Coaxial Fibers Based on Polycaprolactone and Collagen: Effects of Active Component Concentrations (CuO NPs and Aloe Vera Extract) on the Antibacterial Properties of the Material ^†

The main task of modern biomedical engineering is to prevent and control infections during the healing of skin wounds. Conventional antibacterial therapies frequently prove ineffective due to the emergence of antibiotic-resistant bacterial strains and their ability to form biofilms. Consequently, the development of antibacterial non-woven wound dressings that promote tissue regeneration, combat infections, and combine biocompatibility, mechanical strength, and potential for bioactive functionalization is regarded as a promising direction.

The aim of this study is to evaluate the antibacterial activity of coaxial non-woven materials based on polycaprolactone (PCL) and collagen (Col), modified with varying concentrations of aloe vera (AV) extract and copper oxide (CuO) nanoparticles (NPs). The materials, with an average fiber diameter of 110–120 nm, were fabricated using electrospinning. The successful incorporation of AV extract and CuO NPs was confirmed using scanning electron microscopy with energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and contact angle measurements. The antibacterial activity of the resulting materials was assessed by the colony-forming unit counting method. The tested strains included both Gram-positive and Gram-negative bacteria, as well as Candida species.

The resulting coaxial PCL/Col-based materials modified with CuO NPs and AV extract exhibited strong antibacterial properties. The most effective formulation, containing 2 wt.% CuO NPs, achieved complete inhibition of eight Gram-negative, five Gram-positive bacteria, and three fungal strains within the first 6 h of incubation. Materials containing 15% AV extract also showed significant antibacterial activity within 24 h against strains including E. coli ATCC25922, E. coli S176, E. coli ATCC35218, P. aeruginosa S246, S. aureus ATCC29213, and S. aureus ATCC700699. The combined use of CuO NPs and AV extract represents a promising strategy for developing biocompatible materials with prolonged antibacterial activity.