MSc.Thesis Defense: Sümeyye NARİN

FABRICATION OF ELECTROSPUN POLY(GLYCEROL SEBACATE) (PGS) SCAFFOLDS FOR CORNEAL TISSUE ENGINEERING

Sümeyye NARİN
Materials Science and Nano Engineering, MSc. Thesis, 2024

Thesis Jury

Asst. Prof. Sibel ÇETİNEL (Thesis Advisor), Assoc. Prof. Gözde İNCE

, Assoc. Prof. Sakip ÖNDER

Date & Time: 18th of July, 2024 –  13.30 AM

Place: L027

Zoom Linki: https://sabanciuniv.zoom.us/j/5676619913?pwd=WEljZ2dIdzFXampGQlVIQnpRN3Fxdz09&omn=94457931662

Keywords : electrospinning, artificial tissue, transparent membrane, fiber, elastomer

Abstract

The demand for tissue engineering of cornea grows daily. Various applications have been implemented to meet this need with biomaterials  such as polymers. Amongst those polymers, poly (glycerol sebacate) (PGS) has been used to perform various tissue engineering applications owing to their biodegradable, biocompatible, elastomeric, transparent, and pro-regenerative properties. Electrospinning of PGS would enhance the mechanical strength, permeability, and cell attachment to the scaffold. Electrospinning PGS alone remains challenging due to its very low molecular weight (MW) and low glass transition temperature (Tg). Thus, carrier polymers like poly (vinyl alcohol) (PVA) have been widely used in PGS electrospinning research. For these reasons, in this work, blending of PGS and PVA as a supporter polymer in electrospinning was investigated to mimic corneal membranes. The best blending ratio with the optimized electrospinning parameters was determined to be 55% PGS and 45% PVA. Because of the thermal crosslinking property of the PGS, a crosslinking temperature of 160°C led to the best performance in terms of fiber stability, porosity and membrane transparency amongst temperatures of 140, 150,  160 and 170°C. After crosslinking, PVA ought to be removed to increase transparency of the membranes. Therefore, several washing methods were applied and the most PVA removal was obtained through 48 h water wash at room temperature (RT). The membranes obtained by this process had resulted in 28% porosity with average fiber diameter of 4 µm; and the mechanical strength of the membranes was found to be 1.2 MPa with a 20% strain. Moreover, the measured permeability of the membranes on average was 8.57E-07 which is highly close to the actual permeability of cornea as 3.02E-06. Results of cytotoxicity tests were performed with human corneal epithelial cells (HCEpC) indicated that cells were almost 50% viable after 3 weeks of incubation time. As a result of optimized electrospinning of PGS:PVA blend, we obtained a microporous, tough and biocompatible membrane.