Multiplex biotoxin surface plasmon resonance method for marine biotoxins in algal and seawater samples

Abstract

A multiplex surface plasmon resonance (SPR) biosensor method for the detection of paralytic shellfish poisoning (PSP) toxins, okadaic acid (and analogues) and domoic acid was developed. This method was compared to enzyme-linked immunosorbent assay (ELISA) methods. Seawater samples (n=256) from around Europe were collected by the consortia of an EU project MIcroarrays for the Detection of Toxic Algae (MIDTAL) and evaluated using each method. A simple sample preparation procedure was developed which involved lysing and releasing the toxins from the algal cells with glass beads followed by centrifugation and filtering the extract before testing for marine biotoxins by both multi-SPR and ELISA. Method detection limits based on IC20 values for PSP, okadaic acid and domoic acid toxins were 0.82, 0.36 and 1.66 ng/ml, respectively, for the prototype multiplex SPR biosensor. Evaluation by SPR for seawater samples has shown that 47, 59 and 61 % of total seawater samples tested positive (result greater than the IC20) for PSP, okadaic acid (and analogues) and domoic acid toxins, respectively. Toxic samples were received mainly from Spain and Ireland. This work has demonstrated the potential of multiplex analysis for marine biotoxins in algal and seawater samples with results available for 24 samples within a 7 h period for three groups of key marine biotoxins. Multiplex immunological methods could therefore be used as early warning monitoring tools for a variety of marine biotoxins in seawater samples.

Distribution, occurrence and biotoxin composition of the main shellfish toxin producing microalgae within European waters: A comparison of methods of analysis

“…The multitoxin SPR biosensor was optimised and discussed in full in previous research paper (McNamee et al, 2013). Briefly, the multitoxin SPR sensor chip was optimised on the prototype multiplex SPR biosensor.…”

“…Multitoxin SPR shows cross-reactivity of 68 % and 65 % for DTX1 and DTX2 compared to 78 % and 2.6 % for these two analogues by ELISA (Dubois et al, 2010;McNamee et al, 2013 for okadaic acid (due to LOD of 2.5 ng/ml) except for those from IEO (Spain). Results for the Spanish samples are very similar across the three testing platforms probably because the level of okadaic acid in the samples was much higher and therefore sensitivity was not an issue.…”

“…This reflects the number of positive samples by each detection method (Figure 1). Differences observed can be attributed to the LODs and cross-reactivity profiles of the antibodies used in the multitoxin SPR and ELISAs (Dubois et al, 2010;McNamee et al, 2013). The percentage of toxic samples by multitoxin SPR was considerably less for many partners except for Spain (IEO) and Ireland (NUIG), possibly because the levels of saxitoxin were much higher in these areas and so sensitivity was not an issue.…”

“…The multitoxin SPR biosensor encompasses three of the most commonly detected biotoxin groups in European waters; saxitoxin (and analogues), okadaic acid (including DTX1/DTX2) and domoic acid (McNamee et al, 2013). For phytoplankton species identification a RNA microarray was designed using rRNA probes for the identification of potentially harmful species (Barra et al, 2014;Dittami et al, 2013;Edvardsen et al, 2013;Kegel et al, 2013;McCoy et al, 2013;Taylor et al, 2013).…”

A roadmap for hazard monitoring and risk assessment of marine biotoxins on the basis of chemical and biological test systems

“…Recently, a solid-phase inhibition immunoassay was introduced with a detection range of 2.2 to 19.7 ng Stxequiv./ml (Fraga et al, 2012). A multiplex biotoxin surface plasmon resonance method was introduced for detection of marine biotoxins in algae and water, for which a lOD of 0.82 ng Stxequiv./ml has been reported (McNamee et al, 2012). Another approach for a rapid competitive assay -a fluorescence planar waveguide biosensor -for PSP toxins in marine algae revealed a lOD of 12 pg Stxequiv./ml and a CCβ of 20 pg Stxequiv./ml (Meneely et al, 2013).…”