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Portable microfluidic chip for detection of Escherichia coli in produce and blood.

Wang S, Inci F, Chaunzwa TL, Ramanujam A, Vasudevan A, Subramanian S, Chi Fai Ip A, Sridharan B, Gurkan UA, Demirci U - Int J Nanomedicine (2012)

Bottom Line: The microchip showed reliable capture of E. coli in PBS with an efficiency of 71.8% ± 5% at concentrations ranging from 50 to 4,000 CFUs/mL via lipopolysaccharide binding protein.The limits of detection of the microchip for PBS, blood, milk, and spinach samples were 50, 50, 50, and 500 CFUs/mL, respectively.The presented technology can be broadly applied to other pathogens at the POC, enabling various applications including surveillance of food supply and monitoring of bacteriology in patients with burn wounds.

View Article: PubMed Central - PubMed

Affiliation: Bio-Acoustic-MEMS in Medicine Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA.

ABSTRACT
Pathogenic agents can lead to severe clinical outcomes such as food poisoning, infection of open wounds, particularly in burn injuries and sepsis. Rapid detection of these pathogens can monitor these infections in a timely manner improving clinical outcomes. Conventional bacterial detection methods, such as agar plate culture or polymerase chain reaction, are time-consuming and dependent on complex and expensive instruments, which are not suitable for point-of-care (POC) settings. Therefore, there is an unmet need to develop a simple, rapid method for detection of pathogens such as Escherichia coli. Here, we present an immunobased microchip technology that can rapidly detect and quantify bacterial presence in various sources including physiologically relevant buffer solution (phosphate buffered saline [PBS]), blood, milk, and spinach. The microchip showed reliable capture of E. coli in PBS with an efficiency of 71.8% ± 5% at concentrations ranging from 50 to 4,000 CFUs/mL via lipopolysaccharide binding protein. The limits of detection of the microchip for PBS, blood, milk, and spinach samples were 50, 50, 50, and 500 CFUs/mL, respectively. The presented technology can be broadly applied to other pathogens at the POC, enabling various applications including surveillance of food supply and monitoring of bacteriology in patients with burn wounds.

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Related in: MedlinePlus

Evaluation of two different surface chemistry methods for E. coli detection on chip. (A) Assembly of the microfluidic chip consisting of PMMA, DSA, and glass cover. Actual image of the assembled microchip containing food dye for visualization. (B) Two antibody immobilization mechanisms were employed, ie, Protein G and NeutrAvidin based surface chemistry. In the first method, biotinylated anti-LBP antibody was immobilized on the microchannel surface via NeutrAvidin. Then, LBP was immobilized on anti-LBP antibody. In the second method, CD14, anti-LPS, or anti-flagellin antibodies was immobilized on the microchannel surface via Protein G. Only CD14 immobilization was illustrated and similar steps were followed for anti-flagellin and anti-LPS. (C) Detection of GFP-tagged E. coli on-chip. To validate the E. coli capture process, and quantify the on-chip concentration and capture efficiency of E. coli, these cells were identified under brightfield (100× magnification) and fluorescence microscopy. (i) Image of the control experiment without E. coli at 10× magnification under a fluorescence microscope. (ii) Image of the capture of GFP-tagged E. coli at 10× magnification under a fluorescence microscope. (iii) Image of the capture of GFP-tagged E. coli at 100× magnification under a fluorescence microscope. (iv) Image of the captured GFP-tagged E. coli at 100× magnification under bright field.Abbreviations: DSA, double-sided adhesive film; E. coli, Escherichia coli; GFP, green fluorescent protein; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; PBS, phosphate buffered saline; PMMA, poly(methyl methacrylate); POC, point-of-care; GMBS, N-(gamma-maleimidobutyryloxy) succinimide
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f2-ijn-7-2591: Evaluation of two different surface chemistry methods for E. coli detection on chip. (A) Assembly of the microfluidic chip consisting of PMMA, DSA, and glass cover. Actual image of the assembled microchip containing food dye for visualization. (B) Two antibody immobilization mechanisms were employed, ie, Protein G and NeutrAvidin based surface chemistry. In the first method, biotinylated anti-LBP antibody was immobilized on the microchannel surface via NeutrAvidin. Then, LBP was immobilized on anti-LBP antibody. In the second method, CD14, anti-LPS, or anti-flagellin antibodies was immobilized on the microchannel surface via Protein G. Only CD14 immobilization was illustrated and similar steps were followed for anti-flagellin and anti-LPS. (C) Detection of GFP-tagged E. coli on-chip. To validate the E. coli capture process, and quantify the on-chip concentration and capture efficiency of E. coli, these cells were identified under brightfield (100× magnification) and fluorescence microscopy. (i) Image of the control experiment without E. coli at 10× magnification under a fluorescence microscope. (ii) Image of the capture of GFP-tagged E. coli at 10× magnification under a fluorescence microscope. (iii) Image of the capture of GFP-tagged E. coli at 100× magnification under a fluorescence microscope. (iv) Image of the captured GFP-tagged E. coli at 100× magnification under bright field.Abbreviations: DSA, double-sided adhesive film; E. coli, Escherichia coli; GFP, green fluorescent protein; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; PBS, phosphate buffered saline; PMMA, poly(methyl methacrylate); POC, point-of-care; GMBS, N-(gamma-maleimidobutyryloxy) succinimide

