Cotton fabric loaded with ZnO nanoflowers as a photocatalytic reactor with promising antibacterial activity against pathogenic E. coli
Ambreen Ashar, Zeeshan Ahmad Bhutta, Muhammad Shoaib, Nada K. Alharbi, M. Fakhar-e-Alam, M. Atif, Muhammad Fakhar‐e‐Alam Kulyar, Ashar Mahfooz, Prerona Boruah, Mohamed R. Eletmany, Fatimah A. Al‐Saeed, Ahmed Ezzat Ahmed
Abstract
Nanofinishing is the process by which ultrafine dispersion of nanomaterials is applied to a textile for development of functionalities. The utilization of nano metal oxides as antimicrobial agents have shown a substantial antimicrobial property in cotton. In the present study, previously synthesized powder containing ZnO nanoflowers (ZnO NFs) was characterized for morphology, surface composition, roughness and charge using Transmission electron microscopy (TEM), Scanning transmission electron microscopy (STEM), Atomic force microscopy(AFM) and Zeta potential. Optical properties of crystalline ZnO were determined by Photoluminescence (PL), Diffused reflectance Spectroscopy (DRS) and bandgap energy determination. Highly crystalline, ZnO NFs bearing crystal defects and high surface charge were loaded onto the pristine cotton by dip coating method using Triton X-100 as dispersant and iSys MTX fabric binder. The pristine cotton fabric of 125g/m2 was nanofinished by loading 20,42 and 58 µg/cm2 (1-3 dip cycles) ZnO NFs respectively. The loading of ZnO NFs onto the surface of cotton fabric was confirmed by SEM and used for antibacterial activity against E. coli as a photocatalytic reactor. The prepared samples were irradiated to UV lamp of λmax =254 nm (15 min, 30 min, 45 min) and D65 artificial sunlight (60 min, 120 min, 180 min) to investigate their photocatalytic activity against pathogenic E. coli using modified Breed Smear’s method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ZnO [email protected] cotton was determined as 19.53 µg/ml and 39.06 µg/ml respectively after exposure to UV light. After exposure to sunlight MIC and MBC observed were higher i.e. 156.25 µg/ml and 312.5 µg/ml respectively showing lesser activity in sunlight as compared to ionizing UV radiations. To verify the photocatalytic activity, hydroxyl radicals generated by ZnO [email protected] cotton were also determined by time resolved PL on exposure to UV lamp and D65 artificial sunlight. This nanofinished cotton is a promising candidate to be used as a medical textile with high antibacterial activity even after 20 washing cycles with only 5% decrease in efficiency.