A Combination of Gelatin Addition as the Sacrificial Fiber and Ultrasonication, to Increase the Pore Size of PCL-nHA ElectrospunScaffolds

Background and Aim: Electrospinning is one of the techniques inpreparation of the scaffolds for bone tissue engineering. However, due tothe small pore size of electrospun scaffolds, cellular infiltration and tissueingrowth into the scaffold are not possible. The use of sacrificial fibers(such as polyethylene oxide (PEO)) in a combination with ultrasonicationhas been shown as an appropriate way to increase the pore size of theelectrospun scaffolds in our previous work. But, due to the high cost ofPEO, it is not economical.Methods: In this study, gelatin (a water-soluble polymer) was chosenas a novel sacrificial agent and co-electrospun with polycaprolactonenanohydroxyapatite(PCL-nHA). Gelatin and PCL-nHA were coelectrospunon a rotating collector from two separated spinners. Afterelectrospinning, gelatin was washed with water for three days and then,the prepared scaffold was ultrasonicated. In order to find the optimizedratio of PCL-nHA and gelatin, the samples were weighed before and afterthe washing and the amount of lost weight was calculated. Morphologyand structural properties of the prepared scaffolds were studied bySEM. The mean pore size and fiber diameter were measured by ImageJsoftware. Fourier transform infrared (FTIR) spectroscopy and watercontact angle tests were used to evaluate the removal of gelatin.Results: According to the SEM results, the pore size of the scaffolds, aftergelatin removal and ultrasonication, was increased 3-folds comparedto the control sample (PCL-nHA without the addition of gelatin asthe sacrificial agent and ultrasonication), at PCL-nHA: gelatin ratio of70:30. Our results showed that an increase in the pore size, causedby the removal of gelatin, was approximately equal to that of PEO, inour previous work. FTIR results indicated incomplete gelatin removal.According to the contact angle results, due to incomplete gelatin removal,the samples were almost hydrophilic, although, after the removal ofgelatin, the hydrophilicity was less. Also, the contact angle after plasmatreatment showed that in both of the cases, they were hydrophilic.Conclusion: Our finding suggested that using gelatin as the sacrificialagent, is more appropriate for increasing the pore size of electrospunscaffolds.

Keywords:

PCL , Gelatin , Pore size , Co-electrospinning , Ultrasonication