Compounds from Silicones Alter Enzyme Activity in Curing Barnacle Glue and Model Enzymes

Background: Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity. Methodology/Principal Findings: GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents. Conclusions/Significance: Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties

Sugary interfaces mitigate contact damage where stiff meets soft

The byssal threads of the fan shell Atrina pectinata are non-living functional materials intimately associated with living tissue, which provide an intriguing paradigm of bionic interface for robust load-bearing device. An interfacial load-bearing protein (A. pectinata foot protein-1, apfp-1) with L-3,4-dihydroxyphenylalanine (DOPA)-containing and mannose-binding domains has been characterized from Atrina's foot. apfp-1 was localized at the interface between stiff byssus and the soft tissue by immunochemical staining and confocal Raman imaging, implying that apfp-1 is an interfacial linker between the byssus and soft tissue, that is, the DOPA-containing domain interacts with itself and other byssal proteins via Fe3(+)-DOPA complexes, and the mannose-binding domain interacts with the soft tissue and cell membranes. Both DOPA-and sugar-mediated bindings are reversible and robust under wet conditions. This work shows the combination of DOPA and sugar chemistry at asymmetric interfaces is unprecedented and highly relevant to bionic interface design for tissue engineering and bionic devices

Understanding Marine Mussel Adhesion

In addition to identifying the proteins that have a role in underwater adhesion by marine mussels, research efforts have focused on identifying the genes responsible for the adhesive proteins, environmental factors that may influence protein production, and strategies for producing natural adhesives similar to the native mussel adhesive proteins. The production-scale availability of recombinant mussel adhesive proteins will enable researchers to formulate adhesives that are water-impervious and ecologically safe and can bind materials ranging from glass, plastics, metals, and wood to materials, such as bone or teeth, biological organisms, and other chemicals or molecules. Unfortunately, as of yet scientists have been unable to duplicate the processes that marine mussels use to create adhesive structures. This study provides a background on adhesive proteins identified in the blue mussel, Mytilus edulis, and introduces our research interests and discusses the future for continued research related to mussel adhesion

The impact of desiccation on the adhesion of barnacles attached to non-stick coatings

Fouling-release coatings prevent fouling of ships' hulls through hydrodynamic forces generated as the ship moves through the water. The effectiveness of such coatings may be evaluated by measuring the adhesion strength of settled organisms, e.g. barnacles. The influence of desiccation of the barnacle adhesive on such measurements was investigated. Shear forces required to remove barnacles of the genus Balanus increased during the course of desiccation up to the point when the barnacles suddenly self-detached. The increase was thought to be due to the rising cohesive strength of the adhesive. Growing tensile forces within the weakly cross-linked adhesive, however, are suggested to have led to self-detachment. The shear forces required to remove barnacles of the genus Elminius were generally low and did not differ significantly during the course of desiccation. The different results may be attributed to specific base morphologies. It was concluded that measuring the adhesion strength of members of the Balanidae on non-stick surfaces in air could produce flawed results due to the influence of desiccation of the barnacle adhesive. The investigations have also provided new insights into the characteristics of barnacle adhesive

On-line and real time cell counting and viability determination for animal cell process monitoring by in situ microscopy

International audienc

On-line and real time cell counting and viability determination for animal cell process monitoring by in situ microscopy.

International audienc

In situ microscopy for on-line monitoring of CHO cell culture

International audienc