A comparison of contact angle measurement results obtained on bare, treated, and coated alloy samples by both dynamic sessile drop and Wilhelmy method

The goal of this work was to compare the performance of our home-built dynamic sessile drop contact angle (CA) goniometer with our NIMA Dynamic Surface Tensiometer. Water CA measurements on different alloy samples (aluminium brass, copper-nickel 70/30, stainless steel 304) have been carried out by 1) sessile drop and 2) Wilhelmy plate method. Different sets of substrates were i) cleaned; ii) cleaned and pre-treated; iii) cleaned, pre-treated and coated with atactic polystyrene. During these experiments, the main features of the two setups in connection with our sample properties were understood. We therefore found it desirable and justified to sum up our findings

A comparison of contact angle measurement results obtained on bare, treated, and coated alloy samples by both dynamic sessile drop and Wilhelmy method

The goal of this work was to compare the performance of our home-built dynamic sessile drop contact angle (CA) goniometer with our NIMA Dynamic Surface Tensiometer. Water CA measurements on different alloy samples (aluminium brass, copper–nickel 70/30, stainless steel 304) have been carried out by 1) sessile drop and 2) Wilhelmy plate method. Different sets of substrates were cleaned; cleaned and pre-treated; cleaned, pre-treated and coated with atactic polystyrene. During these experiments, the main features of the two setups in connection with our sample properties were understood

Stimuli-Responsive Membrane Anchor Peptide Nanofoils for Tunable Membrane Association and Lipid Bilayer Fusion

Self-assembled peptide nanostructures with stimuli-responsive features are promising as functional materials. Despite extensive research efforts, water-soluble supramolecular constructs that can interact with lipid membranes in a controllable way are still challenging to achieve. Here, we have employed a short membrane anchor protein motif (GLFD) and coupled it to a spiropyran photoswitch. Under physiological conditions, these conjugates assemble into ∼3.5 nm thick, foil-like peptide bilayer morphologies. Photoisomerization from the closed spiro (SP) form to the open merocyanine (MC) form of the photoswitch triggers rearrangements within the foils. This results in substantial changes in their membrane-binding properties, which also varies sensitively to lipid composition, ranging from reversible nanofoil reformation to stepwise membrane adsorption. The formed peptide layers in the assembly are also able to attach to various liposomes with different surface charges, enabling the fusion of their lipid bilayers. Here, SP-to-MC conversion can be used both to trigger and to modulate the liposome fusion efficiency