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Development of a plastic-based microfluidic immunosensor chip for detection of H1N1 influenza.

Lee KG, Lee TJ, Jeong SW, Choi HW, Heo NS, Park JY, Park TJ, Lee SJ - Sensors (Basel) (2012)

Bottom Line: A fluorescent dye-labeled antibody (Ab) was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique.For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip.This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanobio Integration & Convergence Engineering (NICE), National NanoFab Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-806, Korea. kglee@nnfc.re.kr

ABSTRACT
Lab-on-a-chip can provide convenient and accurate diagnosis tools. In this paper, a plastic-based microfluidic immunosensor chip for the diagnosis of swine flu (H1N1) was developed by immobilizing hemagglutinin antigen on a gold surface using a genetically engineered polypeptide. A fluorescent dye-labeled antibody (Ab) was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique. For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip. This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device.

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Related in: MedlinePlus

Schematic illustration for (A) the fabrication of COC-based microfluidic chip, (B) detailed features of the chip, (C) GBP-H1a fusion protein immobilization step and Cy3-labeled Ab reaction in the chip.
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f1-sensors-12-10810: Schematic illustration for (A) the fabrication of COC-based microfluidic chip, (B) detailed features of the chip, (C) GBP-H1a fusion protein immobilization step and Cy3-labeled Ab reaction in the chip.

Mentions: The plastic-based microfluidic devices were fabricated by an injection molding technique. The microchannels-embedded master mold was obtained by a milling technique, and it was used for casing the microfluidic devices. In this case, COC was chosen as a substrate material to produce the device due to its great advantages over the other thermoplastic polymers in terms of optical, physical and chemical properties and biocompatibility. The total cycle time of the microinjection molding process took less than 1 min to replicate the COC substrate. After location of the master mold in the injection mold machine, COC was injected through the nozzle, and the microfluidic device was released from the mold. The production process and conditions are similar to the previous research which demonstrated various microinjection conditions to form microstructures [17]. Holes of 1 mm in diameter for an inlet and outlet ports were punched to load the sample and buffer solutions into the microchannels. As shown in Figure 1, the channel depths are 200 and 500 μm with 450 μm in width, respectively. The diameter of the detection chamber is 1 mm, and it was coated with chromium and gold by sputtering for the immobilization of GBP-H1a fusion protein. The design and fabrication process of microfluidic device are described in Figure 1(A). The key features of microstructures including welding lines, gold deposition on detection chamber, and backflow prevention structures are schematically demonstrated in Figure 1B. Previously, thermal bonding method has been popular to bond plastic-based microfluidic device. However, this method requires high temperature and takes too much time to bond it. Recently, an ultrasonic bonding method has been developed as an alternative solution to the thermal bonding. However, welding line is essential for bonding between plastic chips in this technique. In this experiment, we carefully designed the welding lines as shown in red color in Figure 1(B), and these lines were melted during the ultrasonic bonding process for the sealing of the chips. After coating of gold, two COC plates were placed on the ultrasonic bonder (2,000X, Branson) and set the bonder in time mode with weld frequency of 20 kHz. After the setting of the mode, the COC was bonded as following conditions: (1) 800 Pa weld pressure, (2) 0.2 s of weld time, (3) 75% of amplitude, (4) 10 s of hold time, (5) 1.5 kPa of hold pressure. Occasionally, backflow of the buffer or target solutions occurs in microfluidic channels during the injection to cause a contamination problem. Therefore, there would be required a unique microstructure in a microchannel to prevent backflow of solution and contamination of microchannel. Among various methods, two different channel depths were applied into this device as shown in Figure 1(B). This method was worked properly due to the pressure difference in the microchannel to prevent the backflow.


Development of a plastic-based microfluidic immunosensor chip for detection of H1N1 influenza.

