Antimacrofouling Efficacy of Innovative Inorganic Nanomaterials Loaded with Booster Biocides

Abstract

Abstract:The application of nano-structured compounds has been increasing rapidly in recent years, in several fields. The use of engineered nano-materials as carriers of antifouling compounds is just beginning and already reveals clear advantages compared to bulk active compounds, such as slowed and controlled release, novel functionality, and high loading capacity. This present study assesses the antifouling efficacy of two nanostructured materials, spherical mesoporous silica nanocapsules (SiNC) and Zn-Al layered double hydroxides (LDH), loaded with two commercial biocides, zinc prithione (ZnPT) and copper pyrithione (CuPT). The study used adult mussels from three geographical regions, the Atlantic Ocean, Mediterranean Sea, and the Red Sea, to examine the efficacy of the innovative compounds. The efficacy of these compounds on larvae of the bryozoan Bugula neritina from the Mediterranean Sea and the Red Sea was also examined. The results of this study demonstrated the environmentally friendly properties of unloaded LDH against the two-model systems, adult mussels or bryozoan larvae. ZnPT entrapped in LDH demonstrated the most effective antifouling compound against the two model systems. A comparison of the impact of the two compounds on macrofouling organisms from the different marine habitats examined in this study indicates a distinction associated with the organisms' different ecosystems. The Red Sea mussels and bryozoans, representing a tropical marine ecosystem, yielded the highest efficacy values among tested Atlantic Ocean and Mediterranean Sea mussels and bryozoans.

Can Encapsulation of the Biocide DCOIT Affect the Anti-Fouling Efficacy and Toxicity on Tropical Bivalves?

“…This can be justified by the very low and slow release of DCOIT from the nanocapsules through diffusion, during the exposure period (undetectable by HPLC with a high detection limit of 240 µg DCOIT L −1 [12]). Interestingly, similar findings were previously reported on settlement inhibition assays of other foulers, such as the bryozoan Bugula neritina, and the mussels Mytilus galloprovincialis and Brachidontes pharaonis, in a study comparing the efficacy of other AF nanomaterials containing Zn or Cu pyrithiones (ZnPT and CuPT) and the respective free/dissolved forms [33]. As an example, CuPT immobilized in engineered nanoclays (LDH) can be up to 250-fold more efficient in inhibiting the settlement of the Mediterranean B. neritina larvae than CuPT [33].…”

“…Interestingly, similar findings were previously reported on settlement inhibition assays of other foulers, such as the bryozoan Bugula neritina, and the mussels Mytilus galloprovincialis and Brachidontes pharaonis, in a study comparing the efficacy of other AF nanomaterials containing Zn or Cu pyrithiones (ZnPT and CuPT) and the respective free/dissolved forms [33]. As an example, CuPT immobilized in engineered nanoclays (LDH) can be up to 250-fold more efficient in inhibiting the settlement of the Mediterranean B. neritina larvae than CuPT [33]. Naturally, species sensitivity may differ across the worldwide marine ecosystems, and abiotic factors, such as temperature and salinity can affect the performance of AF compounds [33].…”

“…CTAB is a quaternary ammonium compound (QACs), a class of toxic surfactants towards aquatic species [12,31]. Besides, residues of this organic component can be detected even after several washes [12] explaining the recently reported effects of SiNC on the fertilization and embryo-larval development of the sea-urchin Paracentrotus lividus [32] and the inhibition settlement of the bryozoan Bugula neritina larvae [33]. This raw nanomaterial is not considered environmentally dangerous when compared with the AF biocides, but our results indicate the importance of knowing its potential toxicity against a wide set of organisms in order to improve the manufacturing process of the engineered nanomaterial, as recently proposed by Kaczerewska et al [34].…”

“…As an example, CuPT immobilized in engineered nanoclays (LDH) can be up to 250-fold more efficient in inhibiting the settlement of the Mediterranean B. neritina larvae than CuPT [33]. Naturally, species sensitivity may differ across the worldwide marine ecosystems, and abiotic factors, such as temperature and salinity can affect the performance of AF compounds [33]. Despite more studies are needed with other fouler organisms, it is safe to conclude that the innovative nanomaterials demonstrate a promising antifouling capacity.…”

Smart Nanocontainers: Preparation, Loading/Release Processes and Applications

“…Several biocides have been loaded into the nanocontainers, such as zinc pyrithione and copper pyrithione [98], benzalkonium chloride [99], mercaptobenzothiazole and 4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) [100], commercial antifouling compounds [101].…”