Nanocoating Is a New Way for Biofouling Prevention

Biofouling is a major concern to the maritime industry. Biofouling increases fuel consumption, accelerates corrosion, clogs membranes and pipes, and reduces the buoyancy of marine installations, such as ships, platforms, and nets. While traditionally marine installations are protected by toxic biocidal coatings, due to recent environmental concerns and legislation, novel nanomaterial-based anti-fouling coatings are being developed. Hybrid nanocomposites of organic-inorganic materials give a possibility to combine the characteristics of both groups of material generating opportunities to prevent biofouling. The development of bio-inspired surface designs, progress in polymer science and advances in nanotechnology is significantly contributing to the development of eco-friendly marine coatings containing photocatalytic nanomaterials. The review mainly discusses photocatalysis, antifouling activity, and formulation of coatings using metal and metal oxide nanomaterials (nanoparticles, nanowires, nanorods). Additionally, applications of nanocomposite coatings for inhibition of micro- and macro-fouling in marine environments are reviewed.

Antibacterial Properties of Glycosylated Surfaces: Variation of the Glucosidal Moiety and Fatty Acid Conformation of Grafted Microbial Glycolipids

<div>Glycosylated surfaces can display antimicrobial properties. It has been shown that sophorolipids can be used to develop biocidal coatings against Gram-positive and Gramnegative bacteria, but with a limited efficiency so far. Therefore, it appears necessary to further investigate the surface antibacterial activity of a broader set of structurally related glycolipids.</div><div>The present work explores the influence of the glucosidic moiety (gluco-, sophoro-, cellobio-)</div><div>and the fatty acid backbone (saturated, cis or trans monounsaturated). We show that the fatty</div><div>acid backbone plays an important role: cis derivative of sophorolipids (SL) grafted onto model</div><div>gold surfaces has better biocidal properties than saturated (SL0) and trans monounsaturated</div><div>(SLt) molecules, which appear to be inefficient. The number of glucose units is also a key factor:</div><div>a one-third decrease in antibacterial activity is observed when having one glucose unit (GL)</div><div>compared to two (SL).Sugar acetylation (SLa) does not seem to have an impact on the biocidal</div><div>properties of surfaces. These results are not limited to sophorolipids, cellobioselipids (CL)</div><div>leading to similar antibacterial observations. </div>

Antibacterial Properties of Glycosylated Surfaces: Variation of the Glucosidal Moiety and Fatty Acid Conformation of Grafted Microbial Glycolipids

<div>Glycosylated surfaces can display antimicrobial properties. It has been shown that sophorolipids can be used to develop biocidal coatings against Gram-positive and Gramnegative bacteria, but with a limited efficiency so far. Therefore, it appears necessary to further investigate the surface antibacterial activity of a broader set of structurally related glycolipids.</div><div>The present work explores the influence of the glucosidic moiety (gluco-, sophoro-, cellobio-)</div><div>and the fatty acid backbone (saturated, cis or trans monounsaturated). We show that the fatty</div><div>acid backbone plays an important role: cis derivative of sophorolipids (SL) grafted onto model</div><div>gold surfaces has better biocidal properties than saturated (SL0) and trans monounsaturated</div><div>(SLt) molecules, which appear to be inefficient. The number of glucose units is also a key factor:</div><div>a one-third decrease in antibacterial activity is observed when having one glucose unit (GL)</div><div>compared to two (SL).Sugar acetylation (SLa) does not seem to have an impact on the biocidal</div><div>properties of surfaces. These results are not limited to sophorolipids, cellobioselipids (CL)</div><div>leading to similar antibacterial observations. </div>

Antibacterial Properties of Glycosylated Surfaces: Variation of the Glucosidal Moiety and Fatty Acid Conformation of Grafted Microbial Glycolipids

<div>Glycosylated surfaces can display antimicrobial properties. It has been shown that sophorolipids can be used to develop biocidal coatings against Gram-positive and Gramnegative bacteria, but with a limited efficiency so far. Therefore, it appears necessary to further investigate the surface antibacterial activity of a broader set of structurally related glycolipids.</div><div>The present work explores the influence of the glucosidic moiety (gluco-, sophoro-, cellobio-)</div><div>and the fatty acid backbone (saturated, cis or trans monounsaturated). We show that the fatty</div><div>acid backbone plays an important role: cis derivative of sophorolipids (SL) grafted onto model</div><div>gold surfaces has better biocidal properties than saturated (SL0) and trans monounsaturated</div><div>(SLt) molecules, which appear to be inefficient. The number of glucose units is also a key factor:</div><div>a one-third decrease in antibacterial activity is observed when having one glucose unit (GL)</div><div>compared to two (SL).Sugar acetylation (SLa) does not seem to have an impact on the biocidal</div><div>properties of surfaces. These results are not limited to sophorolipids, cellobioselipids (CL)</div><div>leading to similar antibacterial observations. </div>

Modern approaches for the development of marine antifouling coatings

At present, 75–80% of the current operating costs of conventional transport are expended for fuel. According to the International Maritime Organization the world fleet burns 300 million tons of fuel annually, releasing into the atmosphere 960 million tons of СО2and 9 million tons of SO2. By 2020, without new technologies that reduce fuel consumption, air emissions can grow 40%, taking into account constantly increasing volumes of traffic. Therefore, defense methods against marine overgrowth are an urgent topic, and many leading firms are developing antifouling solutions. The paper considers the main means of protection against fouling with the help of polymer coatings, namely: contact active coatings; non-leaching coatings; self-polishing coatings; non-biocidal coatings. The mechanism of using polymer coatings, as well as their advantages and disadvantages, is described.