(W0930-10-57) Biodegradable Electrospun Nanofibrous Scaffolds for Retinal Tissue Engineering: Fabrication and Characterization

Purpose: Retinal diseases constitute a leading cause of vision impairment and loss for millions globally. Tissue engineering (TE) has recently emerged as a promising alternative to repair retinal damage and restore its functions.¹ The design of scaffolds with proper physicochemical and mechanical properties which allow cells to grow & proliferate to regenerate damaged retinal tissues is paramount for the regeneration of retinal tissues. Therefore, this work aims to fabricate and characterize polycaprolactone (PCL) based biodegradable electrospun nanofibrous scaffolds (BENS) capable of carrying antibiotics, protein, and other hormonal therapy for retinal tissue engineering applications.

Methods: BENS were made using various weight percentage ratios of PCL and polyethylene glycol 35000 (PEG35000) biodegradable polymers. The BENS prepared were either blank or loaded with Amoxicillin (AMX) as a representative antibiotic agent. Scanning Electron Microscopy (SEM) was used to determine prepared fibers' morphology, surface topography, and diameter. To identify the nature of the interaction between the incorporated polymers and the loaded drug, Fourier Transform Infrared (FT-IR) spectroscopy was used. Differential Scanning Calorimetry (DSC) was utilized to assess the thermal behavior of prepared BENS and the degree of crystallinity. X-Ray Diffraction (XRD) was carried out to identify the fibers' crystalline pattern changes. The prepared BENS were subjected to mechanical testing using a tensile tester to determine their elasticities and tensile strengths.

Results: Various weight percentage ratios of PCL and PEG using chloroform as a solvent were prepared and further subjected to electrospinning to prepare the BENS. Thermal analysis before and after electrospinning showed melting peaks between 59-62 ^oC for PCL and 66-68 ^oC for PEG. There were no significant changes in the melting points for both constructed fibers following their electrospinning. The FT-IR showed that all the major groups for PCL and PEG blank BENS were present following their electrospinning, indicating that the process did not affect their chemical nature. The mix of polymers in which PCL constituted 75% w/w/ ratio resulted in the optimal transparency and mechanical strength required for the retinal TE with ultimate tensile stress of 2.5±.14 MPa, elongation % of 293±31.33, and Young's modulus of 0.93±0.2 MPa. This ratio was further used in the preparation of the drug-laden BENS. The DCS, FT-IR, and XRD studies confirmed AMX loading in the BENS and dispersion in its amorphous state.

Conclusion: The newly prepared PCL-based BENS possess the ultimate needed morphological, physicochemical, thermal, and mechanical properties that make them promising candidates for retinal TE applications with capabilities of ease loading of antibiotics and other drugs to them in their amorphous state. Future in vitro cell culture and in vivo animal studies are future plans to confirm the suitability of such BENS in retinal TE applications.

References: 1- Abedin Zadeh et al. Drug Discov Today. (8):1669-1678. 2019 doi: 10.1016/j.drudis.2019.04.009.

Acknowledgements:This work was made possible by an NPRP award [NPRP13S-0126-200173] from the Qatar National Research Fund (a member of the Qatar Foundation) granted to H. Younes. The statements made herein are solely the authors' responsibility(s).