Development of a direct detection method for Alexandrium spp. Using surface plasmon resonance and peptide nucleic acid probes.

Marine dinoflagellates of the genus Alexandrium can produce dangerous amounts of paralytic shellfish toxins at such low cell densities that water discoloration often associated with harmful algal blooms is not always evident, making detection of blooms during early stages extremely important. Our research focuses on developing a new method of molecular detection for multiple species of Alexandrium using peptide nucleic acid (PNA) probes and surface plasmon resonance. Results thus far indicate that this method yields reliable detection of perfectly complimentary oligonucleotide sequences specific to A. fundyense, A. tamarense, A. catenella, and A. ostenfeldii with no detection of non-complimentary sequences, as well as very good discrimination between negative control PNA probes and Alexandrium-specific PNA probes. We have also been able to regenerate the probe layer on the sensor surface for use in multiple assays by removing the target DNA, making this method economical in the long run.