Sensors Project

MERHAB 2005-Targeted proposal: Rapid HAB detection instrument development and deployment.

Problem and Rationale: Demographic trends show strongly increasing numbers of people living in immediate proximity to the ocean increasing the risk of exposure to natural hazards. Paralytic shellfish poisoning (PSP) caused by consumption of shellfish that have fed on toxic algae remains a major health issue throughout North American coastal areas. The microalgae responsible for PSP are dinoflagellates, primarily Alexandrium ssp.. These algae produce potent neurotoxins that comprise the paralytic shellfish toxins (PSTs). Alexandrium can be toxic at such low numbers that the cells are not easily visible as blooms and water discoloration is not evident, making detection at early stages very important. Extensive monitoring efforts in coastal areas target the toxic producing algae as early warning systems to trigger more costly mouse bioassay toxin monitoring. Development of rapid, inexpensive and easy-to-use algal detection and enumeration devices would be a great boon for coastal monitoring managers, especially those states with extensive coastlines such as Maine.
Objectives: This project will focus on combining new molecular biology techniques with solid surfaces technologies to develop small, efficient instruments for use by water quality managers. These devices will be based on direct detection rather than chemical or enzymatic signal amplification.
Methods: This project will move detection of HAB organisms into a direct detection level that can more easily be either deployed on buoys or in hand held instruments for use by local groups. Synthetic DNA analogs will be used to enhance current technologies that are either impractical or inefficient using traditional DNA probes. The synthetic molecule, peptide nucleic acid (PNA), will be used as a capture probe for detection of Alexandrium. Several solid surface techniques will be explored for direct detection of the target organism, including surface plasma resonance (SPR), target mediated aggregation (TMA) and field effect transistor (FET)-based platforms. Hybridization time will be minimized using short low-voltage pulses within the hybridization chamber. The best of the platforms will be given to a coastal monitoring program for evaluation.
Significance: Direct detection of HAB organisms directly from field collected samples in a rapid (seconds), inexpensive (cents) and user-friendly format will represent a significant advance in our current HAB detection systems. The reduction of enzymes and other labile reagents will increase the shelf-life and further reduce costs. These platforms will allow non-scientists to monitor coastal waters in a cost effective manner and permit early warning systems to be eventually deployed onto buoys. Although this is primarily a proof-of concept project, successful completion will demonstrate utility of rapid platforms for non-scientists. These platforms will allow the addition of other organisms (both HAB and non-HAB) to the detectors through an electronic based microarray system.