Development of material with strong antimicrobial activity by high pressure CO2 impregnation of polyamide nanofibers with thymol

This study discusses the potential of high pressure (supercritical and liquid) CO2 impregnation to load electrospun polyamide nanofibers with thymol as an antimicrobial agent. The influence of selected pressures and temperatures on the thymol impregnation yield has been evaluated. High pressure impregnation provided superior thymol impregnation yields (up to ∼60%) on nanofibers compared to conventional immersion methods (∼2%). The presence of thymol in impregnated samples was confirmed by FT-IR analysis. FESEM analysis revealed that impregnation with thymol resulted in a swelling of the nanofibers. The nanofiber morphological changes strongly depended on the thymol impregnation yield. Nanofibers impregnated with thymol using high pressure CO2 ensured excellent antimicrobial activity against Gram-negative bacterium E. coli, Gram-positive bacterium S. aureus and fungus C. albicans. In addition, the Higuchi release model well fitted the thymol release studies.