This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers at Sultan Qaboos University have developed engineered surfaces that combine microscopic patterns with zinc oxide nanorods to reduce the attachment of bacteria and microalgae—a process that contributes to biofouling on submerged marine and industrial equipment. Biofouling occurs when microorganisms and larger marine organisms accumulate on surfaces exposed to water.
It can reduce vessel performance, increase fuel consumption, accelerate corrosion, block water intakes and heat exchangers, and affect aquaculture equipment. These challenges have driven efforts to develop durable antifouling materials with reduced environmental toxicity. In the new study, researchers fabricated zinc oxide nanorod coatings on three differently patterned polymer surfaces, identified as D1, D2 and D3.
The resulting materials combined microscale surface patterns with nanoscale zinc oxide structures. The work is published in the journal PLOS One. The team tested the engineered surfaces under laboratory flow conditions using the bacterium Escherichia coli and the marine diatom Amphora sp.
They also assessed possible acute toxicity using larvae of the whiteleg shrimp Litopenaeus vannamei. The zinc oxide coatings made the patterned surfaces highly water-repellent, with water contact angles of approximately 150–165 degrees, compared with around 80–90 degrees for the uncoated surfaces. The results showed that the coatings reduced bacterial attachment by 60.3%, 48.8% and 5.8% on the D1, D2 and D3 surfaces, respectively.
Diatom coverage was reduced by 9.9%, 72.9% and 71.8% on the corresponding coated surfaces. The researchers attributed the antifouling effects to a combination of factors, including the release of zinc ions, the generation of reactive oxygen species, surface wettability and the interaction between the micro- and nanoscale structures. Toxicity varied depending on the surface design.
The zinc oxide-coated D1 surface showed the best overall balance between antifouling performance and low toxicity toward shrimp larvae. In contrast, the coated D3 surface demonstrated lower antibacterial performance and greater larval toxicity, highlighting the importance of carefully designing the underlying surface pattern rather than relying on the coating material alone. Microscopic examination after the biological experiments showed that the zinc oxide nanorods remained structurally intact, indicating that the coatings were stable during the laboratory testing period.
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