abstractthe objective of this research was to nanoencapsulate ajwain (carum copticum l.) essential oil (eo) in cellulose acetate (ca) using the electrospinning technique and evaluate its antioxidant and antimicrobial activity. the main components of ajwain eo were thymol, p-cymene, and - terpinene. a zeta potential of -40.11, -37.85, -35.50, and -31.74 mv was found for nanofibers of pure ca, ca/eo 1%, 2.5%, and 5%, respectively. according to sem images, ca electrospun nanofiber loaded with different concentrations of ajwain eo had nano-scale size and uniform morphology. the antibacterial activity enhanced with higher concentrations of eo, and it was higher for nanoencapsulated eo at the same concentration. the fibers loaded with eo were effective against the microbial strains according to the following decreasing order: e. coli > s. enteritidis > s. dysenteriae > l. monocytogenes > s. aureus. results of the antioxidant assays showed that the abts and dpph scavenging capacity and reduction potential of fe3+ of free and nanoencapsulated eo were as follows: ca/eo 5% = ca/eo 2.5% > eo 5% > ca/eo 1% > eo 2.5% > eo 1%. antioxidant and antibacterial activities of all eo-loaded ca nanofibers were higher than free eo.keywords: ajwaincellulose acetateelectrospinningessential oilnanoencapsulation disclosure statementthe authors declare that they do not have any conflict of interest.additional informationfundingthis work was supported by a research grant from the amol university of special modern technologies, amol, iran.