Application of Aggregation-Induced Emission Fluorogens for Detection and Quantification of Toxic Chemicals in Small Aquatic Organisms

The ocean is regarded as a giant dumping area for many types of toxic chemicals and the ocean ecosystem is currently under enormous stress from a variety of pollution sources. There is an urgent need to monitor biological responses and quantitatively evaluate the change of environmental health. Microalgae are vitally important to the food web in the aquatic ecosystem and can be an important indicator to monitor water pollution due to their sensitivity to chemical changes in the environment. Zooplankton is an important trophic link between primary producers and predators in an aquatic system as they are widely distributed in water and mainly consume microalgae and are subsequently are fed by fish, shrimp, and crab. Algae and zooplankton can be used to assess bioaccumulation and biomagnification of the building-up process of a chemical in living organisms along the food chain. Aggregation-induced emission (AIE) is a photophysical phenomenon where light emission of a fluorogen is activated by aggregate formation to nanoparticles, which can be used as a sensing method in biological applications for toxic chemicals. This chapter updates the recent research advance on the use of AIE as a biosensor to quantitatively detect and evaluate bioaccumulation and biorelease of mercury in algae and zooplankton in an attempt to explain the mechanism and interactions between heavy metal ions and small organisms in the aquatic ecosystem.