Antimacrofouling Efficacy of Innovative Inorganic Nanomaterials Loaded with Booster Biocides

Eldad Gutner-Hoch,Tania Teixeira,Michal Weis,Chen Piller,Yehuda Benayahu,João Tedim,Iris Preiss,Amadeu Soares,Roberto Martins,Susana Loureiro,Frederico Maia,Tania Oliveira,Severine Larroze

doi:10.3390/jmse6010006

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.

Highlights

Biofouling is a natural process that relates to the gradual adhesion, accumulation, and growth of a variety of organisms on submerged surfaces [1,2]
Smallmatek (Aveiro, Portugal) developed and produced both the unloaded nanostructured materials (spherical mesoporous silica nanocapsules (SiNC) and Zn-Al layered double hydroxides (LDH)) and the four loaded engineered nanomaterials, corresponding to both biocides individually immobilized/encapsulated in the above nanomaterials (i.e., layered doubled hydroxides (LDH)-zinc pyrithione (ZnPT), LDH-CuPT, SiNC-ZnPT and SiNC-CuPT)
The empty carriers LDH and SiNC yielded the lowest efficacy during the EC50 assays on mussels: LDH with EC50 of 35.7, 15.6, and 106.3 mg/L for Atlantic coast (ATL), MED, and Red Sea (RED), respectively, and SiNC with EC50 of 11.8 and 20.9 mg/L for MED and RED, respectively (Figure 1, Table 2)

Summary

Introduction

Biofouling is a natural process that relates to the gradual adhesion, accumulation, and growth of a variety of organisms on submerged surfaces [1,2]. The colonization of such surfaces begins with the conditioning of the substratum by dissolved organic compounds derived from the ambient seawater [3]. The antifouling active elements are diverse and range from the widely used metallic antifoulants and organic booster biocides [7], surface-structured compounds [8], protein adsorption inhibitors [9], quorum sensing inhibitors [10], and natural biocides [11], to microorganisms with antifouling properties [12]. The coating formulation enables maximizing the performance of the antifouling paint

Objectives

Methods

Results

Conclusion