Electrospun PBS scaffold fabrication and characterization

PBS scaffold was produced following the procedure previously published [16 (link)]. Briefly, a PBS (Poly(1,4-butylene succinate) extended with 1,6-diisocyanatohexane, Tm 120 °C, Aldrich, UK) solution (30 mL) in dichloromethane (15% w/v) was used to prepare each batch of the scaffold. The electrospinning process was carried out horizontally with 15 kV voltage (Spellman CZE 1000 R, Hauppauge, NY, USA) and a constant polymeric solution rate (0.8 mL/min) obtained through a programmable syringe pump (Aitecs PLUS SEP-21, Vilnius, Lithuania). The electrospun scaffold was collected on a stainless steel earthed rotating collector, positioned 15–20 cm away from the tip of the needle.
Molecular weight evaluation of PBS was carried out via size exclusion chromatography (SEC) by using an Agilent 1260 Infinity multi-detector GPC/SEC system. The elution was performed on a Phenogel 10⁴ column (Phenomenex, Torrance, CA, USA) using Hexafluoroisopropanol (Sigma-Aldrich, Gillingham, UK) as a mobile phase at 30 °C, with a flow rate of 0.6 mL/min. Standards of PEG were used for calibration. The average molecular weight (Mw) and polydispersity (Mw/Mn) resulted 294,500 and 1.4, respectively.