Rapid Electrochemical Immunoassays for Low Cost, Multiplex Detection of Food Pathogens using Capillary Driven Microfluidic Devices
Abstract
Foodborne illness costs Soldiers an average of 3 workdays per year resulting in $900 million in lost productivity 1,2. Current techniques to detect foodborne pathogens such as molecular diagnostics and culture counting require long wait times, centralized labs, complex instruments, and trained personnel. We have developed a capillary microfluidic device for rapid (1-2 hrs), low-cost (approx. $2-10 per test) electrochemical detection of pathogenic bacteria. Prior work demonstrated detection of Salmonella sp. at 640 CFU/mL within 2 hrs in milk using an electrochemical immunoassay. This consisted of magnetic extraction and concentration utilizing functionalized magnetic beads. The remaining solution was incubated with a biotinylated secondary antibody and a streptavidin tagged electrically active enzyme. Finally, the mixture was added to a thermoplastic electrode and an electrically active substrate for analysis with a portable potentiostat. We are investigating methods to improve sample treatment and multiplexing detection of bacteria. Sample pre-treatment uses capillary-driven immunomagnetic filtration to concentrate and extract target bacteria instead of manual pipetting. The captured antibody functionalized magnetic microbeads then provide a platform for an enzymatic sandwich assay. The electrochemical substrates remain physically separated throughout the process, allowing simultaneous detection of multiple bacteria. The microfluidic-driven nature of the device facilitates rapid turnaround, allowing it to run at a point-of-need timescale, and provides a user-friendly experience to enable use by an untrained end user. The development methods are amenable to diverse targets of interest (bacteria, toxin, virus, protozoa/cyst) and sample types (food, environmental samples, and clinical samples) by adapting the antibodies or recognition elements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 14, 2023
- Accession Number
- AD1225180
Entities
People
- Charles Henry
- Cody Carrell
- Jason Boes
- Michael S Wiederoder
- Shannon K. Mcgraw-manza
Organizations
- Colorado State University
- United States Army