different types of lab-on-a-chip biosensors, including immunoassay- and PCR-based, have been developed and tested for detecting foodborne pathogens. Their assay performance, including detection limit and assay time, are also summarized. Finally, the use of optical fibers or optical waveguide is discussed as a means to improve the portability and sensitivity of lab-on-a-chip pathogen sensors.

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Related in: MedlinePlus

Loop-mediated isothermal amplification (LAMP). Reprinted from [94] with permission © American Society for Microbiology.
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f14-sensors-12-10713: Loop-mediated isothermal amplification (LAMP). Reprinted from [94] with permission © American Society for Microbiology.

Mentions: One example of such isothermal nucleic acid amplficiation methods is Loop-mediated AMPlification (LAMP; Figure 14) [93,94]. LAMP is popular since it requires only a single enzyme (strand displacing polymerase) and no preliminary manipulations to build a molecular motif capable of continuous self-replication. The LAMP technique is based on the principle of a strand displacement reaction and the stem-loop structure that amplifies the target gene fragment under isothermal conditions. LAMP is different from PCR in that four or six primers perform the amplification of the target gene, the amplification uses a single temperature step at 60–65 °C for about 60 min, and the amplification products have many types of structures in large amounts. Thus, LAMP is easier to perform than PCR, as well as being more specific. Furthermore, gel electrophoresis is not needed, because the LAMP products can be detected indirectly by the turbidity that arises from a large amount of by-product, pyrophosphate ion, yielding an insoluble white precipitate of magnesium pyrophosphate in the reaction mixture. Since the increase in the turbidity of the reaction mixture according to the production of precipitate correlates with the amount of DNA synthesized, real-time monitoring of the LAMP reaction can be achieved by real-time measurement of turbidity.


Lab-on-a-chip pathogen sensors for food safety.

Yoon JY, Kim B - Sensors (Basel) (2012)

Loop-mediated isothermal amplification (LAMP). Reprinted from [94] with permission © American Society for Microbiology.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472853&req=5

f14-sensors-12-10713: Loop-mediated isothermal amplification (LAMP). Reprinted from [94] with permission © American Society for Microbiology.
Mentions: One example of such isothermal nucleic acid amplficiation methods is Loop-mediated AMPlification (LAMP; Figure 14) [93,94]. LAMP is popular since it requires only a single enzyme (strand displacing polymerase) and no preliminary manipulations to build a molecular motif capable of continuous self-replication. The LAMP technique is based on the principle of a strand displacement reaction and the stem-loop structure that amplifies the target gene fragment under isothermal conditions. LAMP is different from PCR in that four or six primers perform the amplification of the target gene, the amplification uses a single temperature step at 60–65 °C for about 60 min, and the amplification products have many types of structures in large amounts. Thus, LAMP is easier to perform than PCR, as well as being more specific. Furthermore, gel electrophoresis is not needed, because the LAMP products can be detected indirectly by the turbidity that arises from a large amount of by-product, pyrophosphate ion, yielding an insoluble white precipitate of magnesium pyrophosphate in the reaction mixture. Since the increase in the turbidity of the reaction mixture according to the production of precipitate correlates with the amount of DNA synthesized, real-time monitoring of the LAMP reaction can be achieved by real-time measurement of turbidity.

Bottom Line: Several different types of lab-on-a-chip biosensors, including immunoassay- and PCR-based, have been developed and tested for detecting foodborne pathogens.Their assay performance, including detection limit and assay time, are also summarized.Finally, the use of optical fibers or optical waveguide is discussed as a means to improve the portability and sensitivity of lab-on-a-chip pathogen sensors.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural and Biosystems Engineering, the University of Arizona, Tucson, AZ 85721, USA. jyyoon@email.arizona.edu

ABSTRACT
There have been a number of cases of foodborne illness among humans that are caused by pathogens such as Escherichia coli O157:H7, Salmonella typhimurium, etc. The current practices to detect such pathogenic agents are cell culturing, immunoassays, or polymerase chain reactions (PCRs). These methods are essentially laboratory-based methods that are not at all real-time and thus unavailable for early-monitoring of such pathogens. They are also very difficult to implement in the field. Lab-on-a-chip biosensors, however, have a strong potential to be used in the field since they can be miniaturized and automated; they are also potentially fast and very sensitive. These lab-on-a-chip biosensors can detect pathogens in farms, packaging/processing facilities, delivery/distribution systems, and at the consumer level. There are still several issues to be resolved before applying these lab-on-a-chip sensors to field applications, including the pre-treatment of a sample, proper storage of reagents, full integration into a battery-powered system, and demonstration of very high sensitivity, which are addressed in this review article. Several different types of lab-on-a-chip biosensors, including immunoassay- and PCR-based, have been developed and tested for detecting foodborne pathogens. Their assay performance, including detection limit and assay time, are also summarized. Finally, the use of optical fibers or optical waveguide is discussed as a means to improve the portability and sensitivity of lab-on-a-chip pathogen sensors.

Show MeSH
Related in: MedlinePlus