Dsa100 goniometer

The wettability of the electrospun scaffolds was assessed using Kruss system (DSA 100 goniometer) with static sessile drop. Samples were held horizontally on glass slides within the field of view, and an 8 μL droplet of distilled water released from an 8-gauge needle onto the scaffold surface. Sample wettability (n = 5) was tested before and after 12 h treatment in cell culture media (Dulbecco’s Modified Eagle’s medium, DMEM, Sigma-Aldrich) supplemented with 10% fetal bovine serum (FBS; Gibco). Before testing, samples were vacuum-dried at room temperature for 4 h.

Hydrophilic properties of PDA-modified PU fibers were studied using the sessile drop method (DSA100 goniometer, Krüss GmbH, Hamburg, Germany). Then, 5 μL distilled water droplets were dispensed on the surface of the fibrous material (about 1.6 cm²), and the images of droplets were taken every 1 s with the digital camera. The time from the contact of a water droplet with the surface of PDA-modified fibrous material to complete the imbibition of the droplet from the surface to the material structure was defined as a “water droplet imbibition time.” (See measurement Videos S1–S3 in Supplementary Materials) The unmodified fibrous material was used as a control. All measurements were carried out for three independent samples for each tested variant, and water contact angle values and water droplet imbibition time values are presented as mean ± standard deviation.
Time stability of the hydrophilic properties of PDA-modified PU fibrous material was examined by measuring the water droplet imbibition time as a function of material storage time. Selected samples (V-I, 8 h of the modification, V-II, 0.5 h of modification) were stored in closed ventilated Petri dishes under atmospheric conditions at room temperature. After 1, 2, 3, 5, 7, 14, 21, and 28 days of sample storage, the water droplet imbibition time was measured according to the methodology described above.

Contact angle analysis (WCA) was performed by the sessile drop technique at room temperature and atmospheric pressure with a Krüss DSA100 goniometer (Hamburg, Germany). Three independent measurements were performed for each sample, each with a 5 µL water drop, and the obtained results were averaged to reduce the impact of surface nonuniformity.

Contact angle measurements were performed to determine the surface hydrophilicity (wettability) of the membranes. Drop shape analysis (DSA) was used to determine the contact angles of the membranes using a DSA 100 goniometer (Krüss GmBH, Hamburg, Germany) to investigate the extent to which water interacts with the surfaces. The membrane samples (three each) were placed onto the sample stage and measurements of sessile drops taken on more than ten positions and averaged.