A novel geometry for a laboratory-based larval settlement assay

Abstract

A novel configuration, consisting of two apposing surfaces bounding a vertical water column, is presented and evaluated for settlement assays using cyprids of Balanus amphitrite. Assays were conducted on planar surfaces, ranging from hydrophobic polystyrene to hydrophilic glass and including CH(3)- and NH(3) (+)-terminated self-assembled monolayers (SAMs). Identical apposing surfaces generated settlement rates comparable to those obtained in prior studies, while a choice assay yielded consistent results, with individual replicates each indicating the preferred surface for settlement. As gravity favours contact with the lower apposing surface, cyprids trapped at the air/water interface settled on or around the perimeter where the water column meets the lower substratum. These cyprids are capable of selecting a settlement location and are thus not lost to the assay. The assay geometry lends itself to assessing cyprid exploration and settlement on planar surfaces with chemical patterning, including relief microstructures, without using a confining material or requiring the coating of a three-dimensional well.

Correlation between surface chemistry and settlement behaviour in barnacle cyprids (Balanus improvisus)

“…Variation in the behaviour of cyprids (encountering the meniscus more frequently, for example) or differences in the composition/physical nature of the cuticle may further explain the phenomenon. Similar findings were described by Petrone et al (2013), comparing settlement results from a sessile drop assay, glass vials and opposed glass surfaces.…”

Effect of Multilayer Termination on Nonspecific Protein Adsorption and Antifouling Activity of Alginate-Based Layer-by-Layer Coatings

“…Three-day-old cyprids were used in settlement experiments. Because of the very hydrophilic nature of the materials provided, a recently established assay geometry was used . Briefly, a “sandwich” of two coated microscope slides was arranged, with the slides separated by ∼1.5 mm using plastic spacers.…”

Chemistry-specific surface adsorption of the barnacle settlement-inducing protein complex

“…Advancing water contact angles were 107 + 18 for CH 3 , 60 + 28 for N(CH 3 ) 3 þ , 45 + 38 for COO 2 , 39 + 28 for OH and 33 + 28 for OEG. Additional information on ellipsometric thicknesses, surface free energies and infrared reflection absorption spectra can be found in [17][18][19][20].…”

“…The location of the stained fraction (well number), relative to the standards mentioned above, provided a measure of the pI of the SIPC. ellipsometric thicknesses, surface free energies and infrared reflection absorption spectra can be found in [17][18][19][20].…”