Bicomponent polycaprolactone/gelatin (PCL/Gt) nanofibers were successfully formed for the first time by electrospinning using a novel polymer–solvent system with solvents being alternative to the commonly used toxic solvents like fluorinated alcohols. The mixture of acetic acid (AA) with formic acid (FA; 90:10) was applied. Stable electrospinning was possible despite the fact the mixture of PCL and gelatin in AA/FA solvent showed emulsive structure. From the practical perspective, there is no doubt that it is possible to obtain PCL/Gt fibers using AA/FA mixture with morphology similar to that for fibers spun from hexafluoroisopropanol (HFIP) solutions. GRAPHICAL ABSTRACT

Two types of poly(glycerol sebacate) (PGS) prepolymers were synthesized and electrospun with poly(l-lactic acid) (PLA), resulting in bicomponent nonwovens. The obtained materials were pre-heated in a vacuum, at different times, to crosslink PGS and investigate morphological and structural dependencies in that polymeric, electrospun system. As both PGS and PLA are sensitive to pre-heating (crosslinking) conditions, research concerns both components. More interest is focused on the properties of PGS, considering further research for mechanical properties and subsequent experiments with PGS synthesis. Electrospinning of PGS blended with PLA does not bring difficulties, but obtaining elastomeric properties of nonwovens is problematic. Even though PGS has many potential advantages over other polyesters when soft tissue engineering is considered, its full utilization via the electrospinning process is much harder in practice. Further investigations are ongoing, especially with the promising PGS prepolymer with a higher esterification degree and its variations.