Bioinspired Serotonin Antagonists as Universal Antifouling Agents against Complex Marine Biofouling

Marine fouling is a burden to the environment and economy. The diversity of marine fouling organisms has led to the development of poisonous antifouling agents. Nevertheless, toxic antifouling agents pose ecological challenges because they accumulate in the food chain; consequently, a new environmentally sustainable solution that is nontoxic to marine organisms yet universally effective against complex biofouling species is needed. Here, we replace persistent biocides with transient antagonists as key antifouling materials, with serotonin-receptor antagonists used to control marine fouling because mussels and barnacles rely on the serotonin receptor to sense surfaces. Chlorpromazine exhibits the best antifouling capability among the antagonists tested, preventing fouling by hard fouling organisms, such as mussels and barnacles, and by soft fouling organisms, such as algae, exemplified by the series of antifouling-coating efficacy trials, including a 12-week dynamic oceanic ship test and an 18-week static ocean environment test. Serotonin receptor antagonists inhibit the formation of biofilms (microfouling), thereby suppressing underlying mechanisms that lead to macrofouling. The antagonists are metabolized and excreted rather than accumulating in organisms; an antagonist-based antifouling strategy is a sustainable approach for controlling marine fouling for both static and dynamic ocean environments.