Scientific African (Nov 2023)
Antibacterial durability of L-methionine modified cotton fabrics functionalized with ZnO nanoparticles
Abstract
Cotton fabric based textiles utilizing metal oxide nanoparticles (NPs), offer potential options for reducing spreading of infection by bacteria due to their excellent antimicrobial properties, which depend on the nanoparticle's structure and morphology, as well as the fiber functionalization process. In this work, a simple padding and rolling technique for preparing antibacterial cotton fabrics by functionalizing their surface with nanostructured ZnO is demonstrated. L-methionine amino acid is utilized as a binding reagent due to its low toxicity to mammalian cells, biocompatibility with living tissues, and the presence of amine and carboxylic groups, which enhance its coordination capacity to improve ZnO adhesion. Zn(NO3)2·3H2O was precipitated as Zn(OH)2(s) using an alkali mixture of (NaOH+NaBH4), which was then converted into ZnO NPs up on heat treatment on the surface of modified cotton (LCt). Fourier transform infrared spectroscopy (ATR-FTIR) was utilized to confirm the chemical alteration of the fabrics by L-methionine. X-ray diffraction (XRD) investigations confirmed the crystalline structure, purity, and average crystallite size of the ZnO NPs (15.72 nm). X-ray photoelectron spectroscopy (XPS) tests revealed that the NPs were successfully coordinately bonded to the textiles. HR-SEM and energy-dispersive X-ray (EDS) mapping demonstrated that NPs were well-covered on the fabric fibers. The thermal degradation behavior of the modified and functionalized cotton was examined by thermal gravimetric analysis (TGA). The functionalized fabric shown outstanding antibacterial activity against gram-negative bacteria, E. coli and P. aeruginosa, as well as gram-positive bacteria S. aurous and S. pyogenes, with washing durability of up 50 wash cycles. After 50 wash cycles, approximately 88 % of the Zn was retained. This indicated a strong bond between the fabrics. Furthermore, the change has little effect on cotton qualities such as vapor permeability, water absorption, and water transport.
