Double sided carbon tabs

A 0.5 cm x 0.5 cm piece of foil, on which the fibers were collected, was adhered onto an SEM stub, using double sided carbon tabs (Agar Scientific, Stansted, UK). The prepared stub was then given a thin coating of gold (10 nm) using a Quorum Q150T Sputter Coater (Quorum Technologies Ltd. East Sussex, UK) in an argon atmosphere. The coated stub was then transferred and imaged under FEI Quanta 200F (FEI company Ltd, Eindhoven, The Netherlands), at an acceleration voltage of 5 kV. Fiber size analysis was performed by measuring the diameter of these fibers using ImageJ software (National Institute of Health, Maryland, USA).

The morphology of SIRC cells proliferated on the blank and drug-loaded coaxial nanofibers were demonstrated using a modified SEM method of Sun et al. (2014) and He et al. (2018) . The fibers were incubated (37 ᵒ C and 5% CO 2 ) with the cells for 24 hours, then were rinsed with Dulbecco's PBS then removed from the well and transferred to a new well, with no media. This material was kept in the incubator at 37 ᵒ C and 5% CO 2 for a maximum of 5 minutes, in order to dry the fibers from the remaining buffer. The dried fibers were then adhered onto an SEM stub, using double sided carbon tabs (Agar Scientific, Stansted, UK). The prepared stub was then given a thin coating of gold (10 nM) in a Quorum Q150T Sputter Coater (Quorum Technologies Ltd. East Sussex, UK) in an argon atmosphere. The coated stub was then transferred and imaged under FEI Quanta 200F (FEI company Ltd, Eindhoven, The Netherlands), at an acceleration voltage of 5 kV.