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complex formed during the immunoreaction at the sensor
surface, the change of the pH is one of the most common.
The use of 0.1 M NaOH as dissociation solution was assessed
by repeating a competitive assay on the same sensor
surface. Baseline close to the original was achieved after
the regeneration followed by a conditioning step with carrier
buffer.
The sensor performance as reported here is capable to
measure domoic acid at the established European regulatory
levels, furthermore the use of a monoclonal specific
antibody, already available in Abkem, together with the
possibility to use simultaneously a multiple channel flow
cell sensor makes very attractive the piezoelectric approach
as screening method for compliance with European food
legislation. This new set-up will be exploited in our laboratory.
Conclusions
In this paper we propose a simple and reliable approach of
a label-free piezoelectric sensor that could be used to analyse
domoic acid in food samples using a competitive format.
The immunosensor has been successfully tested with
domoic acid calibration solutions in the range of interest
for food safety application (considering a 1:4, v/v dilution
of the mussel extract). Matrix effects, mainly due to the
organic solvent content on the extracts, produced 9 % of
variation of the signal. Regeneration assays have shown
the possibility to reuse the modified surface after treatment
with 0.1 M NaOH. The sensor as described here is promising
as screening method for compliance with European
food legislation. Future work will address the application
to real samples, and the use of monoclonal antibody.
This work has been developed within the IFCA project
“Immunoprobes for food contamination analysis” (Project
N o GRD1 2001-40680) supported by the European Commission.
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