Direct and fast detection of Alexandrium minutum algae by using high frequency microbalance

• We examine the direct detection of A. minutum algae using a new sensitive quartz crystal microbalance sensor.
• This immunosensor is highly specific to A. minutum.
• This immunosensor is able to quantify living or frozen whole cells.
• The fast and easy detection of toxic phytoplankton using microbalance was evaluated and discussed.

In this paper, a simple detection of a toxic algae, Alexandrium minutum, was developed using highly sensitive quartz crystal microbalance. In terms of performance, compared with other conventional analytical tools, the main interest of our immunosensor is based on a fast and direct detection of these living cells. This system requires the use of one monoclonal antibody directed against the surface antigen of A. minutum. We demonstrate that the whole living and motile algae are caught and detected. The high specificity of the biosensor is also demonstrated by testing several other dinoflagellate species. The frequency shift is correlated to the A. minutum cell concentration. This simple system is potentially promising for environmental monitoring purposes.