Screening of Parameters Affecting Mechanical Properties of Electrospun PCL/SEP/HAp Membrane

Objectives: To determine significant factors affecting the mechanical properties of a novel biomimetic electrospun polycaprolactone (PCL), soluble eggshell membrane protein (SEP), and nano hydroxyapatite (HAp) based GTR/GBR membrane, using Taguchi orthogonal arrays.
Methods: Electrospun PCL/SEP/HAp membrane specimens (n=16) were prepared with varying concentrations of PCL, SEP, HAp, and altered electrospinning parameters as generated by DOE software. The morphology and mechanical properties of all the specimens were evaluated using SEM and Sintech 2/G mechanical testing system. Based on the obtained tensile testing data, Taguchi orthogonal array L8 design (DOE folio, Weibull++ 2020 software, Reliasoft) was used to screen out significant factors affecting the mechanical properties of this composite membrane. The independent variables investigated were PCL wt%, SEP wt%, HAp wt%, applied voltage, flow rate of the solution and spinneret-collector distance with their corresponding values ranging between 12 wt% and 18 wt%, 1 wt% and 6 wt%, 0.5 wt% and 2 wt%, 13 kV and 18 kV, 0.4 ml/h and 1.4 ml/h, 8 cm and 13 cm. The response variables analyzed were tensile strength and elastic modulus.
Results: SEM analysis demonstrated bead-free uniform fibers with well dispersed HAp particles, for all the specimens. The elastic modulus and tensile strength values of tested specimens varied from 16.62 MPa to 207.3 MPa and 1.2 MPa to 3.5 MPa, respectively. ANOVA outlined SEP wt%, HAp wt%, applied voltage, flow rate, spinneret-collector distance and an interactive effect between PCL and applied voltage to be the significant factors affecting the elastic modulus of an electrospun PCL/SEP/HAp membrane (P<0.05). Furthermore, ANOVA results showed that there were no significant factors affecting the tensile strength. Also, except for applied voltage, all other significant variables had a positive correlation with elastic modulus.
Conclusions: Taguchi orthogonal arrays design outlined the significant variables and interactions affecting the mechanical properties of an electrospun PCL/SEP/HAp based GTR/GBR membrane.