Sulfonated polyethersulfone nanofibers as new scaffold for regenerative medicine applications

Modifying physicochemical properties of polymers through functionalization is a practical approach in the preparation of tissue engineering scaffolds. The aim of present research is to sulfonate polyethersulfone and to improve its biocompatibility in order to regulating cell behaviors. Sulfonated polyethersulfone with different degrees of sulfonation were prepared using three different concentrations of chlorosulfonic acid as the sulfonating agent. The degree of sulfonation was investigated quantitatively and qualitatively. The electrospun nanofibers were fabricated by prepared polymers afterward. Morphological properties, contact angle, and porosity of nanofibrous scaffolds were studied. The adhesion, growth and proliferation of cultured mesenchymal stem cells on the scaffolds were investigated. Polyethersulfone was sulfonated with three molar percentages of 14.2, 22.1, and 30.1, based on the titration results. The scanning electron microscopic images of nanofibers showed that polyethersulfone nanofibers at a concentration of 25% W/V had a uniform and beadless structure. The diameter size distribution of sulfonated polyethersulfone nanofibers was uniform with a flow rate of 0.09 ml/h. Sulfonation significantly changed many properties of the final scaffold. The water contact angle decreased from 130◦ to 117◦, 108◦, and 100◦, after sulfonation. The diameter of nanofibers decreased from 391 nm to 192 nm, 140 nm, and 121 nm. Cell studies showed that sulfonation of polyethersulfone nanofibers improves adhesion, and increases the growth and proliferation of stem cells. However, the degree of sulfonation must remain at an optimal level. As a result sulfonation is a suitable method to improve the properties of synthetic polymers such as polyethersulfone for biological applications.