Comparison between antibacterial activity of some natural dyes and silver nanoparticles

Curcuma longa rhizome (turmeric), walnut, and henna are medicinal plants which are traditionally used for fiber colorations. In this study, the viscose rayon fabrics were dyed with different mordant at a variety of conditions. The dyed fabric and treated fabric with Ag nanoparticles were evaluated for antibacterial activity against pathogenic strain of Gram-negative (Escherichia coli) bacteria. Durability of antibacterial activity to laundering was also investigated. The results indicated that treated fabrics with these natural dyes had excellent antibacterial activity as well as Ag nanoparticles before and after wash.


A r c h i v e o f S I D
C. longa, attributing to its biological characteristics such as antioxidant, anti-inflammatory, wound healing, anticancer, antiproliferative, antifungal, and antibacterial properties [11,12].
In this study, viscose fabric was dyed with walnut, turmeric, and henna, and its antibacterial properties were those treated with Ag nanoparticles.

Results and discussion
Antimicrobial activity of natural dyes Table 1 shows the antimicrobial activity of turmeric, walnut, and henna in different conditions. The dyed fabric with turmeric powder under alkaline condition created a greater effect in reducing bacteria concentration as compared to that under acidic condition. As results show, the dyed fabrics with these natural dyes show high bacterial reduction activity.  Table 2 shows the reduction of bacterial concentration of Ag nanoparticles. The fabric treated with silver nanoparticles performed very high activity with reduction of bacteria against E. coli. Table 2 Antibacterial activity of Ag nanoparticles against E. coli Sample %R (E.coli) Nanosilver-treated fabric 100 As Table 3 shows, the dyed samples with turmeric, walnut shell, and henna in different conditions have good washing fastness.  Figure 1 shows a summary of the antibacterial activities of the samples dyed with turmeric, henna, and walnut and the sample treated with Ag nanoparticles after 20 washings, respectively. As it is evident, the dyed samples withstand severe laundering which indicate good durability.

Conclusion
Viscose fabric was dyed with three different natural dyes (walnut, turmeric, and henna) under different conditions. The antibacterial activity of dyed samples against E. coli were compared with treated samples containing silver nanoparticles. The results indicated that treated fabrics with these natural dyes had excellent antibacterial activity as well as those treated with Ag nanoparticles before and after wash. The dyed fabric with turmeric powder under alkaline condition created a greater effect in reducing bacteria concentration as compared to that under acidic condition. The dyed fabric with potassium bichromate mordant had good reduction of www.SID.ir

Archive of SID A r c h i v e o f S I D
bacteria concentration in alkaline and acidic condition. Dyed sample with turmeric under neutral condition did not have good antibacterial activity.

Materials
In this study, the viscose rayon fabric, Ag nanoparticles, walnut, turmeric, and henna powders were used throughout experiments. Alum and potassium bichromate were purchased from Merk Co., Ltd (Whitehouse Station, NJ, USA). Silver nanoparticles (average size of <150 nm) were supplied from Sigma Aldrich Co., Ltd (St. Louis, MO, USA).

The method of dyeing
Viscose fabrics were dyed by exhaustion method in different conditions (acidic, alkaline, and neuter) as shown in Figure 2. In the dye preparation, 3 g of turmeric and henna powder were dissolved in 40 ml of distilled water, and temperature was gradually raised to 90°C over 30 min and maintained at 90°C for 5 min. In using walnut shell as the dye, 5 g of walnut were added to 50 ml of distilled water and temperature was maintained at 90°C for 40 min. Viscose fabrics were dyed with 2% (owf) of dye. Alum and potassium bichromate were used as mordant. The material-to-liquor ratio was 1:20 and temperature was raised to 90°C over 30 min and maintained at 90°C for 30 min. Dyed fabric was rinsed with cold water and dried.

Treated fabric with Ag nanoparticles
The fabric was dipped in the 5% Ag colloidal solution; dried at 80°C and cured at 160°C for 4 min.

Wash fastness test
The treated samples were washed according to the ISO 105 C10 (2006) to determine the color change and the antimicrobial effect of fabrics after laundering. A gray scale was selected for evaluating washing fastness.