In spite of the urgent need for better tools, automated, in situ methods for the determination of the presence, abundance and activity of marine microbes are still in the development stages. The Capillary Waveguide Biosensor (CWB) will potentially make possible long-term, in situ, unattended detection of microorganisms and monitoring of microbial processes. This is a renewal of the PI's EAGER proposal. They were able to complete two of the three tasks originally proposed. With this addition funding they will complete the third task, which was to optimize hybridization protocols and achieve a dynamic range satisfactory for use in real-world studies.
The potential for training students at graduate, undergraduate and high school levels in this project is particularly interesting and exciting, because it will offer students the opportunities to cross-train in microbial ecology and engineering. Also, education and training of minorities and exposure of the general public to science are two other likely benefits of this project. Participation of C-MORE students is great. If molecular techniques are going to be used more frequently in the future, students are going to have to get used to the technology.
The Capillary Waveguide Biosensor (CWB) is designed as an analytical module for the MBARI Environmental Sample Processor (ESP), which filters large volumes of water, concentrates cells, and can pre-process them before delivery to downstream analytical modules. The CWB module measures the abundance of DNA that can be used to identify the type of microorganisms present in a water sample. Although our own interests lie primarily with addressing challenging ecological questions, the CWB analytical module has many other potential uses. For example, the capacity to examine microbial populations with a reusable sensor has enormous potential benefit for water quality management and the seafood industry, both economically and with respect to food safety. The purpose of this project was to increase the sensitivity of the CWB to the point that we would be able to detect microorganisms of interest at their natural abundances in seawater, ideally at abundances comprising 1% or less of the natural microbial community. During our work to increase sensitivity, we learned that more work is needed to obtain measurements that are reproducible over long periods and many samples. We have solved many of the problems we encountered. For example, we now have a long-lasting biosensor that can be reused for at least 100 measurements. We made considerable headway in understanding the many factors that can cause measurements to vary between samples. We remain confident that the capillary waveguide biosensor platform is still worthy of further consideration as a viable sensor of genetic material in the ocean environment.