2.4 Fabrication of PLGA/GelMA fibers on PTMC/TPU scaffolds
15 w/v% PLGA, 5 w/v% GelMA and 0.5 w/v%
2-hydroxy-2-methylpropiophenone were dissolved in HFIP solvent to
prepare a PLGA/GelMA solution for electrospinning. The solution was then
transferred to a 10 ml syringe equipped with a steel needle with an
inner diameter of 0.8 mm. The syringe was fixed to a pump (LongerPump,
LSP01-3A, UK). The steel needle was connected to a high-voltage power
supply (Kou Hing Hong Scientific Supplies Ltd., HK). To determine the
optimal parameters for electrospinning of PLGA/GelMA fibers, different
applied voltages (10, 15, 20 kV) and feeding rates (0.5, 1.0, 2.0 ml/h)
were investigated. The 3D printed PTMC/TPU scaffolds were attached to an
aluminum foil. The aluminum foil was connected to the high-voltage power
supply and was placed 10 cm away from the needle tip to collect
electrospun PLGA/GelMA fibers on the PTMC/TPU scaffolds. The bilayer
scaffolds thus formed were exposed to a UV light (365 nm) for 10 min and
then incubated in an oven at 50 ℃ overnight. In the current study, these
bilayer scaffolds were designated as S+F scaffolds. The fabrication of
S+F-PDA scaffolds was similar to the above process but with different
concentrations (0.5, 1.0, 2.5 and 5.0%, with the concentration
referring to the PDA mass to the total mass of PLGA and GelMA) of PDA
particles dispersed in the PLGA/GelMA electrospinning solution.
The surface morphology and diameters of electrospun PLGA/GelMA fibers
and PLGA/GelMA-PDA fibers were studied using SEM. The mechanical
properties of PLGA/GelMA and PLGA/GelMA-PDA fibers were investigated via
tensile tests. Moreover, the surface and cross-sectional morphology of
S+F-PDA scaffolds were examined through SEM. The mechanical performance
and shape morphing behavior of bilayer scaffolds were also investigated.