A system with the capability to rapidly extract and concentrate small quantities of bacterial contaminates dispersed in large environmental samples.


Food borne diseases caused by pathogens have devastating impacts on public health and consumer safety assurance. For example, in the United States, where detection technology can be considered advanced and common, each year an estimated 48 million Americans are stricken ill as the result of one food-borne pathogen or another (e.g., listeria, E. coli, salmonella), equivocating to an annual 55.5 billion dollar industry. Early detection and routine surveillance is of paramount importance for effective management of food or waterborne infectious disease.

One of the most direct ways to eradicate contamination is to be able to detect pathogens on site, and in the field using point-of-care (POC) testing. However, detecting microbial pathogens directly in the environment, can be like finding a needle in a haystack. Trace contaminations of pathogens on food and in the environment remain notoriously difficult to detect, eluding even the most sensitive molecular methods. Gene-based assays typically test sample volumes of 1-5 μL, so that a single replicate of even a robust assay is statistically unlikely to detect pathogens at levels below 103 colony forming units/mL. This limit exceeds regulatory levels for many high-consequence pathogens.

Contemporary methods such as centrifugation, immunomagnetic separation (IMS), size‑fractionation, and filtration are commonly used to separate or concentrate target organisms upstream of detection to enhance sensitivity; however, these technologies are costly and not easily adaptable for field application. Virtually every application in the food and agriculture industries can benefit from the development of inexpensive, flexible and portable sample preparation systems that can concentrate and recover trace biological contamination from varying sample types at different scales.

Researchers at the University of Hawai‘i College of Tropical Agriculture and Human Resources have developed a portable, Android-based electroflotation system for rapid concentration of suspended particles such as bacteria. Portable molecular diagnostics bring detection and diagnostics out of the lab and into the field, enabling POC testing which facilitates quicker responses and more specific treatments.

Electroflotation separates suspended solids from liquid media using the adhesive and buoyant forces of electrolytically generated gaseous microbubbles. These 20-40 um sized bubbles are ideal to indiscriminately extract any particles ranging from the size of 0.5 to 200 um (i.e., viruses, parasites, bacteria) present in the sample matrix.

Biological contaminants adhered to the microbubbles concentrate at the chamber surface. Once concentrated, the biological contaminants are displaced from the collection chamber through a dispensing tube where it is recovered in user defined volume fractions.

Key Benefits

Rapid POC sample preparation
Sample to results in 1‑3 hours
Full process, field deployable bio‑lab
Self-contained system
Eliminates requirement for traditional laboratory facility
Interfaces wirelessly to a smart phone
Battery powered (rechargeable)
Fully Automated
Durable platinum coated titanium electrodes
Extremely portable
Over 98% cost savings compared to traditional methods


POC biological contamination detection for:
Food Safety
Agricultural rinsates
Water quality
Environmental sampling
Irrigation, flooding and agricultural run‑off
Gene based detection of trace contamination
In-field concentration of bacteria
Concentrate extremely small quantities of biological contaminants from large, dilute samples
Can be coupled to gene‑based molecular diagnostics for in‑field results in under 3 hours

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