Cinnamaldehyde- and meropenem-enriched 3D-printed corneal scaffolds for bacterial keratitis

Abstract This study describes the development of three-dimensional (3D) printed sodium alginate/gelatin (SA/GEL) corneal scaffolds loaded with cinnamaldehyde (CA) and meropenem (MER) for the treatment of bacterial keratitis. The scaffolds were fabricated using extrusion-based 3D printing and characterized in terms of their morphological (SEM), chemical (FTIR), thermal (DSC), and mechanical properties. In vitro assessments were conducted to evaluate the drug-release profiles, antibacterial properties, antibiofilm properties, and cytocompatibility. SEM analysis revealed the following pore sizes for the different scaffold formulations: 319.49 ± 20.78 µm for SA/GEL, 203 ± 15.35 µm for SA/GEL/MER, 251.06 ± 28.21 µm for SA/GEL/CA, and 264.39 ± 43.16 µm for SA/GEL/CA/MER. These pore sizes are suitable for corneal tissue engineering, as they support fibroblast attachment and facilitate wound healing. Mechanical testing demonstrated that the tensile strength of the drug-loaded scaffolds remained within a range comparable to that of native corneal tissue, indicating their potential for use in clinical applications. Antibacterial and antibiofilm assays indicated that the incorporation of CA significantly enhanced the antimicrobial efficacy of MER against Pseudomonas aeruginosa and Staphylococcus aureus , with biofilm inhibition rates reaching 92% and 90%, respectively. Drug-release studies revealed that MER was released within 48 h, while CA exhibited a more sustained release greater than 72 h. These findings highlight the strong potential of CA- and MER-loaded SA/GEL scaffolds as dual-function biomaterials, capable of both infection control and corneal tissue regeneration. The combined antibacterial and antibiofilm properties of the scaffolds make them promising candidates for treating corneal injuries and bacterial keratitis in future tissue-engineering applications. Graphical abstract