modification of medical cotton gauze with copper-based metal-organic framework (cu-mof) with antimicrobial activity for wound dressing applications

A wound is defined as a lesion or fracture on the surface of the skin caused by physical or heat damage. wound dressing plays an important role in the wound-healing process. the basic needs of wound dressing are inhibition of microbial and enzymatic activity under the wound bed, low adhesion, and promotion of the wound healing process in a moist environment. in this work, a medical cotton gauze was modified through the in-situ growth of a copper-based metal-organic framework (cu-mof). it is hypothesized that the highly porous structure, large specific surface area, biocompatibility, and suitable biodegradability of cu-mof, as well as the biodegradability, biocompatibility, non-toxic nature, and antibacterial properties of chitosan, can be combined to prepare highly efficient medical cotton gauze for wound dressing applications. the successful modification of cotton gauze with chitosan and cu-mof was confirmed by fourier transform infrared spectroscopy (ftir), scanning electron microscopy (sem), and energy dispersive x-ray spectroscopy (eds). it is shown that the modification of cotton gauze with cu-mof enhanced its hydrophobicity with a water contact angle (ca) of 98.5° to resist bacterial adhesion. these results show that the more hydrophobic the cotton gauze, the higher the bacterial anti-adhesion rate can be achieved. the exceptional water-repellency of a hydrophobic cu-mof/gauze with low surface energy makes it particularly effective in preventing bacterial adhesion and infiltration into the fiber interior of a cotton gauze. this is due to the ability of the surface to resist wetting by bacterial suspensions in aqueous environments, thereby impeding their attachment to the cotton gauze surface. moreover, the antibacterial activity of the modified cotton gauze was evaluated against escherichia coli and staphylococcus aureus. the cu-mof/gauze showed excellent antibacterial activity and inhibited the growth of both gram-positive and gram-negative bacteria. the major contribution of cu-mof nanocrystals and chitosan to kill bacteria is benefiting from their inherent antibacterial property. the positively charged cu2+ ions and organic ligand are responsible for antibacterial activity by destroying the microbial membrane. the antibacterial activity of modified cotton gauze benefits from the interaction of protonated amino groups (nh3+) of chitosan with the negatively charged cell membrane of bacteria as well as the presence of cu2+ ions in the structure of cu-mofs. the antibacterial activity was also more effective against s. aureus than e. coli, mainly due to obvious structural differences in the cell wall between gram-positive and gram-negative bacteria. these results suggest that the cu-mof/gauze could be used in the biomedical area, particularly as antimicrobial wound dressings.