Image Analysis of a Lateral Flow Strip Sensor for the Detection of Escherichia coli O157:H7

Abstract

Purpose: This study was performed to develop a lateral flow strip sensor for the detection of pathogenic Escherichia coli O157:H7 in various samples. Also, feasibility of using an image analysis method to improve the interpretation of the strip sensor was evaluated. Methods: The lateral flow strip sensor has been fabricated based on nitrocellulose lateral-flow membrane. Colloidal gold and E. coli O157:H7 antibodies were used as a tag and a receptor, respectively. Manually spotted E. coli O157:H7 antibody and anti-mouse antibody on nitrocellulose membrane were used as test and control dots, respectively. Feasibility of the lateral flow strip sensor to detect E. coli O157:H7 were evaluated with serially diluted E. coli O157:H7 cells in PBS or food samples. Test results of the lateral flow strip sensor were measured with an image analysis method. Results: The intensity of the test dot started to increase with higher concentration of the cells were introduced. The sensitivities of the sensor were both 10 4 CFU/mL Escherichia coli O157:H7 spiked in PBS and in chicken meat extract, respectively. Conclusions: The lateral flow strip sensor and image analysis method could detect E. coli O157:H7 in 20 min, which is significantly quicker than conventional plate counting method.

Low-cost, open-source 3D printed antibody dispenser for development and small-scale production of lateral flow assay strips

“…In academia, research labs often use pipettes and dispense 1–2 μL of antibodies onto the NC membrane due to the lack of accessibility to antibody dispensers. The method is good enough to validate new sensing modalities and concept validations, however, the resulting test signals appear as a circular or semicircular shape with uneven signal intensity [18] , [19] , [20] . Furthermore, dispensing performed by experimenters may result in variation of signal intensity because of inconsistent dispensing.…”

A Review on Lateral Flow Test Strip for Food Safety

“…Sandwich assay is used for relatively large pathogens that can have more than two different epitopes for an antibody pair, which include a labeled probe and a capture ligand. Kim et al (2013) utilized the sandwich assay format to develop a strip sensor for E. coli O157:H7 detection. In this study, they used gold nanoparticles as the labeling tag and antibodies against the recognition elements.…”

“…Image analysis systems have recently been developed for objective and quantitative interpretation of the LFTSs. Kim et al (2013) developed an image analysis system for LFTSs. The system acquired LFTS images with a CCD camera and analyzed the images to measure the peak area values of the test and the control zone.…”