Polymethacrylate coated electrospun chitosan/PEO nanofibers loaded with thyme essential oil: a newfound potential for antimicrobial food packaging

Development of antimicrobial nanofibers by the electrospinning process is one of the most emerging trends in food bio-packaging systems. In this study, the blend of chitosan (CS) and polyethylene oxide (PEO) was employed to fabricate electrospun nanofibrous mats. Thyme essential oil (TEO) was embedded into the electrospun CS/PEO mats at concentrations of 0.5%, 1%, and 1.5% to create nanofibers with antibacterial properties.  Adding functional groups to the surface of the CS/PEO/TEO electrospun mat was achieved by dip-coating the mat into a poly (MMA-co-MAA) solution with two different compositions to enhance bacteria immobilization. The morphology and diameter of CS/PEO/TEO nanofibers before and after coating were investigated by field emission scanning electron microscopy (FE-SEM). Atomic force microscopy (AFM) and water contact angle (WCA) measurements demonstrated the physical properties of coated and uncoated electrospun mats. Fourier transform infrared spectroscopy (FTIR) was further utilized to reveal the chemical structure of nanofibrous mats. The inhibition zone diameter was employed as an indicator of antibacterial activity through the disk diffusion test. The study results showed that the TEO-loaded nanofibrous mats, fabricated by an electrospinning system and coated by poly (MMA-co-MAA) at a 7:3 ratio of MMA: MAA can effectively inhibit the growth of bacteria. This novel biopolymer-based electrospun mat proved to be a promising candidate for antimicrobial packaging material due to the remarkable properties of biocompatibility, biodegradability, and excellent antibacterial performance.