Injekt f solo

The interactions between modified calcite
surfaces and water were measured using an optical contact angle device
(OCA40, Data Physics Instruments GmbH) equipped with a standard operating
table and automated micropipette with a disposable silicone oil- and
latex-free syringe of volume 1.0 mL (Injekt-F Solo, B. Braun Melsungen
AG) and a passivated stainless-steel tip of inner diameter 0.15 mm
(30 GA GP, Optimum, Nordson EFD). The droplet shape was recorded by
a high resolution CCD camera at a rate of 6 frames/s. The average
of the CAs on the left and right sides of the droplet was calculated
using the ellipse fitting method in the SCA20 software (DataPhysics
Instruments GmbH).
All CA measurements were carried out just
after the surface treatment process was completed. At least five calcite
samples were analyzed in parallel for each condition, where each sample
could fit 2 to 4 independent water droplets. After the deposition
of a 1 μL droplet, the contact angle was measured as a function
of time. The initial value was set at 1.2 s from the droplet contact
with the surface, while for stearic acid, a semistatic contact angle
was read after 30 s, as the initial fast spreading of the droplet
at this stage was complete. All measurements were carried out under
ambient air, where the temperature varied between 21.5 and 24.5 °C,
and the humidity was around 50% RH.

Homogenized precursor mixtures (see Section 2.4.1 and Section 2.4.2) were introduced airtight into a sterile syringe (1 mL Injekt-F Solo, B Braun, Melsungen, Germany), and the electrospinning process was carried out with the Spincube (Spinsplit LLC, Budapest, Hungary) laboratory electrospinning device using a single needle emitter. During the electrospinning experiments 20 kV of voltage was applied to the precursors at 15 cm collector-emitter distance and 20 μL min⁻¹ feed rate using HydroDrive to minimize precursor waste. The experiments were carried out at room temperature. Nanofibrous samples were stored at 4 °C in a refrigerator prior to use. The electrospinning process resulted in a lipase content (loading) of 10 wt% in all the nanofibrous products.