Lee KG, Lee TJ, Jeong SW, Choi HW, Heo NS, Park JY, Park TJ, Lee SJ - Sensors (Basel) (2012)

Schematic illustration for (A) the fabrication of COC-based microfluidic chip, (B) detailed features of the chip, (C) GBP-H1a fusion protein immobilization step and Cy3-labeled Ab reaction in the chip.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472858&req=5

f1-sensors-12-10810: Schematic illustration for (A) the fabrication of COC-based microfluidic chip, (B) detailed features of the chip, (C) GBP-H1a fusion protein immobilization step and Cy3-labeled Ab reaction in the chip.
Mentions: The plastic-based microfluidic devices were fabricated by an injection molding technique. The microchannels-embedded master mold was obtained by a milling technique, and it was used for casing the microfluidic devices. In this case, COC was chosen as a substrate material to produce the device due to its great advantages over the other thermoplastic polymers in terms of optical, physical and chemical properties and biocompatibility. The total cycle time of the microinjection molding process took less than 1 min to replicate the COC substrate. After location of the master mold in the injection mold machine, COC was injected through the nozzle, and the microfluidic device was released from the mold. The production process and conditions are similar to the previous research which demonstrated various microinjection conditions to form microstructures [17]. Holes of 1 mm in diameter for an inlet and outlet ports were punched to load the sample and buffer solutions into the microchannels. As shown in Figure 1, the channel depths are 200 and 500 μm with 450 μm in width, respectively. The diameter of the detection chamber is 1 mm, and it was coated with chromium and gold by sputtering for the immobilization of GBP-H1a fusion protein. The design and fabrication process of microfluidic device are described in Figure 1(A). The key features of microstructures including welding lines, gold deposition on detection chamber, and backflow prevention structures are schematically demonstrated in Figure 1B. Previously, thermal bonding method has been popular to bond plastic-based microfluidic device. However, this method requires high temperature and takes too much time to bond it. Recently, an ultrasonic bonding method has been developed as an alternative solution to the thermal bonding. However, welding line is essential for bonding between plastic chips in this technique. In this experiment, we carefully designed the welding lines as shown in red color in Figure 1(B), and these lines were melted during the ultrasonic bonding process for the sealing of the chips. After coating of gold, two COC plates were placed on the ultrasonic bonder (2,000X, Branson) and set the bonder in time mode with weld frequency of 20 kHz. After the setting of the mode, the COC was bonded as following conditions: (1) 800 Pa weld pressure, (2) 0.2 s of weld time, (3) 75% of amplitude, (4) 10 s of hold time, (5) 1.5 kPa of hold pressure. Occasionally, backflow of the buffer or target solutions occurs in microfluidic channels during the injection to cause a contamination problem. Therefore, there would be required a unique microstructure in a microchannel to prevent backflow of solution and contamination of microchannel. Among various methods, two different channel depths were applied into this device as shown in Figure 1(B). This method was worked properly due to the pressure difference in the microchannel to prevent the backflow.

Bottom Line: A fluorescent dye-labeled antibody (Ab) was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique.For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip.This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device.

View Article: PubMed Central - PubMed

Affiliation: Center for Nanobio Integration & Convergence Engineering (NICE), National NanoFab Center, 291 Daehak-ro, Yuseong-gu, Daejeon 305-806, Korea. kglee@nnfc.re.kr

ABSTRACT
Lab-on-a-chip can provide convenient and accurate diagnosis tools. In this paper, a plastic-based microfluidic immunosensor chip for the diagnosis of swine flu (H1N1) was developed by immobilizing hemagglutinin antigen on a gold surface using a genetically engineered polypeptide. A fluorescent dye-labeled antibody (Ab) was used for quantifying the concentration of Ab in the immunosensor chip using a fluorescent technique. For increasing the detection efficiency and reducing the errors, three chambers and three microchannels were designed in one microfluidic chip. This protocol could be applied to the diagnosis of other infectious diseases in a microfluidic device.

Show MeSH
Related in: MedlinePlus