Mentions: The microfluidic device was fabricated as previously reported.18,24,25 The device was designed with dimensions of 22 mm × 60 mm with three parallel microchannels. To assemble this device, poly(methyl methacrylate) (PMMA) (1.5 mm thick; McMaster Carr, Atlanta, GA) and double-sided adhesive film (DSA) (50 μm thick; iTapestore, Scotch Plains, NJ) were cut using a laser cutter (Versa Laser™, Scottsdale, AZ). The PMMA base and a glass cover slip were then assembled via the DSA. In the assembled E. coli detection device, three microchannels (with dimensions of 50 mm × 4 mm × 50 μm in the DSA layer) were formed with an inlet and outlet (0.565 mm in diameter) at each end of the channels in the DSA layer. Before assembling the chip, glass cover was cleaned with ethanol using sonication. Then, it was washed with distilled water and dried under nitrogen gas. After cleaning steps, the glass cover was plasma treated for 60 seconds. Then, PMMA, DSA, and glass cover were assembled to form the complete microchip (Figure 2A).


Portable microfluidic chip for detection of Escherichia coli in produce and blood.

Wang S, Inci F, Chaunzwa TL, Ramanujam A, Vasudevan A, Subramanian S, Chi Fai Ip A, Sridharan B, Gurkan UA, Demirci U - Int J Nanomedicine (2012)

Evaluation of two different surface chemistry methods for E. coli detection on chip. (A) Assembly of the microfluidic chip consisting of PMMA, DSA, and glass cover. Actual image of the assembled microchip containing food dye for visualization. (B) Two antibody immobilization mechanisms were employed, ie, Protein G and NeutrAvidin based surface chemistry. In the first method, biotinylated anti-LBP antibody was immobilized on the microchannel surface via NeutrAvidin. Then, LBP was immobilized on anti-LBP antibody. In the second method, CD14, anti-LPS, or anti-flagellin antibodies was immobilized on the microchannel surface via Protein G. Only CD14 immobilization was illustrated and similar steps were followed for anti-flagellin and anti-LPS. (C) Detection of GFP-tagged E. coli on-chip. To validate the E. coli capture process, and quantify the on-chip concentration and capture efficiency of E. coli, these cells were identified under brightfield (100× magnification) and fluorescence microscopy. (i) Image of the control experiment without E. coli at 10× magnification under a fluorescence microscope. (ii) Image of the capture of GFP-tagged E. coli at 10× magnification under a fluorescence microscope. (iii) Image of the capture of GFP-tagged E. coli at 100× magnification under a fluorescence microscope. (iv) Image of the captured GFP-tagged E. coli at 100× magnification under bright field.Abbreviations: DSA, double-sided adhesive film; E. coli, Escherichia coli; GFP, green fluorescent protein; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; PBS, phosphate buffered saline; PMMA, poly(methyl methacrylate); POC, point-of-care; GMBS, N-(gamma-maleimidobutyryloxy) succinimide
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3368510&req=5

