β-Cyclodextrin- grafted cotton loaded with limonene: a spectroscopically validated strategy for durable antibacterial textiles

This study presents a novel, sustainable approach to enhance the antibacterial properties and wash durability of
organic cotton through β-Cyclodextrin (β-CD) and monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) grafting fol-
lowed by limonene incorporation. Using citric acid as a cross linker and eco-friendly enzymatic bio polishing
conditions, β-CD was effectively anchored onto cotton fibers, facilitating the encapsulation of limonene, a
naturally derived antimicrobial terpene. SEM surface morphology indicated consistent grafting of β-CD/MCT-
β-CD on cotton without fiber damage. Fluorescence spectroscopy confirmed effective incorporation of limonene
within the cyclodextrin cavities. Spectroscopic techniques such as UV–Visible, FTIR, XRD and thermogravimetric
analysis (TGA) confirmed the successful grating and structural integrity of the modified textiles. The experi-
mental data was analyzed using pseudo-first order and second order kinetic models. The pseudo-second order
provided the best match for the kinetic investigations, indicating that the chemisorption process limits the
adsorption of Maxilon Blue GRL (MB) and Direct Yellow 12 (DY 12). HPLC Measurements demonstrated that
grafted and bio-polished textiles exhibited significantly higher limonene loading and retention compared to their
ungrafted counter parts. Antibacterial tests against Escherichia coli and Staphylococcus aureus showed significant
and long-lasting inhibition, notably in biopolished β-CD and MCT-β-CD grafted samples, even after 10 wash
cycles. Negative controls (untreated, biopolished-only and cyclodextrin-grafted textiles without limonene)
showed no inhibition, indicating that limonene release is responsible for long term action. All experiments were
done in triplicate (n = 3) and statistically analyzed using mean ± SD. The work reveals that cyclodextrin-based
inclusion complexes function as controlled- release reservoirs for limonene indicating a possible pathway for
producing high-performance, long lasting antibacterial textiles utilizing ecologically friendly approaches.