| 1. |
- Aldred, Nick, et al.
(författare)
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Confocal microscopy-based goniometry of barnacle cyprid permanent adhesive
- 2013
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Ingår i: Journal of Experimental Biology. - : Company of Biologists. - 0022-0949 .- 1477-9145. ; 216:11, s. 1969-1972
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Tidskriftsartikel (refereegranskat)abstract
- Biological adhesives are materials of particular interest in the fields of bio-inspired technology and antifouling research. The adhesive of adult barnacles has received much attention over the years; however, the permanent adhesive of the cyprid - the colonisation stage of barnacles - is a material about which very little is presently known. We applied confocal laser-scanning microscopy to the measurement of contact angles between the permanent adhesive of barnacle cyprid larvae and self-assembled monolayers of OH- and CH3-terminated thiols. Measurement of contact angles between actual bioadhesives and surfaces has never previously been achieved and the data may provide insight into the physicochemical properties and mechanism of action of these functional materials. The adhesive is a dual-phase system post-secretion, with the behaviour of the components governed separately by the surface chemistry. The findings imply that the cyprid permanent adhesion process is more complex than previously thought, necessitating broad re-evaluation of the system. Improved understanding will have significant implications for the production of barnacle-resistant coatings as well as development of bio-inspired glues for niche applications.
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| 2. |
- Aldred, Nick, et al.
(författare)
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In situ study of surface exploration by barnacle cyprids (Semibalanus balanoides) using imaging surface plasmon resonance
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Imaging surface plasmon resonance (iSPR) was employed to investigate the interfacial adhesion phenomena that occur during the exploration of immersed surfaces by barnacle cyprids (Semibalanus balanoides). It was hypothesised that since the footprint material used by cyprids for temporary adhesion has previously been related to a large cuticular glycoprotein (SIPC), the passive deposition of cyprid footprints and the binding of SIPC to surfaces might correlate. Increased surface exploration (and footprint deposition) has also been related to increased likelihood of settlement in barnacle cyprids. If a correlation between footprint deposition and SIPC binding were to exist, therefore, there would be potential for the development of a high‐throughput assay to determine the efficacy of putative antifouling chemistries against cyprids prior to, or instead of, lengthy bio‐assays. Footprints were deposited in large numbers on carboxyl‐terminated self‐assembled monolayers (SAMs) and in very small numbers on ethylene glycol‐containing SAMs and hydrogel coatings. SIPC binding also followed the same trend. An exception to the correlation was an amineterminated SAM that accumulated few cyprid footprints, but bound SIPC strongly. It is concluded that there is great potential for the iSPR technique to be used in the evaluation of putatively non‐fouling surfaces as well as improving our understanding of the nature of the cyprid footprint material and its interactions with surfaces of different chemistry. However, the use of SIPC binding as a predictor of footprint accumulation/likelihood of settlement of cyprids to surfaces would be premature at this stage without first understanding the exceptions highlighted in this study.
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| 3. |
- Aldred, Nick, et al.
(författare)
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Real-Time Quantification of Microscale Bioadhesion Events In situ Using Imaging Surface Plasmon Resonance (iSPR)
- 2011
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 3:6, s. 2085-2091
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Tidskriftsartikel (refereegranskat)abstract
- From macro- to nanoscales, adhesion phenomena are all-pervasive in nature yet remain poorly understood. In recent years, studies of biological adhesion mechanisms, terrestrial and marine, have provided inspiration for "biomimetic" adhesion strategies and important insights for the development of fouling-resistant materials. Although the focus of most contemporary bioadhesion research is on large organisms such as marine mussels, insects and geckos, adhesion events on the micro/nanoscale are critical to our understanding of important underlying mechanisms. Observing and quantifying adhesion at this scale is particularly relevant for the development of biomedical implants and in the prevention of marine biofouling. However, such characterization has so far been restricted by insufficient quantities of material for biochemical analysis and the limitations of contemporary imaging techniques. Here, we introduce a recently developed optical method that allows precise determination of adhesive deposition by microscale organisms in situ and in real time; a capability not before demonstrated. In this extended study we used the cypris larvae of barnacles and a combination of conventional and imaging surface plasmon resonance techniques to observe and quantify adhesive deposition onto a range of model surfaces (CH(3)-, COOH-, NH(3)-, and mPEG-terminated SAMs and a PEGMA/HEMA hydrogel). We then correlated this deposition to passive adsorption of a putatively adhesive protein from barnacles. In this way, we were able to rank surfaces in order of effectiveness for preventing barnacle cyprid exploration and demonstrate the importance of observing the natural process of adhesion, rather than predicting surface effects from a model system. As well as contributing fundamentally to the knowledge on the adhesion and adhesives of barnacle larvae, a potential target for future biomimetic glues, this method also provides a versatile technique for laboratory testing of fouling-resistant chemistries.
