Recent approaches in designing bioadhesive materials inspired by mussel adhesive protein

Marine mussels secret protein-based adhesives, which enable them to anchor to various surfaces in a saline, intertidal zone. Mussel foot proteins (Mfps) contain a large abundance of a unique, catecholic amino acid, Dopa, in their protein sequences. Catechol offers robust and durable adhe-sion to various substrate surfaces and contributes to the curing of the adhesive plaques. In this article, we review the unique features and the key functionalities of Mfps, catechol chemistry, and strategies for preparing catechol-functionalized poly- mers. Specifically, we reviewed recent findings on the contributions of various features of Mfps on interfacial binding, which include coacervate formation, surface drying properties, control of the oxidation state of catechol, among other features. We also summarized recent developments in designing advanced biomimetic materials including coacervate-forming adhesives, mechanically improved nano- and micro-composite adhesive hydrogels, as well as smart and self-healing materials. Finally, we review the applications of catechol-functionalized materials for the use as biomedical adhesives, therapeutic applications, and antifouling coatings

Adhesives and coatings inspired by mussel adhesive proteins

Mollusks such as the blue mussel (Mytilus edulis) secrete adhesive proteins that exhibit strong and reliable underwater adhesions. A key adhesive component in these adhesive proteins is an amino acis, 3,4-dihydroxyphenylalanene (DOPA), which is responsible for both interfacial binding and intermolecular cross-linking. DOPA is a unique and versatile adhesive moiety, capable of binding to both inorganic and organic surfaces through either strong reversible bonds or covalent attachment. This chapter reviews the chemistry of DOPA side chain and the use of DOPA and its derivatives (e.g., dopamine) as building blocks in developing mussel-inspired adhezives, coatings, and multifunctional polymeric anchors for various applications

Inundation and precipitation effects on growth and flowering of the high marsh species Juncus gerardii

© 2014. Accelerated sea level rise threatens coastal wetland plant communities where coastal development restricts transgression, and inundation increases and declining sediment supplies limit the capacity of coastal wetlands to build in elevation. Juncus gerardii Loisel., black needle rush, is a high latitude cosmopolitan plant species and, within salt marshes of the U.S. mid-Atlantic and New England coasts, it occupies a narrow belt along the marsh-upland border. Examination of historic aerial photography, vegetation resurveys, and peat composition analysis for U.S. Northeastern marshes have shown vegetation change patterns indicative of increased inundation, including decline of J. gerardii. To interpret loss patterns for J. gerardii in southern New England, we conducted a factorial experiment to establish its sensitivity to inundation and drought. A strong relationship was found between inundation and growth for J. gerardii, which together with marsh elevation and water level data, suggests that growth is reduced by current flooding patterns. Examination of J. gerardii flowering also indicates that floret and inflorescence density vary with inundation, suggesting that negative impacts of sea level rise on Juncus may extend to seed production. Late spring and summer drought impacted neither J. gerardii growth nor its flowering, implying that J. gerardii is insensitive to below-average precipitation or drought during this time of year. We conclude that current inundation patterns are incompatible with robust growth for J. gerardii, and recommend conservation actions be focused on the marsh-upland border to facilitate the upslope migration of J. gerardii and other transitional high marsh plant species

Preventing adhesion on medical devices

(undefined

Anisotropic Foams Via Frontal Polymerization

The properties of foams, an important class of cellular solids, are most sensitive to the volume fraction and openness of its elementary compartments; size, shape, orientation, and the interconnectedness of the cells are other important design attributes. Control of these morphological traits would allow the tailored fabrication of useful materials including highly porous solids, anisotropic heat conductors, tough composites, among others. While approaches like ice templating has produced foams with elongated cells, there is a need for rapid, versatile, and energy efficient methods that also control the local order and macroscopic alignment of cellular elements. Here we describe a fast and convenient method to obtain anisotropic structural foams using frontal polymerization. We fabricated foams by curing mixtures of dicyclopentadiene and a physical blowing agent via frontal ring opening metathesis polymerization (FROMP). The materials were characterized using micro-computed tomography and an image analysis protocol to quantify morphological characteristics including volume fraction and anisotropy. The cellular structure, porosity, and hardness of the foams changed with blowing agent, concentration, and resin viscosity. Moreover, we used a full factorial combination of variables to correlate each parameter with the structure of the obtained foams. We found a strong correlation between the resin viscosity and the foam’s cellular structure. Furthermore, a specific combination of input parameters controlled the transitions from (i) isotropic to anisotropic cellular structures, (ii) porous to non-porous, and (iii) soft to hard foams. Our results demonstrate the controlled production of foams with specific morphologies using the simple and efficient method of frontal polymerization. This work shows promise for creating foams with aligned cellular structures that allow anisotropic mass and energy transport properties in high performance structural solids

Sea level rise, drought and the decline of Spartina patens in New England marshes

