Poly ε caprolactone pcl pellets

Poly(ε-caprolactone) pellets (PCL, Sigma-Aldrich, St. Louis, MO, USA) were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP, Sigma-Aldrich) to produce a 10 wt.% polymer solution (100 mg mL⁻¹). After overnight stirring, doxycycline (DOX, Sigma-Aldrich) was added at different concentrations (0, 5, 25, and 50 wt.%, relative to the total polymer weight); the mixtures were stirred for 24 h. The solutions were electrospun using an electrospinning system consisting of a high-voltage source (ES50P-10W/DAM, Gamma High-Voltage Research, Inc., Ormond Beach, FL, USA), a syringe pump (Legato 20, KD Scientific Inc., Holliston, MA, USA), and a grounded stainless steel collecting drum connected to a high-speed mechanical stirrer (BDC6015, Caframo Limited, Georgian Bluffs, ON, Canada). Each solution was loaded into a plastic syringe (5 mL, Becton, Dickson and Company, Franklin Lakes, NJ, USA) fitted with a 27G metallic blunt-tip (CML Supply LLC, Lexington, KY, USA) and electrospun using the following parameters: rotating mandrel (120 rpm of speed), fixed spinning distance of 18 cm, flow rate of 1.5 mL/h, and electric voltage of 15 kV. The obtained fiber mats were collected at room temperature and dried under vacuum for at least 48 h to complete removal of any remaining solvent.^{21 (link),22 (link)}