This Small Business Innovation Research Phase I project will address the market-driven need for environmentally compatible marine antifouling coating technologies that outperform the state-of-the-art. Increasing environmental regulations have led to the banning of the most effective marine antifouling coatings which rely on toxicity as their mode of action. The best performing of these coatings contain heavy metal-based organometallics which when released into the environment persist, bioaccumulate, and affect non-target species. Increasing scrutiny of any type of heavy metal antifouling approach and growing concerns related to the use of even non-metal biocides has provided a product opportunity for our toxin-free technologies premised on a mechanistically different eco-friendly antifouling strategy. Our broad objective and anticipated outcome from our green chemistry process is the creation of commercially viable, eco-friendly antifouling surface technologies for biofouling control. By integrating advanced materials and manufacturing practices with a chemical biology perspective, we plan to create low cost, durable, self-polishing, low-settlement, foul-release coatings suitable for rigorous marine applications including ship hulls and energy producing offshore structures. Our coatings will employ both non-toxic and zero-volatile organic compound (VOC) systems ushering in new generation of highly effective antifouling technologies that are environmentally more responsible than current high-VOC, metal/biocide poisoning approaches.
The broader impact/commercial potential of this project arises from a growing demand for green chemistry solutions to curtail biofouling of manmade structures. If left unchecked, the attachment and subsequent build-up of biofouling organisms, such as barnacles, will severely compromise the performance characteristics of structures such as ship hulls, aquaculture containment systems, and offshore energy-producing devices. Increased hydrodynamic drag on commercial hulls results in estimated excess fuels costs of 40 billion dollars annually and wastes natural resources and contributes to pollution. Economical antifouling technologies have the potential to disruption ecologically sensitive habitats and have shaped a product opportunity in a commercial space defined by price point, performance, and environmental regulations. Our transformative approach to developing effective, low cost, eco-friendly marine antifouling coatings evolved from a chemical biological and molecular mechanistic understanding of barnacle glue. When integrated with foul-release properties, durable coating chemistries capable of reducing settlement by preventing hardening of biofouler glue will result not only in a commercial product addressing a societal need but will also enhance our understanding of key scientific and technological principles underlying the marine biofouling problem. Participating professionals will benefit from multidisciplinary technical training in a 15 billion dollar marine coatings, ?green? collar jobs industry.
Marine biofouling is a costly nuisance impacting shipping, aquaculture, offshore drilling, and offshore tidal and wind power. Due to a high profile calcareous shell, strongly adhesive cement, and cosmopolitan distribution, barnacles are the most problematic marine hard fouling pest worldwide. Though biocidal-leaching coatings are widely employed and effective, their continued use, particularly in the context of vigorous in port hull grooming, is threatened by mounting environmental concerns driving stricter regulation of the coating industry. While the majority of antifouling coatings are designed to deter the settlement of biofouling organisms by leaching toxic substances, the best performing foul-release coatings are not without environmental toxicity concerns. Foul-release coatings are also easily damaged and expensive, and even when the coatings are new, the shear forces attained at the highest speeds appear to be insufficient to release the most troublesome hardfoulers. These challenges and limitations have created a new imperative for mechanistically different types of earth-friendly approaches for preventing biofouling that we have been seeking to address. The NSF-funded Phase I/Ib research partnership between Dr. John A. Schetz at the University of North Texas Health Science Center (UNTHSC) and Alex Walsh at ePaint Company addressed the market-driven need for environmentally compatible marine antifouling coating technologies. Increasing environmental regulations have led to the banning of the most effective marine antifouling coatings which rely on toxicity as their mode of action. The best performing of these coatings contain heavy metal-based organometallics which when released into the environment persist, bioaccumulate and affect non-target species. Increasing scrutiny of any type of intentional heavy metal leaching approach and growing concerns related to the use of even non-metal biocides has provided a product opportunity for our toxin-free technologies premised on a mechanistically different eco-friendly antifouling strategy. Specifically, our team is focused on developing eco-friendly anti-settlement polymer coatings decorated with functionalities known to inhibit enzymes important for the curing of barnacle cement. Thus our surface chemistries are designed to interfere with the functioning of barnacle glue proteins. Polymerization of novel cross-linkable monomers possessing enzyme-inhibiting surface chemistries resulted in non-toxic coatings which prevented the settlement of barnacle cyprids in laboratory and field tests. The mechanistic basis for the anti-settlement result was corroborated by comparing the interactions of a curing enzyme surrogate with the surface of polymer coatings possessing or lacking anti-curing functionalities. Consistent with our molecular mechanistic explanation, functionalized coatings with cyprid anti-settlement properties bound a model enzyme while non-functionalized coatings did not. We are currently working towards developing target-based high throughput screening technologies (HTS) to optimize our antifouling coatings analogous to HTS approaches routinely utilized in pharmaceutical drug discovery and development programs. In the course of this Phase I/Ib work, we not only developed novel eco-friendly barnacle anti-settlement coatings possessing barnacle glue anti-curing functionalities, but we also discovered a second mechanistically distinct eco-friendly antifouling coating technology which photocatalytically generates a hydrogen peroxide deterrent at the coating surface. The hydrogen peroxide rapidly decomposes to oxygen and water in the environment. The biofouling resistance of coated aquaculture netting and caging gear has been confirmed by commercial partners from the shellfish and finfish aquaculture industry. These same aquaculture companies have requested for the 2014 season more product developed in Phase I/Ib and commercialized by ePaint Company.