Title : Optimizing melt electrospun PLGA fibers with CuSO4 to improve endothelial cell support
Abstract:
Background: Melt electrospinning is a promising solvent-free technique for fabricating microfibrous scaffolds with controlled fiber design. However, its application is limited by the poor electrical conductivity of many polymers, including poly(lactic-co-glycolic acid) (PLGA). This limitation hampers fiber diameter control and the production of fine fibers (nano-scale), both of which are critical factors for cell viability and healing outcomes.
Objective: This study aimed to enhance the melt-electrospinnability of PLGA by increasing its electrical conductivity through the incorporation of copper(II) sulfate (CuSO4), thereby enabling the production of finer fibers with improved support for endothelial cells.
Methods: Various concentrations of CuSO4 (0, 1.5, 2, 3, 4, and 7% w/w) were incorporated into PLGA 50:50 (MW: 30-40 kDa) by thoroughly pre-melting the polymer with the salt. Fiber fabrication was performed using the melt electrospinning with R-GEN 100 bioprinter (REGENHU). Fiber morphology and diameter were assessed by optical microscopy and measured using Image J. The best fiber samples were selected to evaluate cell viability and fiber stability. Endothelial cells EAhy926 were seeded on the fibers at a concentration of (4x104 cells/ cm2) and cultured for 3 days. Cells were fixed with 4% PFA, stained with DAPI, and analyzed by fluorescence microscopy. Fiber stability was monitored through optical microscopy over time in the incubator.
Results: CuSO4 addition reduced fiber diameters from approximately 46 µm in neat PLGA to 7.6 µm with 1.5% CuSO4, reaching the smallest diameter of 2.5 µm in the sample with 3% CuSO4 . Higher CuSO? concentrations, starting from 4%, led to a slight increase in fiber diameter. PLGA composited with 3% CuSO4 was selected for stability and cell viability tests. Fibers containing 3% CuSO? demonstrated superior morphological stability during incubation, in contrast to neat PLGA, which exhibited swelling and loss of structural integrity. Furthermore, the reduction in fiber diameter promoted by the salt created a more favorable surface for endothelial cell attachment, resulting in nearly a two-fold increase compared to the neat PLGA.
Conclusion: Incorporation of CuSO? into PLGA significantly enhances its melt-electrospinnability by increasing electrical conductivity, enabling the production of finer and more stable fibers. Importantly, the effect is concentration-dependent, with 3% as the optimal dose, while higher concentrations slightly increase fiber diameter, likely due to particle agglomeration or changes in melt rheology.
Fiber stability is essential in biomedical applications, as scaffold integrity over time directly influences cell behavior, mechanical support, and tissue-regeneration outcomes. Notably, the 3% CuSO? fibers significantly supported endothelial cell attachment, emphasizing the importance of fiber diameter in cell-scaffold interactions. These findings provide a practical and effective way to overcome the limitations of using non-conductive polymers in melt electrospinning, underscoring the potential of this approach for vascular tissue engineering.
