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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

SPR lab-on-a-chip.
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f7-sensors-12-10713: SPR lab-on-a-chip.

Mentions: SPR is largely based on total internal reflection. As shown in Figure 7, light hits the metal-liquid interface, and it exhibits total internal reflection due to the difference of refractive indices of metal and liquid. In SPR, there are two important modifications: (1) the incident light is polarized; and (2) the surface is a thin metal film coating, usually gold [40,41]. Polarization means that the light is oscillating only at a certain orientation, where normal light oscillates at various orientations. When light hits the gold surface, electrons and holes are created (just like photodiode). Because the incoming photons are oscillating only at one orientation, the generation of electrons/holes (electric charges) will also be oscillated at one direction. This charge oscillation can propagate parallel to the gold film, called evanescent wave. Also this propagation is short-lived, thus it does affect the reflected light. For a certain angle of incident light, the incident light can be matched to this evanescent wave (resonated). If this resonance happens, the light intensity of reflected light at that angle will be greatly reduced.


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

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

SPR lab-on-a-chip.
© Copyright Policy
Related In: Results  -  Collection

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

f7-sensors-12-10713: SPR lab-on-a-chip.
Mentions: SPR is largely based on total internal reflection. As shown in Figure 7, light hits the metal-liquid interface, and it exhibits total internal reflection due to the difference of refractive indices of metal and liquid. In SPR, there are two important modifications: (1) the incident light is polarized; and (2) the surface is a thin metal film coating, usually gold [40,41]. Polarization means that the light is oscillating only at a certain orientation, where normal light oscillates at various orientations. When light hits the gold surface, electrons and holes are created (just like photodiode). Because the incoming photons are oscillating only at one orientation, the generation of electrons/holes (electric charges) will also be oscillated at one direction. This charge oscillation can propagate parallel to the gold film, called evanescent wave. Also this propagation is short-lived, thus it does affect the reflected light. For a certain angle of incident light, the incident light can be matched to this evanescent wave (resonated). If this resonance happens, the light intensity of reflected light at that angle will be greatly reduced.

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