Embedding the Bioactive Agent in Dye Structure for Development of Environmentally Sustainable Bioactive Textiles

The growing demand for durable and environmentally sustainable bioactive textiles has created a need for functionalization strategies that minimize the release of active agents during use and laundering. In this study, a novel chloroxylenol-functionalized vinyl sulfone reactive dye was synthesized through the coupling of chloroxylenol with diazotized para-ester and characterized using FTIR, UV-Vis, ¹H-NMR, and ¹³C-NMR spectroscopy. The synthesized dye was applied to cotton fabric through an exhaust dyeing process, enabling simultaneous coloration and biofunctionalization in a single step. The dye exhibited high substantivity toward cotton, achieving dye exhaustion and fixation values of 95% and 91%, respectively. The dyed fabric demonstrated excellent antibacterial activity against Staphylococcus aureus (99.99%) and Escherichia coli (94%), antiviral activity of 87%, and antifungal activity of 86% before laundering. After 20 laundering cycles, antibacterial activity remained at 96% against S. aureus and 91% against E. coli, while antiviral and antifungal activities remained at 83% and 82%, respectively, confirming the durability of the bioactive functionality. Optical density measurements further verified substantial bacterial growth inhibition, whereas MTT assays using L929 fibroblasts demonstrated acceptable biocompatibility with cell viability exceeding 80% at the highest tested concentration. The dyed fabrics also exhibited excellent ultraviolet protection (UPF 119) with UVA and UVB blocking efficiencies of 99.35% and 98.98%, respectively, together with good colorfastness properties. Furthermore, UV-Vis analysis of the washing liquor indicated negligible dye release under the investigated laundering conditions. These findings demonstrate an effective and sustainable one-step strategy for producing durable multifunctional bioactive textiles while reducing processing steps and minimizing the potential release of active agents during use.