The pore size effect on the degradation, tensile properties and cell viability of polycaprolactone/starch scaffold: experimental study

Guided bone regeneration (GBR) membranes, which have many uses in dentistry, must have enough pore size to inhibit excessive connective tissue penetration into the bone defect on one side of the scaffold, while promoting neovascularization and bone growth on the other side. In this study, polycaprolactone (PCL) and starch were mixed with a ratio of 70:30 through the 3D bioprinting method which makes it possible to have an appropriate control on the pore size of the scaffold. SEM images showed that on the larger side, the pore size is around 370 µm, and on the other side of the scaffold, the average pore size is around 150 µm. Also, EDX analysis confirmed high concentrations of oxygen and carbon in the scaffold, indicating the presence of PCL and starch. Because of lipase's ability to catalyze the hydrolysis of ester bonds in PCL, the scaffolds that were immersed in phosphate-buffered saline (PBS) solution containing lipase showed a much higher degradation ratio (90%) after 28 days than those in PBS solution containing amylase (18%) or the combination of both (51%). These degradation ratios are much greater than the similar previous reports in which the scaffold had smaller pore size caused by other methods like electrospinning. The increase in pore size enhances degradation while maintaining acceptable levels of tensile strength (2.55 ± 0.29 MPa) required for GBR membranes.