Team:UChile Biotec/Description

Project description

BIMATOX

BiMaTox is a DNA aptazyme biosensor for different marine toxins that are produced during harmful algal blooms (HAB), also known as red tides. The main paralytic toxins produced during such events are Saxitoxin (STX), Brevetoxin-2 and Okadaic Acid. Of these, STX is the most-deadly, as it attacks the human nervous system by blocking sodium channels present in neurons, impeding synapse formation. The biosensor consists of a cell-free cellulose matrix device that displays a color in the presence of the toxin. The aptazymes will consist of a specific toxin aptamer connected to a horse radish peroxidase (HRP)-mimicking DNAzyme. When the toxin binds to its specific aptamer, the HRP activity of DNAzyme is triggered and produces the oxidation of a compound called ABTS, which generates a color that is readily visible to the human eye.

OUR MOTIVATION

Chile has a very extensive coastline. A significant portion of the national economy is related to marine resources, providing an important source of employment. Therefore, HAB causes significant social and environmental problems not only in Chile but also in other parts of the world. In 2016, Chile was affected by an unprecedented algal bloom that seriously damaged artisanal fishing in the south, particularly in Chiloé Island. This epidemic provoked many social protests by the local population, eager for answers and solutions. The standard method used to detect paralytic toxins in Chile is a mice bioassay, using injections of potentially-contaminated shellfish samples. Although this method is robust, it comes with a variety of problems such as: 1) elevated costs, 2) the use of thousands of mice and 3) a requirement for highly-trained professionals in certified laboratories. Considering that HABs will continue to occur, yet current screening methods are laborious and time-consuming, we were motivated to develop a simple early warning device for the detection of marine toxins.

Our BiMaTox is a rapid, reliable and accessible biosensor that will facilitate the detection of these toxins. Our synthetic biology device will be easy to use for people without highly-specialized training. We believe in reducing the time and costs associated with the current methods, and we expect to protect the health of people, and provide tools for the authorities for better and faster decision-making.

REFERENCES

These are the publications that leaded our investigation:

  • Busa, L., Maeki, M., Ishida, A., Tani, H. and Tokeshi, M. (2016). Simple and sensitive colorimetric assay system for horseradish peroxidase using microfluidic paper-based devices. Sensors and Actuators B: Chemical, 236, pp.433-441.
  • Golub, E., Albada, H., Liao, W., Biniuri, Y. and Willner, I. (2016). Nucleoapzymes: Hemin/G-Quadruplex DNAzyme–Aptamer Binding Site Conjugates with Superior Enzyme-like Catalytic Functions. Journal of the American Chemical Society, 138(1), pp.164-172.
  • Teller, C., Shimron, S. and Willner, I. (2009). Aptamer−DNAzyme Hairpins for Amplified Biosensing. Analytical Chemistry, 81(21), pp.9114-9119.
  • Zheng, X., Hu, B., Gao, S., Liu, D., Sun, M., Jiao, B. and Wang, L. (2015). A saxitoxin-binding aptamer with higher affinity and inhibitory activity optimized by rational site-directed mutagenesis and truncation. Toxicon, 101, pp.41-47.