Natamycin-loaded electrospun poly(ε-caprolactone) nanofibers as an innovative platform for antifungal applications

This study aimed to develop and characterize poly-ε-caprolactone (PCL) nanofibers containing the natural antifungal natamycin by electrospinning technique using four different formulations. Morphological, structural and thermal properties of PCL nanofibers, with or without natamycin, were investigated by scanning electron microscopy, Fourier-transform and near infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry. Electrospun nanofibers were tested against filamentous fungi and yeasts. SEM images revealed the formation of nanofibers with typical string-like morphology, with mean diameter ranging from 232 to 363 nm. Results from spectroscopy and thermal analyses indicated that no relevant drug-polymer interaction takes place during nanofiber preparation. Natamycin-loaded nanofibers prepared from the formulations NF1 (PLC dissolved in tetrahydrofuran/dimethylformamide) and NF4 (PLC with polyethylene glycol and medium-chain triglycerides dissolved in tetrahydrofuran/chloroform) presented better antifungal activity. A gradual natamycin migration from the PCL nanofibers was observed. The inhibition zones ranged from 4.3 to 25.6 mm, including when fungi were cultivated in skimmed milk agar as a food model system. The antifungal effect of nanofibers was also confirmed in samples of soft cheese. This work provides electrospinning formulations to prepare natamycin-loaded nanofibers as promising platforms to combat filamentous fungi and yeasts.