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System Integration - A Major Step toward Lab on a Chip.

Sin ML, Gao J, Liao JC, Wong PK - J Biol Eng (2011)

Bottom Line: It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics.In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications.Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ 85721, USA. pak@email.arizona.edu.

ABSTRACT
Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.

No MeSH data available.


Test strip platform. (A) Schematic design of a test strip platform [51]. The sample fluid is drawn from the sample pad into the conjugate pad and membrane through the capillary action. (B) Immunoassays on the test strip. At the conjugate pad, nanoparticle-labeled-antibody rehydrate and bind with the specific antigen in the sample. Two different capturing antibodies are sprayed at the test line T and the control line C. At the test line, the antibody bind with the nanoparticle-labeled-antibody/antigen complex (positive assay) while the control line attach with the nanoparticle-labeled-antibody complex (proof of successful assay). (C) Image of commercially available pregnancy test strips [219].
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Figure 1: Test strip platform. (A) Schematic design of a test strip platform [51]. The sample fluid is drawn from the sample pad into the conjugate pad and membrane through the capillary action. (B) Immunoassays on the test strip. At the conjugate pad, nanoparticle-labeled-antibody rehydrate and bind with the specific antigen in the sample. Two different capturing antibodies are sprayed at the test line T and the control line C. At the test line, the antibody bind with the nanoparticle-labeled-antibody/antigen complex (positive assay) while the control line attach with the nanoparticle-labeled-antibody complex (proof of successful assay). (C) Image of commercially available pregnancy test strips [219].

Mentions: The test stripe platform consists of fleeces, which can draw liquid through stripes using the capillary effect (Figure 1a). The sample liquid, such as urine and blood, reacts with the reactants pre-immobilized on the stripe. The capillary filling action can be influenced by the permeability, the roughness, the dimension, the surface properties, and the total number of capillaries inside the stripe [51]. The fleece can also serve as a sample filter, which is essential for processing many physiological and environmental samples. For example, in blood analysis, blood cells can be blocked from entering into the reaction chamber. This eliminates the need for centrifugal separation [52]. Adequate and precise incubation of the sample with the reactant is also required for reactions to occur. Incubation time can be controlled by slowing down the capillary flow with local modifications of the channel geometry and property [51]. It should be noted that metering of sample liquid in the test stripe is important for quantitative assay. To ensure the well defined amount of liquid has passed the detection zone, the start reservoir should be filled with enough sample liquid. The liquid flow stops automatically in the end reservoir when the whole piece of fleece is fully wetted with liquid. The detectable signal of the test stripe assay can be measured quantitatively by engineering interfaces or qualitatively by manual observation in the detection zone. For optical detection, the diagnostic section can be illuminated by a laser diode and the resulting fluorescence emission of the fluorescently labeled analytes can be detected by a photodiode [53,54]. For qualitative readout, the analytes can be bound to small gold nano particles or colored latex particles. Accumulation of the analytes at the detection zone can produce a readable signal [51] (Figure 1b). Bioanalytical assays can also be performed based on enzymatic reactions [55]. For instance, the amperometric signal generated by an enzymatic oxidation reaction, which depends on the concentration of the analyte, can be measured using an electronic interface.


System Integration - A Major Step toward Lab on a Chip.

Sin ML, Gao J, Liao JC, Wong PK - J Biol Eng (2011)

Test strip platform. (A) Schematic design of a test strip platform [51]. The sample fluid is drawn from the sample pad into the conjugate pad and membrane through the capillary action. (B) Immunoassays on the test strip. At the conjugate pad, nanoparticle-labeled-antibody rehydrate and bind with the specific antigen in the sample. Two different capturing antibodies are sprayed at the test line T and the control line C. At the test line, the antibody bind with the nanoparticle-labeled-antibody/antigen complex (positive assay) while the control line attach with the nanoparticle-labeled-antibody complex (proof of successful assay). (C) Image of commercially available pregnancy test strips [219].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117764&req=5

Figure 1: Test strip platform. (A) Schematic design of a test strip platform [51]. The sample fluid is drawn from the sample pad into the conjugate pad and membrane through the capillary action. (B) Immunoassays on the test strip. At the conjugate pad, nanoparticle-labeled-antibody rehydrate and bind with the specific antigen in the sample. Two different capturing antibodies are sprayed at the test line T and the control line C. At the test line, the antibody bind with the nanoparticle-labeled-antibody/antigen complex (positive assay) while the control line attach with the nanoparticle-labeled-antibody complex (proof of successful assay). (C) Image of commercially available pregnancy test strips [219].
Mentions: The test stripe platform consists of fleeces, which can draw liquid through stripes using the capillary effect (Figure 1a). The sample liquid, such as urine and blood, reacts with the reactants pre-immobilized on the stripe. The capillary filling action can be influenced by the permeability, the roughness, the dimension, the surface properties, and the total number of capillaries inside the stripe [51]. The fleece can also serve as a sample filter, which is essential for processing many physiological and environmental samples. For example, in blood analysis, blood cells can be blocked from entering into the reaction chamber. This eliminates the need for centrifugal separation [52]. Adequate and precise incubation of the sample with the reactant is also required for reactions to occur. Incubation time can be controlled by slowing down the capillary flow with local modifications of the channel geometry and property [51]. It should be noted that metering of sample liquid in the test stripe is important for quantitative assay. To ensure the well defined amount of liquid has passed the detection zone, the start reservoir should be filled with enough sample liquid. The liquid flow stops automatically in the end reservoir when the whole piece of fleece is fully wetted with liquid. The detectable signal of the test stripe assay can be measured quantitatively by engineering interfaces or qualitatively by manual observation in the detection zone. For optical detection, the diagnostic section can be illuminated by a laser diode and the resulting fluorescence emission of the fluorescently labeled analytes can be detected by a photodiode [53,54]. For qualitative readout, the analytes can be bound to small gold nano particles or colored latex particles. Accumulation of the analytes at the detection zone can produce a readable signal [51] (Figure 1b). Bioanalytical assays can also be performed based on enzymatic reactions [55]. For instance, the amperometric signal generated by an enzymatic oxidation reaction, which depends on the concentration of the analyte, can be measured using an electronic interface.

Bottom Line: It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics.In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications.Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ 85721, USA. pak@email.arizona.edu.

ABSTRACT
Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.

No MeSH data available.