Lab-on-a-Chip for Field Escherichia Coli Assays: Long-Term Stability of Reagents and Automatic Sampling System

Abstract

A field lab-on-a-chip system was constructed to detect mouse immunoglobulin G (mIgG; model protein target) and Escherichia coli (E. coli; model microorganism target) by using light scattering detection of particle immunoagglutination. The antibodies to these targets were conjugated to the submicron particles by covalent binding, and their long-term stability was evaluated. Antibodyconjugated particles were able to be stored in a 4 C refrigerator for at least 4 weeks and to be lyophilized as a powder form for the storage in room temperature. The optimum antibody coverage on the particles was 50% for mIgG and 100% for E. coli in terms of assay sensitivity and long-term storage of reagents. Lab-on-a-chip device was fabricated from acrylic plate using an industrial-grade milling machine eliminating the need for photolithography and internal or external pumping. An automatic sampling system was constructed using drip emitters, such that the system can be connected to a pressurized water pipe for detecting E. coli. The automatic sampling system generated the same volume of droplets (70 mL) regardless of pressure. The developed system was successfully tested for E. coli presence in field water samples. The system can potentially be connected to pressurized pipe networks for drinking, processing, irrigation, and wastewater.

Rapid and Sensitive Detection of H1N1/2009 Virus from Aerosol Samples with a Microfluidic Immunosensor

“…Anti-H1 (R01419; Meridian Life Science, Saco, ME) was conjugated to the 920-nm highly carboxylated polystyrene beads (10.3 Å 2 parking area per surface carboxyl group; Bangs Laboratories, Fishers, IN) by covalent binding, as described in previous research. 16 Anti-H1 specifically binds to the type 1 hemagglutinin protein on the surface of H1N1 virus capsid. We have also tested anti-N1 (type 1 neuraminidase protein) but found their binding strength (as determined by the slope of a standard curve) was inferior to that of anti-H1.…”

Lab-on-a-Chip Pathogen Sensors for Food Safety

“…In the past, this has been detected visually, with the detection limit being the point at which agglutinates precipitate and become visible; however, measuring the immunoagglutination via forward light scattering in a lab-on-a-chip is more appropriate [ 48 ], as agglutinated submicron or nanoparticles are not required to precipitate out of solution for a positive signal [ 49 , 50 ]. Yoon's research group has primarily investigated LIA in lab-on-a-chip [ 51 – 56 ]. Particles with a diameter near the wavelength of visible light were used, i.e.…”

Emerging (Bio)Sensing Technology for Assessing and Monitoring Freshwater Contamination - Methods and Applications

“…Cholera, typhoid fever, bacillary dysentery, leptospirosis and gastroenteriris are some examples of waterborne diseases caused by Vibrio cholera, Salmonella typhi, Shigella spp., Leptospira spp., and Enteropathogenic Escherichia coli [EPEC] (Ashbolt, 2004). Table 1 resumes the latest screening methods for waterborne bacteria; capture and detection methods, limit of detection [LOD] and range of detection are compared (Baudart & Lebaron, 2010;Bharadwaj et al, 2011;Bruno et al, 2010;Chen et al, 2008;Duplan et al, 2011;Fu et al, 2010;Geng et al, 2011;Guven et al, 2011;Huang et al, 2008Huang et al, , 2011Karsunke et al, 2009;Kwon et al, 2010;Li et al, 2011A;Luo et al, 2010;Miranda-Castro et al, 2009;Park et al 2008;Sun et al, 2009;Wilbeboer et al, 2010;Wolter et al, 2008;Yoon et al, 2009;Yu et al, 2009;Xue et al, 2009). …”