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| 4. |
- Andersson, Olof, et al.
(författare)
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Novel application of imaging surface plasmon resonance for in situ studies of the surface exploration of marine organisms
- 2009
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Ingår i: BIOINTERPHASES. - : American Vacuum Society. - 1559-4106 .- 1934-8630. ; 4:4, s. 65-68
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Tidskriftsartikel (refereegranskat)abstract
- The surface interactions of exploring cyprids of the barnacle Semibalanus balanoides were studied in situ using imaging surface plasmon resonance. It was demonstrated how the deposition of a proteinaceous adhesive could be followed in real time as the cyprids explored and temporarily attached to a surface. Furthermore, the amount of protein left on the surface when the cyprids moved on could be quantified. Clear differences were demonstrated between an oligo(ethyleneglycol) coated surface and a bare gold substrate. It is anticipated that this technique will be a valuable tool in the development of novel surface chemistries that can prevent biofouling.
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| 5. |
- Birney, Ewan, et al.
(författare)
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Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
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Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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| 6. |
- Petrone, Luigi, et al.
(författare)
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Chemistry-specific surface adsorption of the barnacle settlement-inducing protein complex
- 2015
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Ingår i: Interface Focus. - : Royal Society, The. - 2042-8898 .- 2042-8901. ; 5:1, s. 20140047-
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Tidskriftsartikel (refereegranskat)abstract
- Gregarious settlement in barnacle larvae (cyprids) is induced by a contact pheromone, the settlement-inducing protein complex (SIPC). The SIPC has been identified both in the cuticle of adult barnacles and in the temporary adhesive secretion (footprint) of cyprids. Besides acting as a settlement inducer, the presence of the SIPC in footprints points to its additional involvement in the adhesion process. SIPC adsorption behaviour was therefore investigated on a series of self-assembled monolayers (SAMs) by surface plasmon resonance at the pH of seawater (8.3). Fibrinogen and alpha(2)-macroglobulin (A2M) (blood complement protease inhibitors with which the SIPC shares 29% sequence homology) were used in the adsorption experiments as positive and negative standards, respectively. The mass uptake of the SIPC was comparable to that of fibrinogen, with adsorption observed even on the protein-resistant oligo(ethylene glycol) surface. Notably, on the positively charged SAM the SIPC showed a kinetic overshoot, indicating a metastable configuration causing the amount of adsorbed protein to temporarily exceed its equilibrium value. A2M adsorption was low or negligible on all SAMs tested, except for the positively charged surface, indicating that A2M adsorption is mainly driven by electrostatics. Evaluation of SIPC non-specific adsorption kinetics revealed that it adsorbed irreversibly and non-cooperatively on all surfaces tested.
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| 7. |
- Petrone, Luigi, et al.
(författare)
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Effects of surface charge and Gibbs surface energy on the settlement behaviour of barnacle cyprids (Balanus amphitrite)
- 2011
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Ingår i: Biofouling (Print). - : Taylor and Francis: STM, Behavioural Science and Public Health Titles / Taylor and Francis. - 0892-7014 .- 1029-2454. ; 27:9, s. 1043-1055
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Tidskriftsartikel (refereegranskat)abstract
- Gibbs surface energy has long been considered to be an important parameter in the design of fouling-resistant surfaces for marine applications. Rigorous testing of the hypothesis that settlement is related to Gibbs surface energy however has never been accomplished, due mainly to practical limitations imposed by the necessary combination of surface engineering and biological evaluation methods. In this article, the effects of surface charge and Gibbs surface energy on the settlement of cyprids of an important fouling barnacle, Balanus amphitrite, were evaluated. Settlement assays were conducted on a range of self-assembled monolayers (SAMs) (CH(3)-, OH-, COOH-, N(CH(3))(3)(+)-, NH(2)-terminated), presented in gold-coated polystyrene well plates, varying in terms of their surface charge and Gibbs surface energy. Contrary to contemporary theory, settlement was not increased by high-energy surfaces, rather the opposite was found to be the case with cyprids settling in greater numbers on a low-energy CH(3)- SAM compared to a high-energy OH- SAM. Settlement was also greater on negatively-charged SAMs, compared to neutral and positively-charged SAMs. These findings are discussed in the context of data drawn from surfaces that varied in multiple characteristics simultaneously, as have been used previously for such experiments. The finding that surface charge, rather than total surface energy, may be responsible for surface selection by cyprids, will have significant implications for the design of future fouling-resistant materials.
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