© 2016 Elsevier Ltd. Already heavily impacted by coastal development, estuarine vegetated habitats (seagrasses, salt marshes, and mangroves) are increasingly affected by climate change via accelerated sea level rise, changes in the frequency and intensity of precipitation and storms, and warmer ocean temperatures. Conservation of these sensitive and vulnerable habitats requires the recognition of climate change effects so environmental managers can develop and apply appropriate intervention and adaptation strategies where possible. Here we focus on Spartina patens (saltmeadow cordgrass), a foundation species of New England (USA) coastal marshes. A growing body of evidence suggests this species is disappearing rapidly from wetlands in the region, leading to reductions in habitat quality, plant diversity, carbon sequestration, erosion resistance and coastal protection. We grew S. patens under five inundation and three precipitation regimes, monitored changes in its extent within two Southern New England coastal marshes (2000-2014), and used water level and precipitation data to detect changes in environmental conditions affecting these marshes. Our results suggest that current inundation patterns have reduced the persistence of S. patens, while short-term drought did not appear responsible for vegetation changes or habitat conversion. We conclude that accelerated sea level rise is incompatible with the long-term survival of S. patens within the current landscape footprint of Southern New England\u27s coastal wetlands. We suggest that conservation actions focused on high marsh preservation concentrate on facilitating the process of marsh migration onto uplands by prioritizing buffer conservation, conducting barrier removal and allowing for retreat where feasible

Growth and photosynthesis responses of two co-occurring marsh grasses to inundation and varied nutrients

© 2015, National Research Council of Canada. All Rights Reserved. For tidal marshes of the US Northeast, the late twentieth century decline of Spartina patens(Aiton) Muhl. has been attributed to increased flooding associated with accelerated sea level rise and nitrogen over-enrichment from cultural eutrophication. The objective of this study was to examine the impacts of inundation and nutrient availability on growth, photosynthesis, and interactions of S. patens and Distichlis spicata (L.) Greene, which co-occur and are common marsh species. Plants were grown in a factorial greenhouse experiment, where flow-through seawater was used to simulate semidiurnal tides. Field surveys were additionally conducted to relate plant distributions to environmental conditions. For S. patens grown in monoculture, nutrient additions did not enhance growth for the high inundation treatment. In addition, the combination of high nutrient availability and high inundation adversely affected S. patens tiller density, photosynthetic efficiency, and leaf CO2 uptake. For D. spicata, nutrient additions enhanced growth for both inundation treatments with respect to aboveground biomass and tiller density. For species pairings, S. patens expanded relative to D. spicata under low inundation, low nutrient availability conditions, but declined relative to D. spicata under daily inundation in combination with nutrient amendments. These findings were additionally supported by field data, which indicated that D. spicata was more common than S. patens where nutrient availability was high. These results suggest that S. patens persistence is favored by low nutrient inputs and well-drained conditions, and supports the interpretation that this species is vulnerable to loss where high nutrient loads coincide with accelerated sea level rise

Probing Electrolyte Influence on CO₂ Reduction in Aprotic Solvents

Selective CO2 capture and electrochemical conversion are important tools in the fight against climate change. Industrially, CO2 is captured using a variety of aprotic solvents due to their high CO2 solubility. However, most research efforts on electrochemical CO2 conversion use aqueous media and are plagued by competing hydrogen evolution reaction (HER) from water breakdown. Fortunately, aprotic solvents can circumvent HER, making it important to develop strategies that enable integrated CO2 capture and conversion. However, the influence of ion solvation and solvent selection within nonaqueous electrolytes for efficient and selective CO2 reduction is unclear. In this work, we show that the bulk solvation behavior within the nonaqueous electrolyte can control the CO2 reduction reaction and product distribution occurring at the catalyst–electrolyte interface. We study different tetrabutylammonium (TBA) salts in two electrolyte systems with glyme ethers (e.g., 1,2 dimethoxyethane or DME) and dimethyl sulfoxide (DMSO) as a low and high dielectric constant medium, respectively. Using spectroscopic tools, we quantify the fraction of ion pairs that forms within the electrolyte. Also, we show how ion pair formation is prevalent in DME and is dependent on the anion type. More importantly, we show that as ion pair formation decreases within the electrolyte, CO2 current densities increase, and a higher CO Faradaic efficiency is observed at low overpotentials. Meanwhile, in an electrolyte medium where the ion pair fraction does not change with the anion type (such as in DMSO), a smaller influence of solvation is observed on CO2 current densities and product distribution. By directly coupling bulk solvation to interfacial reactions and product distribution, we showcase the importance and utility of controlling the reaction microenvironment in tuning the electrocatalytic reaction pathways. Insights gained from this work will enable novel electrolyte designs for efficient and selective CO2 conversion to desired fuels and chemicals

Extending BigSMILES to non-covalent bonds in supramolecular polymer assemblies

Non-covalent BigSMILES enables the representation of donor/acceptor interactions and delocalized bonds for polymer assemblies.</jats:p