Innovative Antibacterial Wound Dressings: Coaxial Electrospun Nanofibers with Shikonin and Cresol

Coaxial electrospun PVP nanofibers co‑delivering shikonin and cresol show retained antibacterial activity and a rapid burst‑release profile in vitro, supporting further translational evaluation for early infected skin wounds.

Unlike passive coverings or single‑agent antimicrobial dressings, this core-shell construct pairs a botanical anti‑inflammatory (shikonin) with a phenolic bactericide (cresol) to deliver both activities directly at the wound interface. By concentrating drug release locally, the design may maximize early antimicrobial and anti‑inflammatory effects while limiting systemic exposure.

SEM showed smooth, non‑beaded fibers (mean diameter 772 ± 152 nm), and TEM confirmed the core–shell morphology. XRD and spectroscopy indicated molecular dispersion of the drugs. Quantified loading and encapsulation was EE 44% ±1, DL 25 ±1 µg/mg for shikonin and EE 38% ±1, DL 21 ±0.5 µg/mg for cresol. In vitro release featured a pronounced burst (≈73% shikonin, ≈85% cresol within 10 minutes) with complete release by ~180 minutes.

Antibacterial testing showed particular potency against Gram‑positive organisms. Shikonin MICs were 3 µg/mL for S. aureus and 6 µg/mL for MRSA; a 1:1 shikonin/cresol combination achieved MICs of 3 µg/mL for both strains, whereas cresol alone required substantially higher concentrations (≈1500 µg/mL for some Gram‑positive isolates). Zone‑of‑inhibition assays produced diameters comparable to the free drugs, and standard MIC microbroth dilution and agar assays confirmed retained activity after electrospinning—consistent with a rapid local bactericidal effect at the tested concentrations.

In vitro biocompatibility using human dermal fibroblasts (HFF‑1) showed the shikonin/cresol combination was tolerated at concentrations ≤6 µg/mL with cell viability above 50% at 24 hours; higher shikonin concentrations produced cytotoxicity. These short‑term in vitro safety data require in vivo and longer‑term assessment. Compared with standard dressings, the coaxial dual‑drug fibers offer active, combined release rather than passive coverage or single‑agent action—features that may suit early infected or inflamed wounds while underscoring remaining translational gaps.