Polycaprolactone pcl

Polycaprolactone (PCL, Mw = 45,000, Sigma-Aldrich, USA) nanofibers were fabricated by electrospinning as we should before^{56 (link),62 (link),63 (link)}. The concentration of PCL (3% w/v) was chosen based on our previous studies that optimized the PCL w/v % to maximize the mechanical properties of the scaffold, preserve the cellular functions and the bioactivity of loaded growth factors. Collagen ASCs-encapsulated constructs were prepared and deposited around silicone posts as previously described. Polymerized constructs were incubated for two days in cell culture conditions. PNCOL ASCs-encapsulated constructs were prepared and deposited around polymerized collagen rings to form a one unit scaffold composed of two concentric layers. Biphasic scaffolds were then incubated overnight before they were subjected to mechanical loading. Figure 9 depicts a visualization of the biphasic scaffolds collected after 7 days of mechanical loading in culture conditions and a schematic representation of the biphasic scaffolds.

Three types of polymers were used for fabrication of nanofibers and films: Poly(caprolactone) (PCL) (Sigma-Aldrich (Saint Louis, MO, USA), Mw = 80,000 g/mol, Tg = −60 °C), poly(l-lactide) (PLLA) (PL49, Corbion (Amsterdam, The Netherlands,), inherent viscosity = 4.9 dL/g, Tg = 58 °C), and poly(l-lactide-co-caprolactone) (PLCL) 70:30 (Resomer^® LC703S, Evonik (Weiterstadt, Germany), inherent viscosity = 1.3–1.8 dL/g, Tg = 32–42 °C). Solvents—acetic acid (AA) (purity degree 99.5%), formic acid (FA) (purity degree ≥ 98%), and hexafluoroisopropanol (HFIP) (purity degree 98.5%) were purchased from Poch (Gliwice, Poland), Sigma-Aldrich (Saint Louis, MO, USA), and Iris Biotech GmbH (Marktredwitz, Germany), respectively. Ethylenediamine (purity degree 99.5%), isopropanol (purity degree 99.8%), ninhydrin (purity degree 99%), and ethanol (purity degree 99.8%) were purchased from Chempur (Piekary Śląskie, Poland). For PCL and PLLA, glass transition temperatures were determined experimentally. Glass transition temperature of PLCL was assumed as stated by the producer.

Electrospinning was performed using an optimized protocol described previously [19 ]. The electrospinning solution for 100% PCL fibers was formed from a 10% (w/v) solution of PCL (MW: 70 kDa—90 kDa, Sigma, St. Louis, MO) in a 50:50 mixture of dichloromethane and dimethylformamide (Fisher Scientific, Pittsburg, PA). Electrospinning solutions used to form PCL+Gel fibers were made from polycaprolactone (PCL, Sigma, St. Louis, MO) and type A gelatin (Sigma) in a 90/10 (w/w) ratio dissolved in Trifluoroethanol (Fisher Scientific, Pittsburg, PA) with 1% acetic acid (Fisher Scientific) to improve miscibility [12 (link)]. The PCL+Gel concentration was 10% (w/v) in the electrospinning solution. Either polymer solution was loaded into a 10 mL syringe with a 25 Gauge needle and extruded at a rate of 0.5 mL/hr into a high voltage electric field. The applied static electric potential was +17kV relative to a grounded cylindrical collector 20 cm away. The collector was rotated at high RPMs to collect highly aligned fibers or at very low RPMs to produce randomly oriented fibers. After electrospinning, each sample was put in a vacuum desiccator overnight to remove any residual solvent.

Polycaprolactone (PCL; Sigma-Aldrich, UK) and gelatine from porcine skin (Ge; Sigma-Aldrich, Saint Louis, MO, USA) were used to synthesise the polymer solutions listed in Table 2. PCL and Ge were each dissolved at 8, 10 and 12% w/v concentration in trifluoroethanol (TEF; Sigma-Aldrich, Saint Louis, MO, USA), and then combined in the following PCL solution:Ge solution ratios: 85:15, 70:30 and 50:50. Solutions were magnetically stirred (110 rpm) overnight at room temperature and visually examined to verify homogeneity prior to electrospinning.

Polycaprolactone (PCL) (M_n 2000 and 530 Da) was purchased from Sigma–Aldrich; 1,6-hexamethylene diisocyanate (HDI), 1,4-butanediol (BDO), 1,2-dicholoethane, stannous octoate, curcumin (Cur) and 1,1,1,6,6,6-hexafluoroisopropanol (HFIP) were purchased from Merck Co. PCL and BDO were dried prior to use under vacuum at 80 °C for 24 h.

The polymer used as the matrix in this study was polycaprolactone (PCL) with Mn = 80,000 (Sigma Aldrich, St. Louis, MO, USA), while the added component was cefuroxime (CF) (Astro Pharma, Vienna, Austria). The solvents used were glacial acetic acid and acetone (Ru-Ve, Sveta Nedelja, Croatia). Titanium dioxide (TiO₂), nano (n-TiO₂ particles 21 nm, Aeroxide P25) and micro (m-TiO₂ particles 0.1 µm to several µm) powder, were supplied by Sigma-Aldrich, St. Louis, MO, USA. The polymer solution concentration was 18%, while the concentrations of the antibiotic CF were minimum of 5 and maximum of 25 wt %. The blend PCL/CF solution was prepared by dissolving the two components in the blend solvents (volume ratio 8:2). The solution was homogenized by constant stirring, for more than 24 h at room temperature and for up to one hour, with heating at 50 °C when the antibiotic was added.