G-3210

Development of synthetic polyurethane / alginate electrospun scaffold containing zinc oxide nanoparticles for oral wounds

 Amirmohammad Roldar ¹, Arshia Ali Abadi ¹, Mohammad Mokhtarifar ², Sajad Alavimanesh ³ ℗, Azita Azad ⁴ ©   

 
Abstract

Introduction Chronic oral ulcers can impair nutrition, speech, and quality of life. Tissue-engineering scaffolds that unite biocompatible polymers and bioactive nanoparticles can accelerate mucosal repair. This study aimed to fabricate and characterise an electrospun polyurethane/alginate (PU/Alg) scaffold loaded with zinc-oxide (ZnO) nanoparticles for oral-wound applications. Materials and Methods: PU/Alg (3 % w/v) was dissolved in dimethylformamide and electrospun through a dual-nozzle system (22-G needle; 15 cm gap; 20 kV; 1 mL h⁻¹). ZnO nanoparticles were co-electrospun and fibres vapour-cross-linked with glutaraldehyde to enhance stability. Morphology and porosity were assessed by scanning-electron microscopy (SEM). Tensile properties (Young’s modulus, ultimate tensile strength, elongation at break) were measured with an Instron 5566 (50 N load cell, 5 mm min⁻¹). Degradation was followed as weight loss in phosphate-buffered saline (PBS, 37 °C) for 28 days. Hydrophilicity was quantified by water-uptake percentage and static contact-angle goniometry. Biocompatibility was examined via MTT assays on two mammalian cell lines (dental-pulp stem cells and fibroblasts) seeded onto 5 × 5 mm scaffolds for 24–72 h, and early adhesion was probed at 3 h and 24 h. Data are mean ± SD; one-way ANOVA with Bonferroni correction (GraphPad Prism 9) defined significance at p 0.05. The protocol was approved by the Ethics Committee of Shiraz University of Medical Sciences (IR.SUMS.REC.1401.501). Results: SEM revealed uniform, bead-free nanofibres forming highly interconnected pores; mean porosity reached 84 %—ideal for cell ingress. Mechanical testing showed PU/Alg + ZnO scaffolds possessed a Young’s modulus of 0.39 ± 0.06 MPa, ultimate tensile strength of 0.71 ± 0.30 MPa and elongation at break of 38 ± 2.8 %, all significantly higher than collagen controls (p 0.05). Degradation was gradual: 10 % weight loss over 28 days versus 15 % for collagen (p 0.05), indicating sustained structural integrity. Contact-angle analysis demonstrated a more hydrophilic surface for PU/Alg (65°) compared with collagen (75°, p 0.05); nevertheless, its water-uptake capacity remained lower, supporting controlled moisture balance. MTT assays showed 90 % cell viability at 24, 48 and 72 h with no significant difference from collagen. Early adhesion assays confirmed superior attachment on PU/Alg fibres at 24 h. Discussion and Conclusion: Electrospun PU/Alg/ZnO scaffolds exhibit high porosity, improved mechanical strength, controlled degradation, favourable hydrophilicity and excellent cytocompatibility. ZnO nanoparticles should additionally provide antimicrobial protection. These combined attributes make the composite scaffold a strong candidate for promoting oral-mucosal wound healing and justify subsequent in-vivo studies.

Keywords: Tissue engineering; Polyurethane; Zinc-oxide nanoparticles; Electrospinning; Oral wound healing