About This Project

For commercial shellfish farmers and recreational hunters alike, marine biotoxins pose a significant threat to health and welfare. With this project, we aim to create an inexpensive and easy-to-use test kit for the detection of the small molecules auxin and theophylline using engineered yeast strains and DNA aptamers on a paper device. We hope that this project paves the way for a new class of biosensors capable of detecting a wide range of molecules, including the shellfish toxin okadaic acid.

Ask the Scientists

What is the context of this research?

Marine toxins are an increasing problem in Washington State waters. Produced in high concentrations by microorganisms during algae blooms, they are ingested by filter-feeding shellfish, causing illness and death in human consumers. Biotoxins are also difficult to detect; contrary to popular belief, algal blooms are not always the striking crimson of "red tides." Thus, blooms may not be discovered until after a poisoned shellfish is found.

The Washington State Department of Health and commercial shellfish farmers conduct periodic surveys of local beaches to catch contaminations early, but these methods are costly, time-consuming, and not always effective. This can especially pose a dilemma for individual shellfish hunters, who do not have the resources to screen their shellfish for toxins.

What is the significance of this project?

Our project aims to combine the emerging fields of synthetic biology and paper diagnostics to create an affordable, accessible, and accurate diagnostic test kit. While unable to use toxins directly at this early stage of the project, our "lab on a strip" will be a critical step forward in detection of small molecules and will later be applied to marine toxin detection. It will cut nearly 20 hours off the time needed to obtain results, allowing farmers to screen at a lower cost and empowering individual hunters to confirm the safety of their shellfish.

This is also the first project to attempt to grow yeast on a paper device, and if successful, could open the door to a wide range of similar biosensors. Such sensors would have applications in medicine, food, and the environment worldwide.

What are the goals of the project?

Our ultimate goal is to improve the safety of shellfish consumers worldwide. First, we a developed a paper microfluidic device that houses yeast, providing adequate nutrients for cell growth and freeze-dried for long-term storage. We then built a detection system for the plant hormone auxin in which yeast produce a color in response to an auxin input. In our second detection system, we used RNA aptamers to detect for theophylline, a small molecule that can be used to model common biotoxins.

After this, we aim to show that both detection pathways are viable on a paper-based platform and assemble working devices for detection of auxin and theophylline. Future work includes building a shellfish detection pathway for okadaic acid and submitting genetic parts to an open-source registry.