Sustainable magnetic hydrogels derived from cotton fabric waste as candidates for dual-triggered drug release applications

The growing demand for sustainable and biocompatible materials in biomedical engineering, coupled with the need to reduce environmental impact, motivates the exploration of waste-derived cellulose as a renewable hydrogel precursor. Magnetic hydrogels prepared from recycled cotton fabric waste have been developed and characterized as viable candidates for advanced drug release platforms. While magnetic hydrogels are widely studied, the integration of textile waste as a feedstock for dual-trigger drug-release systems remains largely unexplored, representing the specific novelty of this work. Two crosslinking strategies were employed to obtain the hydrogels: chemical crosslinking using citric acid and physical crosslinking via freeze–thaw cycles, incorporating superparamagnetic Fe₃O₄ nanoparticles anchored onto cellulose microfibers. This combination enables responsiveness to both static and alternating magnetic fields, facilitating drug release via magnetic deformation and hyperthermia. Mechanical testing under uniaxial compression revealed that both types of hydrogels exhibited reproducible elastic responses, with a compressive modulus consistent with mechano-responsive drug-release systems reported in the literature. Independently, magnetic hyperthermia assays under alternating magnetic fields (187 kHz, 11.46 kA/m) demonstrated clinically relevant temperature increases (> 20 °C), suitable for thermally triggered drug release. Together, these results underscore the versatility of cotton-based magnetic hydrogels as dual-trigger platforms capable of supporting both mechanically and thermally controlled drug release, advancing sustainable (waste-valorized) functional biomedical materials.