Antibacterial Properties of PLGA Electrospun Scaffolds Containing Ciprofloxacin Incorporated by Blending or Physisorption

Electrospun fibers are excellent candidates for wound dressings and tissue engineering scaffolds. To actively prevent infection during wound healing, the electrospun fibers can be loaded with antimicrobial agents, such as antibiotics or natural antimicrobials. Different methods have been used to incorporate antimicrobial agents in electrospun fibers during the electrospinning process, including blending, coaxial electrospinning, and emulsion electrospinning, to provide controlled release of the agent. Some evidence suggests that a burst release of antimicrobials through physical adsorption, or physisorption, may offer improved antibacterial properties, but a comparison between physisorbed and blended antimicrobial agents has not been conducted. In this study, the antimicrobial and release properties of poly(lactide-co-glycolide) electrospun fibers containing either blended or physisorbed ciprofloxacin are compared using disks containing similar initial amounts of ciprofloxacin. The results demonstrate that physically adsorbed ciprofloxacin provides more effective antibacterial properties than blended ciprofloxacin up to 48 h against P. aeruginosa PA14, S. aureus, and S. epidermidis regardless of initial loading due to a faster release of the antibiotic in the first 6 h. However, beyond 24 h, blended ciprofloxacin retained the clear zones better than physisorbed ciprofloxacin due to a continuous release. Physisorption offers a simple approach for incorporating antibiotics in electrospun fibers for stronger short-term antibacterial effects and may be applied to scaffolds containing blended antibiotics to sustain antibacterial properties for long-term wound dressings.