Investigation of Antimicrobial Activity of DBD Air Plasma-Treated Banana Fabric Coated with Natural Leaf Extracts

This paper focuses on the investigation of the antimicrobial activity of banana fabric treated with dielectric barrier discharge (DBD) plasma. The fabric was exposed to air plasma for varying treatment times of 1-5 min followed by coating with green tea (Camellia sinensis) and tulsi (Ocimum sanctum) leaf extracts at five different concentrations. The treated fabric was evaluated in terms of surface wettability by a range of tests like wet-out time analysis, hydrophilicity test, and contact angle measurements. The functional groups formed on the treated fabric were analyzed by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. The surface morphology was studied using atomic force microscopy (AFM) and scanning electron microscopy (SEM), and the surface chemistry was studied using X-ray photoelectron spectroscopy (XPS). The FTIR and XPS analysis results indicate that the plasma-treated fabric was found to have a higher concentration of polar groups (-COOH, -OH, -C=O) that has improved surface hydrophilicity and functionality. The antimicrobial activity of the treated fabric surface was determined both qualitatively and quantitatively by the agar plate method and modified Hoenstein test, against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. An improvement in the antimicrobial property was observed in plasma-treated banana fabric coated with natural extracts even after four washing cycles. This study suggests that air DBD plasma treatment followed by the absorption of tea/tulsi leaf extracts can serve as a better tool for developing natural antimicrobial textiles, which could serve the purpose in medical and healthcare sectors concerning recent times. It has eventually led to better absorption of plant extracts, thereby increasing their antimicrobial activity.