Oriented Electrospun Fibers of Poly(pro-curcumin/PEG) Sequester Reactive Oxygen Species and Promote the Growth of Schwann Cells

In the biological injury microenvironment, pathologically elevated oxidative stress hinders healthy cell migration. Aligned electrospun fibers are used as tissue engineering scaffolds to support and guide the directionality of cell migration. The ability of cells in the central nervous system to sequester and quench reactive oxygen species is limited, and most electrospun fibers do not exert any antioxidant activity on contact. Thus, the challenge remains in designing a scaffold that can both guide cells to the injury site as well as sequester and quench excess free radicals, allowing cells to thrive and potentially regenerate. Curcumin is a well-known, potent antioxidant, but it suffers from a short half-life in vivo, poor solubility, and low bioavailability. Polymerizing curcumin as a poly(pro-drug) enhances stability while preserving bioactivity over vastly extended time scales (months to years). Here, we present highly aligned bioactive electrospun fibers composed of poly(curcumin-co-polyethylene glycol (PEG)). This study first optimized electrospinning conditions (solvent, voltage, spin time, speed, gap distance, and flow rate) to produce stable and well-aligned electrospun fibers. We also showed that the fibers retained their antioxidant function even after the electrospinning process, through a colorimetric free radical quenching assay. Intriguingly, the fiber mats exert radical-sequestering activity immediately on contact, as opposed to solid films composed of the same poly(curcumin-co-PEG) material, presumably due to the much higher solvent-accessible surface area in the fibers. Finally, we find that Schwann cells preferentially adhere more robustly when cultured directly onto the aligned poly(curcumin-co-PEG) fibers compared to poly-L-lactic acid fibers. Our successful fabrication and characterization of these poly(curcumin-co-PEG) electrospun fibers demonstrate potential for future biomedical and tissue engineering applications.