Improving Biosecurity in Aquaculture using High Speed, Low cost, Lab on a Chip Micro-Cytometry for the Surveillance of Harmful Algal Blooms.

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This project will develop a new seawater analysis tool to improve the biosecurity of shellfisheries, which are vulnerable to contamination with algal bio-toxins (poisons) that are associated with harmful algal blooms. It will do this by re-engineering an existing Lab on Chip (LOC) micro-cytometer that counts and characterises single cells as they flow in single file in a channel less than 0.1mm wide. It can count and discriminate specific algal cell types, including bio-toxin producing species native to the UK, directly in seawater samples. This technology represents a low cost, miniaturised alternative to existing cytometers with enhanced functionality and capability. It has the potential to significantly improve species resolution by generating synchronous fluorescence and electrical impedance measurements, the latter being absent from current systems. The generation of unique cytometric profiles for target species based on both parameters increases the accuracy with which they can be discriminated within complex samples containing non-target species with similar morphological characteristics. Other advantages of the system include the absence of a sheath flow (clean water used in standard cytometers to control cell position in the channel), which improves throughput, eliminates the need to carry or generate clean water and facilitates, where necessary, the periodic unblocking of the flow channel (by flow inversion). The project objectives were conceived with, and refined by one of our "end-users" and a project sub-contractor, the Centre for Environment, Fisheries and Aquaculture Sciences (Cefas), with whom we have a strong, long-standing collaborative relationship. Cefas carry out statutory harmful algal bloom / algal bio-toxin surveillance in line with current European Union regulations regarding the quality of shellfish produced for human consumption. This entails periodic monitoring of water samples for harmful algal species, and where necessary acts as an early warning system that stimulates the increased sampling and analysis of shellfish flesh for algal bio-toxins. Currently, water samples delivered to a centralised laboratory are analysed by microscopy. This process is time consuming and delays intervention, leading to an increased risk to human health and potential cost to the industry from loss of shellfish product. Accordingly, rapid and near-real time analysis systems are required to aid / complement microscopic analysis. To address this, the project will deliver a portable, bench-top LOC micro-cytometer for the rapid counting and discrimination of specific algal cell types in seawater samples. The system will be capable of being operated by non-specialist personnel using automated data analysis software and will be used by our project partners, Offshore Shellfish Ltd and the Environment Agency, as an in situ early warning tool, and our end-user and sub-contractor, Cefas, to complement existing water sample analysis (using microscopy), with a view to reducing analysis time. The project outputs will also complement existing algal surveillance programmes using satellite imaging by providing in situ data, uninterrupted by cloud cover. It will deliver impact by facilitating timely intervention, directly leading to economic gain and reduction in public health risks. The outputs from the project will underpin the future development of a robust, deployable system that can be operated in situ including offshore. This will provide near real-time analysis of shellfisheries waters, obviating the need to collect samples from high risk locations. Keywords: Harmful Algal Bloom (HAB); micro-cytometer; Lab on a Chip (LOC); Micro-systems; Biosecurity; Shellfisheries; Aquaculture