Settlement and adhesion of algal cells to hexa(ethylene glycol)-containing self-assembled monolayers with systematically changed wetting properties

Abstract

Protein resistance of self-assembled monolayers (SAMs) of hexa(ethylene glycols) (EG(6)) has previously been shown to be dependent on the alkoxyl end-group termination of the SAM, which determines wettability [S. Herrwerth, W. Eck, S. Reinhardt, and M. Grunze, J. Am. Chem. Soc. 125, 9359 (2003)]. In the present study, the same series of hexa(ethylene glycols) was used to examine the correlation between protein resistance and the settlement and adhesion of eukaryotic algal cells, viz., zoospores of the macroalga Ulva and cells of the diatom Navicula, which adhere to the substratum through the secretion of protein-containing glues. Results showed that the initial settlement of Ulva zoospores was highest on the hydrophilic EG(6)OH but that cells were only weakly adhered. The number of Ulva zoospores and Navicula cells firmly adhered to the SAMs systematically increased with decreasing wettability, as shown for the protein fibrinogen. The data are discussed in terms of hydration forces and surface charges in the SAMs.

Surface Sensing and Settlement Strategies of Marine Biofouling Organisms

“…Such inert coatings have been identified for a number of well-defined surfaces in short term, single species assays. Especially ethylene glycol (EG) x -containing coatings have been used in the biomedical area [21][22][23][24] and have recently been investigated with respect to their marine anti-fouling potential [25][26][27][28][29][30][31][32][33]. However, the degradation of the ethylene-glycol-containing chemistries makes them unsuitable for long-term antifouling applications [34,35].…”

“…The Callow group established an assay that allows spores to settle within 45 min to surfaces in order to compare the spore accumulation rate on different surfaces and thus to discriminate their non-fouling potential [62]. A vast number of experiments demonstrated that the settlement kinetics of zoospores of Ulva is affected by a number of physical and chemical surface cues, such as wettability [31,64,67,68], topography [69][70][71][72], and charge [73,74]. Especially self-assembled monolayers (SAM) [75,76] are a versatile class of functional interfaces that are frequently applied in biofouling research, since their mechanical properties are determined by the substrate and thus biological response is solely caused by the surface chemistry.…”

“…Extensive studies followed, focusing on various surface properties including wettability, hydration, and lubricity [31,33,64,67,77,78]. Figure 6a shows a compiled viewgraph of Ulva linza zoospore settlement, Navicula perminuta settlement, and protein resistance on different aliphatic SAMs [64], methyl terminated oligosaccharide SAMs [48,65], and oligoethyleneglycol based SAMs with aliphatic termination [31]. The individual data sets have been rescaled so that they can directly be compared.…”

“…6 The effect of wettability on spore and algae accumulation. a Compiled data for accumulation of algae (Ulva: filled circles; Navicula: diamonds) and proteins (crosses) on three chemically different SAMs: Ulva settlement on mixed hydroxyl and methyl terminated alkylthiols (green, data kindly provided by M. Callow) [64], Ulva and Navicula settlement and protein adsorption on hexaoligoethylene glycol SAMs with different aliphatic termination (red, Schilp et al [31].) and protein adsorption and Ulva settlement on oligosaccharides with different degrees of methylation (blue, Hederos et al [48,65], data kindly provided by B. Liedberg).…”

Settlement Behavior of Zoospores of Ulva linza During Surface Selection Studied by Digital Holographic Microscopy

“…Settlement of zoospores of U. linza is 'selective', i.e., the spores respond to physical and chemical surface cues such as wettability [4][5][6][7], topography [8][9][10][11], and charge [12,13], resulting in clear settlement preferences and therefore variable surface colonization by the alga. The question arises as to how spores exert this selectivity-for example; does it involve different behavioral responses in terms of swimming patterns, trajectories and velocities?…”