Cyanobacterial blooms cause local and global health issues by contaminating surface waters. Microcystins and nodularins are cyclic cyanobacterial peptide toxins comprising numerous natural variants. Most of them are potent hepatotoxins, tumor promoters, and at least microcystin-LR is possibly carcinogenic. In drinking water, the World Health Organization (WHO) recommended the provisional guideline value of 1 µg/L for microcystin-LR. For water used for recreational activity, the guidance values for microcystin concentration varies mostly between 4–25 µg/L in different countries. Current immunoassays or lateral flow strips for microcystin/nodularin are based on indirect competitive method, which are generally more prone to sample interference and sometimes hard to interpret compared to two-site immunoassays. Simple, sensitive, and easy to interpret user-friendly methods for first line screening of microcystin/nodularin near water sources are needed for assessment of water quality and safety. We describe the development of a two-site sandwich format lateral-flow assay for the rapid detection of microcystins and nodularin-R. A unique antibody fragment capable of broadly recognizing immunocomplexes consisting of a capture antibody bound to microcystins/nodularin-R was used to develop the simple lateral flow immunoassay. The assay can visually detect the major hepatotoxins (microcystin-LR, -dmLR, -RR, -dmRR, -YR, -LY, -LF -LW, and nodularin-R) at and below the concentration of 4 µg/L. The signal is directly proportional to the concentration of the respective toxin, and the use of alkaline phosphatase activity offers a cost efficient alternative by eliminating the need of toxin conjugates or other labeling system. The easy to interpret assay has the potential to serve as a microcystins/nodularin screening tool for those involved in water quality monitoring such as municipal authorities, researchers, as well as general public concerned of bathing water quality.

As of 2024, approximately 81.5% of global energy consumption is still derived from non-renewable fossil fuels, such as coal, oil, and natural gas. This highlights the urgent need to transition to alternative energy sources amid the escalating climate crisis. Cyanobacteria and microalgae have emerged as promising biocatalysts in microbial fuel cells (MFCs) for eco-friendly energy production, owing to their photosynthetic abilities and resilience in regard to various environmental conditions. This review explores the potential of cyanobacteria and microalgae to drive bioelectricity generation via metabolic and extracellular electron transfer processes, leveraging their ability to fix carbon and nitrogen, while thriving in challenging environments. Bioengineering and electrode design advances are integrated to enhance the electron transfer efficacy and constancy of cyanobacteria-based MFCs. This approach addresses the growing demand for carbon-neutral energy and can be applied to wastewater treatment and bioremediation scenarios. By synergizing biological innovation with sustainable engineering techniques, this review establishes cyanobacteria and microalgal-driven MFCs as a scalable and eco-friendly platform for next-generation energy systems. The findings lay the groundwork for further exploration of the role of cyanobacteria and microalgae in bridging the gap between renewable energy production and environmental stewardship.