Magnetizing Cellulose Fibers with CoFe₂O₄ Nanoparticles for Smart Wound Dressing for Healing Monitoring Capability

In an attempt to address issues accompanying the unnecessary change of wound dressings of patients in traditional wound care management, we are developing smart wound dressing material, based on magnetic nanosensors, for wireless monitoring of the wound healing process. The technology is based on magnetizing the cellulose component of the dressing and tuning the resulting magnetic cellulose to respond to temperature changes of the wound. Here, we report the development of the magnetic cellulose through grafting of magnetic CoFe₂O₄ nanoparticles (CoFe₂O₄ NPs) onto cellulose fibers using a layer-by-layer method. Three different methods were used for the synthesis, but the CoFe₂O₄ NPs with superior properties were obtained through hydrothermal autoclaving followed by annealing. They had 98% match to the XRD reference pattern and rod-like shape (agglomerating into nanowires), with diameter between 30 and 50 nm and length ranging from 582 nm to 5.42 μm and magnetization and demagnetization values of 84.5 emu g^-1 and -84.5 emu g^-1, respectively. Upon grafting the CoFe₂O₄ NP onto fibers, the cellulose became magnetic, with magnetization values dependent on the initial concentration of the CoFe₂O₄ NP in the grafting media. Computational investigation revealed that the CoFe₂O₄ NPs are covalently bonded onto the cellulose fiber through the formation of -Co-O-C- bonding. In brief, the current findings advanced the development of a wireless wound-healing monitoring technology based on integration of sensory ferrimagnet CoFe₂O₄ NPs into cellulose fibers of wound dressings.