Browsing by Subject "Antifouling"

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Open Access
Learning to glue underwater: Inspiration from the decorator worm
(2016-04-28) Diana, Zoie
The decorator worm, a sedentary predator, builds a micro-reef on the portion of its tube above the sediment, which attracts prey. When tube tops are clipped in the lab, the worm rebuilds compulsively. Glass beads and antifouling materials were used as decoration substrates to characterize bioadhesive biochemistry and adhesion to antifouling substrate. Decorator worm adhesive was largely proteinaceous with phosphate presence and a lack of glycoprotein. The Introduction explains the scientific context for studying natural underwater adhesives, including efforts to understand conserved molecular mechanisms in underwater adhesion to further fouling prevention on boat hulls or medical implants and biomimicking natural glues for industrial or biomedical applications. The Methods provides detailed steps to test decorator worm adhesive for protein, phosphoprotein, and glycoprotein presence. This section also provides details on how to make worms decorate with antifouling substrates. The Results section shows that decorator worm bioadhesive is highly proteinaceous and has higher phosphate presence in the tube as compared to glue on glass beads. The adhesive did not contain significant glycoprotein. The decorator worm adheres mixed ion exchange resin, synthetic ion exchange resin, strongly basic anion exchange resin, aminopropyl silane modified glass particles (.5-10 μm), imitation seagrass, plastic zip ties, iPhone cases, silicone, silicone infused with octamethylcyclotetrasiloxane (D4) and silicone infused with decamethylcyclopentasiloxane (D5) to its tube. This report details findings on the decorator worm as a novel system for studying adhesive and antifouling materials: • Adhesive shows high protein content • Tube adhesive shows higher phosphoprotein than adhesive on glass beads • Adhesive shows little to no glycoprotein presence • Decorator worms adheres all materials tested to their tubes • Decorator worms relatively large size and readiness to adhere any material to the exterior tubes make them excellent candidates to testing antifoul release materials
Open Access
Synthesis and Grafting To of Biomimetic Bottlebrush Polymers
(2020) Navarro, Luis Alexander
Specifically-adsorbed bottlebrush coatings are found in nature as brush-like glycoproteins that decorate biointerfaces and provide anti-fouling, lubrication, or wear-protection. These molecules contain a surface-adhesive headgroup to anchor macromolecules to a target surface and a bottlebrush polymer that endows the surface with a beneficial property, like antifouling. These glycoproteins can be effectively mimicked using protein-bottlebrush hybrids, but many challenges still exist to robustly produce such polymers. Furthermore, the use of glycoprotein-like bottlebrush coatings is limited by the current lack of understanding of their adsorption behavior and surface conformation. In this work, I first develop a modular synthesis to facilitate the production of protein-brush hybrids. I successfully made a range of protein-brush hybrids baring elastin-like polypeptides (ELP) as model proteins by using copper-catalyzed azide-alkyne cycloaddition and newly discovered diazotransfer reagents. I demonstrated the effectiveness of this synthetic path at each step through careful characterization with 1H-NMR, FTIR, GPC, and diagnostic test reactions on SDS-PAGE. In the second half of this work, I determine the relationships between the dimensions of end-adsorbing bottlebrush polymers and their adsorption behavior. Specifically, I examine the adsorption behavior of PEG-based, biotinylated bottlebrushes with different backbone and bristle lengths to streptavidin model surfaces in PBS. By using QCM, LSPR, and AFM, I learned how bottlebrush dimensions impact their adsorption kinetics, surface conformation, mechanical properties, and anti-fouling properties. Our bottlebrushes qualitatively mirror the adsorption behavior of linear polymers and exhibit three kinetic regimes of adsorption: (I) a transport-limited regime, (II) a pause, and (III) a penetration-limited regime. Furthermore, bristle length more dramatically affects brush properties than backbone length. Generally, larger bottlebrush dimensions lead to reduced molar adsorption, retarded kinetics, weaker anti-fouling, and softer brush coatings. Longer bristles also lead to less mass adsorption, while the opposite trend is observed for increasing backbone length. In summary, these findings aid the rational design of new bottlebrush coatings by elucidating how their dimensions impact adsorption, surface conformation, and the properties of the final coating.