Contact angle goniometer

Scaffold hydrophilicity can impact the NAC release rate; therefore, the hydrophilicity of the nanofiber systems was evaluated using the DataPhysics Instruments contact angle goniometer by measuring the water contact angle using the sessile drop method. The nanofiber mats were placed on the testing plate and kept smooth. Subsequently, 2 µL of distilled water was dispensed onto the surface at a dosing rate of 2 µL/s using a Hamilton syringe. The images of the water droplet were recorded by camera software after the droplet was stable. Thereafter, the water contact angle was measured using the SCA202 version 4.1.12 build 1019 software. Five different samples were measured, and the average values were calculated. Drug entrapment efficiency, drug loading, and cumulative NAC release from the scaffolds was quantified by WinASPECT^® Spectro analytical Software (Analytik Jena AG, Jena) through ultraviolet spectroscopy at a wavelength of 224 nm.

Surface hydrophilicity was characterized using a sessile drop method with a contact angle goniometer type (DataPhysics, OCA, Filderstadt, Germany) at ambient temperature. UPW droplets of 2 µL were used to measure the contact angle of three different dried membrane samples on five different areas. Average values and standard deviations were calculated using both the right and left contact angles.

Energy-dispersive spectroscopy (EDS) and scanning electron microscopy (SEM, FE-SEM, S-4800, Hitachi, Japan) were used to detect the surface morphology and elemental composition of the scaffold, respectively. For both the Ti6Al4V and Ti2448 scaffolds, the scaffold was fixed on the tray with a conductive adhesive, and platinum was sprayed on the surface of the scaffolds by an E-1010 ion sputter-coating machine (SUPRO instrument) to improve the electrical conductivity of the material.
Surface roughness parameters of the Ti6Al4V and Ti2448 samples were analysed using an atomic force microscopy (AFM, SPM-9500J3, Japan). ACTA cantilever (Olympus) was used to scan the samples in non-contact mode. Size of images was recorded at 2 × 2 µm. Images were processed using SPIP software (Image Metrology A/S, Denmark) and roughness parameters were obtained from the scan size.
Water contact angle measurements were performed to analyse the hydrophilicity of the different surfaces. The surface water contact angle of Ti6Al4V and Ti2448 was detected with a contact angle goniometer (DataPhysics, Germany). Briefly, a distilled water dropt contacted the surface, and SCA20 software was used to record the shape of the droplet and calculate the water contact angle. To better detect the water contact angle and roughness on the surface of the material, we used solid scaffolds instead of porous scaffolds.