f2-ijn-7-2591: Evaluation of two different surface chemistry methods for E. coli detection on chip. (A) Assembly of the microfluidic chip consisting of PMMA, DSA, and glass cover. Actual image of the assembled microchip containing food dye for visualization. (B) Two antibody immobilization mechanisms were employed, ie, Protein G and NeutrAvidin based surface chemistry. In the first method, biotinylated anti-LBP antibody was immobilized on the microchannel surface via NeutrAvidin. Then, LBP was immobilized on anti-LBP antibody. In the second method, CD14, anti-LPS, or anti-flagellin antibodies was immobilized on the microchannel surface via Protein G. Only CD14 immobilization was illustrated and similar steps were followed for anti-flagellin and anti-LPS. (C) Detection of GFP-tagged E. coli on-chip. To validate the E. coli capture process, and quantify the on-chip concentration and capture efficiency of E. coli, these cells were identified under brightfield (100× magnification) and fluorescence microscopy. (i) Image of the control experiment without E. coli at 10× magnification under a fluorescence microscope. (ii) Image of the capture of GFP-tagged E. coli at 10× magnification under a fluorescence microscope. (iii) Image of the capture of GFP-tagged E. coli at 100× magnification under a fluorescence microscope. (iv) Image of the captured GFP-tagged E. coli at 100× magnification under bright field.Abbreviations: DSA, double-sided adhesive film; E. coli, Escherichia coli; GFP, green fluorescent protein; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; PBS, phosphate buffered saline; PMMA, poly(methyl methacrylate); POC, point-of-care; GMBS, N-(gamma-maleimidobutyryloxy) succinimide
Mentions: The microfluidic device was fabricated as previously reported.18,24,25 The device was designed with dimensions of 22 mm × 60 mm with three parallel microchannels. To assemble this device, poly(methyl methacrylate) (PMMA) (1.5 mm thick; McMaster Carr, Atlanta, GA) and double-sided adhesive film (DSA) (50 μm thick; iTapestore, Scotch Plains, NJ) were cut using a laser cutter (Versa Laser™, Scottsdale, AZ). The PMMA base and a glass cover slip were then assembled via the DSA. In the assembled E. coli detection device, three microchannels (with dimensions of 50 mm × 4 mm × 50 μm in the DSA layer) were formed with an inlet and outlet (0.565 mm in diameter) at each end of the channels in the DSA layer. Before assembling the chip, glass cover was cleaned with ethanol using sonication. Then, it was washed with distilled water and dried under nitrogen gas. After cleaning steps, the glass cover was plasma treated for 60 seconds. Then, PMMA, DSA, and glass cover were assembled to form the complete microchip (Figure 2A).

Bottom Line: The microchip showed reliable capture of E. coli in PBS with an efficiency of 71.8% ± 5% at concentrations ranging from 50 to 4,000 CFUs/mL via lipopolysaccharide binding protein.The limits of detection of the microchip for PBS, blood, milk, and spinach samples were 50, 50, 50, and 500 CFUs/mL, respectively.The presented technology can be broadly applied to other pathogens at the POC, enabling various applications including surveillance of food supply and monitoring of bacteriology in patients with burn wounds.

View Article: PubMed Central - PubMed

Affiliation: Bio-Acoustic-MEMS in Medicine Laboratory, Center for Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA.

ABSTRACT
Pathogenic agents can lead to severe clinical outcomes such as food poisoning, infection of open wounds, particularly in burn injuries and sepsis. Rapid detection of these pathogens can monitor these infections in a timely manner improving clinical outcomes. Conventional bacterial detection methods, such as agar plate culture or polymerase chain reaction, are time-consuming and dependent on complex and expensive instruments, which are not suitable for point-of-care (POC) settings. Therefore, there is an unmet need to develop a simple, rapid method for detection of pathogens such as Escherichia coli. Here, we present an immunobased microchip technology that can rapidly detect and quantify bacterial presence in various sources including physiologically relevant buffer solution (phosphate buffered saline [PBS]), blood, milk, and spinach. The microchip showed reliable capture of E. coli in PBS with an efficiency of 71.8% ± 5% at concentrations ranging from 50 to 4,000 CFUs/mL via lipopolysaccharide binding protein. The limits of detection of the microchip for PBS, blood, milk, and spinach samples were 50, 50, 50, and 500 CFUs/mL, respectively. The presented technology can be broadly applied to other pathogens at the POC, enabling various applications including surveillance of food supply and monitoring of bacteriology in patients with burn wounds.

Show MeSH
Related in: MedlinePlus