Electrospinning of BSA mats: An electrospinning solution was prepared by dissolving BSA (MP Biomedicals) in 90% 2,2,2-trifluoroethanol (Apollo Scientific) for a final BSA concentration of 14% (w/v). After 12 h, 5% (v/v) β-mercaptoethanol (Alfa Aesar) was added. Electrospinning was performed in a custom-built system with a grounded collector. A 15 k V bias was applied on a 24gauge blunt needle with an injection rate of 1.5 ml/h. The needle was fixed 12 cm above the collector.