Optically Paired Microfluidics for E. coli Detection

Abstract

Escherichia coli is a diverse bacterium that inhabits the lower intestine of warm-blooded animals. While most strains are harmless, some are pathogenic and can cause food poisoning, intestinal damage, and other illness. Annually, 380,000 people die from E. coli-triggered diarrhea. Our design team aims to create a low-cost, optically-paired paper microfluidic sensor that detects E. coli presence and concentration in water samples. A paper microfluidic assay platform was chosen for its properties of being inexpensive, biodegradable, and nontoxic. The paper microfluidic strips are imbued with antibody-conjugated latex particles. These particles bond with each other in the presence of E. coli, which allows for optical detection using the changed intensity of light reflected from the surface of the chip. Our model has a sensor device where the user collects a water sample, dips a paper microfluidic strip into it, then inserts that strip into an optical detector that uses light scattering to quantify E. coli concentration. The sensor microcontroller and components will be housed in a durable 3D-printed casing that optimally positions the optical setup and feeds results to a compact LCD display. This sensor will be flexible for a range of microfluidic systems.