How I-Tech's antifouling solutions could shake up the maritime sector

Catherine Austin: With ocean temperatures rising on a global scale, marine biofouling hotspots will increase in size and severity, leaving more ships at risk of the negative impacts of biofouling on ship efficiency and fuel use. 

Ships are spending longer periods of time idle which intensifies the risk of barnacle fouling. Any organisms anchored on the hull create increased hydrodynamic drag which significantly decreases hull performance. Hard animal fouling, which includes molluscs, bryozoans, tubeworms, and barnacles cause the greatest hydrodynamic drag. 

They are also more difficult to remove once they are attached, methods for cleaning soft fouling do not work on hard fouling organisms. Barnacles secrete a cement that is among the most powerful natural glues known. 

A vessel with hard biofouling on the hull and in niche areas must burn more fuel to attain the same speed through water, resulting in higher fuel costs for the ship operator and increased emission to air. The excess friction they add to vessels’ hulls, known as ‘hard fouling’, could account for as much as 110 million tons of excess carbon emissions across the global fleet- and an additional $6 billion spent on fuel per year. 

During the Covid-19 pandemic, tens of thousands of ships sat idle at a high risk of hard fouling accumulation. That, when they set sail again would force them to burn more fuel and emit more gaseous pollutants. 

Biocidal substances are used in anti-fouling coatings to prevent biofouling. However, regulatory restrictions around biocidal control in recent years have significantly tightened the number of available biocides. 

Swedish scientists set to work on exploring alternative anti-fouling substances. Having found the target receptor (the octopamine receptor), the researchers tested how various molecules worked and affected barnacle larvae behaviour. A substance called medetomidine was used as a negative control — a molecule originally used as a sedative for large mammals. 

Instead of the expected sedating effect on the barnacle larvae, the opposite took place: they became hyperactive. The medetomidine caused an amplification in the frequency of the swimming legs kicking, forcing them to swim away from a coated surface. The brand name for the use of the medetomidine molecule and its anti-fouling properties in coatings was Selektope.

Barnacles attach to surfaces when in their cyprid larva stage but if a larva comes into contact with a coating containing Selektope, the active agent interacts with the larva’s neurological system temporarily stimulating a receptor. Once out of contact with the Selektope being leached from the coating, the effect ceases, and the larvae can swim away unharmed to settle elsewhere. 

This means that Selektope repels barnacle larvae without killing and the effect is reversible. The medetomidine molecule is also degradable over time and does not bioaccumulate in marine species. 

Selektope binds to pigment and other particles in the paint system and is therefore continuously released in the same way as other active substances and components. This contributes to long-term performance as long as the paint remains on the hull. The compatibility between Selektope and the paint matrix in the marine coatings industry, ensures as slow and steady release secures the anti-fouling effect over time.

The introduction of this technology allows shipowners to benefit from lower fuel use and costs while minimising the impact on the environment. Credit: Pixabay

Selektope is a technology characterised by its selective action and high efficacy at extremely low concentrations. This creates opportunities, that in some cases, can reduce biocide release from a paint by more than 90 percent whilst still improving hull performance. To obtain full protection against barnacle fouling, 0.1 – 0.3% w/w of Selektope should be used in a wet paint formulation. This equates to just 2 grams Selektope is used per litre of paint, comparable to 500-700 grams of copper oxide used per litre of paint for barnacle prevention. 

Global paint manufacturers can combine Selektope with several other substances and polymers in their paint formulations to create optimal fouling protection. This opens up for the possibilities of paint formulations with less biocides and therefore less leaking of biocides to the marine environment. 

Selektope also reduces the transfer of invasive species. A multitude of marine species can be carried on a fouled ship hull to new environments, where they may survive to establish a population and become invasive, out-competing native species and multiplying into pest proportions.

Around 2005-2006, there was a particularly strong focus on reducing emissions in shipping, leading to a renewed interest in advanced coatings technology. Therefore, a technology like Selektope, which could be used in tremendously small quantities and still be very selective and efficient at preventing barnacle attachment on wetted surfaces, was very desirable on paper, particularly given growing biocide restrictions were coming into effect. 

However, turning the molecule into a product was a particularly challenging process. One of the biggest challenges was the time needed to get the regulatory certifications and permissions in place. Overall, we spent six years just trying to get relevant study data to be able to do a risk assessment on the molecule, solely on the environmental side and the human exposure side. 

During the first ten years of development much of the focus was spent understanding the active substance. Large efforts were made to gain insight into the substance’s mode of action on barnacles, and at which concentrations the substance was most efficient at causing effect. The leaching behaviour of paint and possible environmental risks of using Selektope commercially was also examined in great depth. 

I-Tech was lucky to have patient and strong owners supporting the company through the European regulatory process. That, in combination with an existing toxicology data package from the substance approval as a pharmaceutical substance, made a large difference to the financial burden taken on by I-Tech.  Also, the fact that the process was approached from a very optimistic standpoint, both regarding costs, time and outcome certainly helped. 

All substances which control organisms in a non-physical manner are considered to be biocides. Selektope´s mode of action is receptor activation. Therefore, even though it is having a non- fatal effect on the affected organism, from a regulatory perspective it is a biocide. A strategic decision was made by I-Tech to achieve regulatory approval of Selektope under the implemented biocides legislation in EU – the Biocidal Products Directive 98/8/EC. 

The requirements for an application dossier under the BPD were extensive and these requirements have not lessened with time. Credible information generated by independent research organisations is required to determine an active substance’s identity and impurity profile, the physical- and chemical properties, suitable analytical methods in different matrices, toxicological- and ecotoxicological profile and its environmental fate. 

The BPR was put in place to regulate the use of biocides and avoid the situation of any substances which could pose a risk for humans or the environment being placed on the market. However, at the same time, these stringent requirements could be blocking new biocides from reaching the market. Also, the cost to develop a dossier for EU approval application containing all required information is in the range of 5-10 million euros in investment. 

Since gaining approval for a new biocide requires five batches of the substance, produced via industrial scale manufacturing, to be made available, the presence of commercial products for use in markets outside the EU can also be a way to utilise material that most likely has cost a substantial amount of money to produce.