| AVS 54th International Symposium | |
| Marine Biofouling Topical Conference | Monday Sessions |
| Session MB+BI-MoM |
| Session: | Biological Interactions at the Marine Interface |
| Presenter: | B. Liedberg, Linköping University, Sweden |
| Authors: | B. Liedberg, Linköping University, Sweden P. Nygren, Linköping University, Sweden M. Östblom, Linköping University, Sweden Y. Zhou, Linköping University, Sweden T. Ederth, Linköping University, Sweden |
| Correspondent: | Click to Email |
Positively charged peptides have been synthesized in our laboratory with the purpose of investigating their anti-biofouling potential. The peptides contain a common leading sequence of Cys(Gly)2 where the cysteine residue offers an convenient handle for oriented attachment to gold. The functional part of the peptides (7-mers) consists of alternating ArgTyr, LysTyr, LysTyrGly as well as mixed layers of ArgTyr and a filling Cys(Gly)3 peptide. The peptide layers have been prepared from aqueous solutions and were characterized with respect to layer thickness, conformation and long-term stability in artificial seawater (ASW) using null ellipsometry and infrared spectroscopy. The peptide layers were also examined with respect to settlement of Ulva linza zoospores. The functional ArgTyr, LysTyr, LysTyrGly peptides displayed enhanced settlement as compared to reference surfaces/coatings. Moreover, the settlement on the ArgTyr layer was greatly increased as compared to the other peptide layers, and the amount of settled spores increased with increasing fraction of the ArgTyr. Most importanty, however, the Ulva spores seemed to settle in a side-on conformation on the ArgTyr layer with their flagella (swimming arms) intact. This mode of settlement has not been observed before. Pre-incubation of the Ulva spores in a solution containing the ArgTyr peptide also influenced the subsequent attachment of the spores to polystyrene in a concentration dependent manner. The ArgTyr peptides in solution seemed to stimulate the settlement up to a concentration of ca. 20 μM above which the number of settled spores started to fall. Microscopic examination of the remaining spore solution after settlement suggests that this is due to an increase in spore death. Thus, the Arg residues in the ArgTyr peptide are believed to convey a membrane-associating effect which seems to have a deterring effect upon settling organisms. Complementary experiments on diatoms (a cell surrounded by a silica shell) revealed that these species settle in a non-selective manner on the different peptides. In addition, ongoing experiments using QCM to study vesicle adsorption onto the peptide layers give support to the suggested peptide-membrane association meachanism that resulted in an abnormal, side-on, attachment of Ulva spores. Interestingly, recent preliminary experiments using barnacle cyprids revealed marginal settlement on the ArgTyr peptide layer.