Antibacterial Cellulosic Nanocomposites Functionalized with Silver Nanoparticles for Children's Underwear: Synthesis,
Samirah Al Otaibi1, Elham A M Hassanin1, Hassan Ibrahim2
1Department of Fashion and Textile Design, College of Designs and Applied Arts, Taif University, Ta'if, Kingdom of Saudi Arabia.
Abstract:
Introduction/ Objective: Bacterial skin infections are frequent in young children, especially in areas covered by undergarments where moisture and warmth promote microbial growth. Silver nanoparticles (AgNPs), with well-known broad-spectrum antibacterial properties, have been extensively investigated for textile functionalization. This study aimed to synthesize and characterize AgNPs, incorporate them into various cellulosic fabric substrates, and conduct a comprehensive evaluation of their antibacterial performance, physical properties, wash durability, and in vitro biocompatibility using models of adult skin cells for the development and application of AgNP-functionalized cellulosic fabrics in children's underwear.
Methods:
Chemically prepared AgNPs were reduced from silver nitrate (AgNO3) using sodium borohydride as the reducing agent and stabilized with polyvinyl alcohol (PVA). Three types of cellulosic fabrics, 100% cotton woven, cotton/polyester blend (60/40), and cotton nonwoven, were treated with AgNP-PVA suspensions at concentrations of 50, 100, and 150 ppm by the pad-dry-cure technique. UVVis spectroscopy, DLS, TEM, XRD, SEM, and FTIR characterized the nanoparticles and treated fabrics. The antibacterial activity against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) was quantified by agar diffusion and bacterial reduction assays with post-wash evaluation. The physical properties, such as tensile strength, air permeability, water vapour permeability, and whiteness index, were evaluated according to standard methods. Cytotoxicity was evaluated on human dermal fibroblasts (HDF) and spontaneously immortalized keratinocytes (HaCaT) by MTT assay according to the extraction conditions of ISO 10993-12:2012.
Results:
The synthesized AgNPs were mainly spherical (18 ± 4 nm by TEM) with a zeta potential of - 32.5 ± 2.3 mV, indicating a stable colloidal suspension. The inhibition zones for AgNPs in 2% PVA on cotton fabrics were 21.3 ± 0.9 mm (S. aureus) and 18.7 ± 0.8 mm (E. coli), and bacterial reduction was above 99.8%. Antibacterial activity was retained above 90% after 20 washing cycles. There was no significant effect on physical properties (tensile strength decreased by 3-7%; p > 0.05). Cytotoxicity studies revealed that the fabrics treated at 50-100 ppm had cell viability above 85%, which is the noncytotoxicity threshold according to ISO 10993-5. HaCaT viability was reduced to 75.8% at 100% extract concentration, approaching but not exceeding the cytotoxicity threshold at 150 ppm. These data were obtained from adult cell lines; testing in age-appropriate pediatric models is lacking.
Discussion:
The results indicate that AgNP loading, fabric substrate, and PVA-mediated immobilization jointly determine the balance between antibacterial efficacy, wash durability, and biocompatibility. The 100 ppm treatment on cotton offered the most favorable overall balance, while the 150 ppm treatment, despite superior antibacterial performance, approached the cytotoxicity threshold and reduced the whiteness index, indicating a narrower safety margin for pediatric use.
Conclusion:
100 ppm AgNPs in 2% PVA coated on cotton fabric showed the best compromise between antibacterial efficacy, wash durability, physical integrity, and biocompatibility among all the conditions tested. This formulation is a promising candidate for functional textiles for children's underwear, but further investigation is needed for full pediatric safety validation.
