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Development of a rRNA-biosensor for the detection of toxic algae (ALGADEC)

Final Report Summary - ALGADEC (Development of an rRNA-biosensor for the detection of toxic algae)

Algal blooms represent a serious public health and economic problem; however, no cost-effective device for the specific detection of toxic strains is yet available on the market. In addition, the implemented techniques are time consuming and costly, while some of them raise ethical questions regarding laboratory animals' exploitation.

Various methods are currently used for phytoplankton analysis. Among them, the use of molecular methods by means of genetic sequences is the only technique that renders algae definition possible. Electrochemical methods are also promising, since they represent an affordable solution that is easier to implement in comparison to other alternatives. Therefore, the formulation of a proposal combining differentiation at molecular level with an electrochemical reaction is an excellent option for quantitative, algae specific results.

In this context, the aim of the ALGADEC project was to develop a handheld device for the in situ analysis of toxic algae concentrations. The device consisted of a housed electric interface equipped with a data recording system and two external units, namely the fluidic cell and the heating chamber. This innovation was anticipated to predict dangerous concentrations of algae and, as a consequence, allow for corrective actions, support the economic well-being of small coastal communities and prevent potential economic losses in aquaculture and tourist industry. In addition, the state of the art European monitoring systems would be improved.

The methodology was based on deoxyribonucleic acid (DNA) testing which provided the ability to detect noxious algae under hybridisations or genetic evolutions. A specific quantification of ribosomal ribonucleic acid (rRNA) in a sample through electrochemical measurements was obtained by means of sandwich hybridisation. The central part of the sequence-specific electrochemical rRNA sensor consisted of a chip carrying three electrodes which, via the application of potential, created a current proportional to the concentration of peroxidase, which indirectly represented the amount of target rRNA. This signal also demonstrated a good correlation with cell counts from the water column. Sample pre-processing was necessary to obtain the required rRNA and could be completed within the proposed device.

The successfully developed ALGADEC biosensor was anticipated to have an impact on the European seafood industry. Furthermore, the product commercialisation would have a favourable effect on the involved small and medium enterprises (SMEs). Finally, given that the equipment was easy to operate and adaptable to various pathogen detection applications, it was addressed to various end users, including fish farmers, monitoring agencies and tourist administrations, hence it was of interest for a wide public.