Electrospun nanofibers for antibiotic and probiotic co-delivery to target bacterial vaginosis

Despite initial success, antibiotic therapy for bacterial vaginosis (BV) often fails within a year to prevent recurrence. Probiotic therapy has shown promise, but inconvenient and frequent administration may affect user adherence. Recently, probiotic (lactobacilli) therapy alone was shown insufficient to dislodge fastidious anaerobic bacteria such as Gardnerella. Nanofiber devices offer a means for controlled delivery of active agents for vaginal application. This study developed a novel nanofiber vehicle for antibiotic and probiotic co-delivery with the goal of targeting anaerobes while simultaneously promoting lactobacilli. Nanofibers were designed with 3:1 v/v PEO:PLGA ratio in a meshed architecture. Fibers were loaded with 7.5 mg metronidazole and 8.33x10⁷ CFU L. crispatus per mg of material and characterized via SEM imaging and thermal analysis. Metronidazole burst release into simulated vaginal fluid and sustained L. crispatus recovery over 6 days in MRS broth were measured. Nanofiber inhibition of Gardnerella in coculture was assessed via serial dilutions. Metronidazole was released up to 93.95% of the theoretical load within 20 min. Cumulative recovery of metabolically active L. crispatus of 1.33x10⁹ CFU/mL corresponded with lactic acid reaching 7.50 mg/mg of fiber for 6 days. Gardnerella exposed to fibers in coculture were cleared by 24 hr while L. crispatus recovery reached 8.71x10⁸ CFU/mL. VK2/E6E7 cells exposed to fibers in coculture showed minimal LDH release comparable to untreated. Overall, the results support the feasibility of antibiotic and probiotic co-delivery via electrospun nanofibers designed for staged release, with the longer term goal to target BV while promoting user adherence.