Biosensor-based Methods for Detection of Microcystins as Early Warning Systems

Sammanfattning: Popular Abstract in English Global invasion of our precious watercourses by cyanobacteria poses great threat to human- and animal health by deteriorating water systems. In fact, this problem is not likely to be solved in the near future as cyanobacteria are associated with pollution of waterways. Consequently, water sources are subject to contamination by natural toxins produced by abundant growth of cyanobacterial blooms all over the world. The produced toxins, which may be present at low levels without harm to humans or animals, can rapidly increase to become a dire health risk under certain environmental conditions. In addition, the rising global temperatures intensify the situation and excessive nutrient loading of watercourses through increased human activities by the expanding global populations, resulting in growth promotion of the potent toxin-producing blooms in surface waters. In most cases, surface water supplies potable water to communities and hence any bloom expansion raises concern over human health safety. Communities with resource-limited settings often depend directly on water sources with limited treatment infrastructure available. As such, the presence of these potent cyanotoxins especially microcystins limit the use of the water. Although potent microcystins are known to occur in surface waters, there is still no known general method for their removal from contaminated water when the concentration increases and reaches lethal levels, thus reflecting a need for emergent mitigations. Several detection methods are available for detecting microcystins but are neither sensitive enough to measure low concentrations nor user-friendly. Therefore, the pressure to detect these toxins in trace amounts has led to increased research on development of analytical systems such as biosensors to overcome this problem. In this thesis, sensitive biosensors have been developed for microcystin detection. Biosensor configurations combined with the advances in nanotechnology result in platforms with improved detection sensitivities compared to traditional analytical methods. It is expected that this new approach will dramatically reduce the analysis time, thereby reducing overall analysis costs without any loss of sensitivity and precision. These systems are made into small portable devices that can be taken to the site of contamination and quickly analyze the water. Mass production of such detection devices could help the communities out there who are in desperate need for clean and microcystin-free water.