Background

Nowadays, the demand for antibacterial fabric and health care has increased; so, finding a method to get antibacterial textile is a challenge. Fibers, especially natural fibers (wool and cotton), provide basic requirements such as moisture and nutrients for bacterial growth and multiplication. This often leads to objectionable odor, dermal infection, product deterioration, and other related diseases[1–4]. A variety of materials like quaternary ammonium salt, metal oxide nanoparticles, and nanocomposites are reported as antibacterial agents[1–3]. Using synthetic non-biodegradable chemical compounds for these approaches cause environmental and health concerns. Although natural dyes are known for a long time for dyeing as well as medicinal applications, the structures and protective properties have been recognized only in the recent past[4, 5]. Many of the plants used for dye extraction are classified as medicinal, and some of these have recently been shown to possess remarkable antimicrobial activity[6]. Several sources of plant dyes rich in naphthoquinons such as lawsone from henna, juglone from walnut, and lapachol from alkanet are reported to exhibit antibacterial and antifungal activities[7–10].

Curcuma longa, also known as ‘turmeric’, is used as a coloring agent, and has medicinal properties. Various sesquiterpenes and curcuminoids have been isolated from the rhizome of 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 1 Antimicrobial evaluation against E. coli in different conditions
Full size table

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
Full size table

As Table 3 shows, the dyed samples with turmeric, walnut shell, and henna in different conditions have good washing fastness.

Table 3 Evaluation of washing fastness of treated samples
Full size table

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.

Figure 1
figure 1

Dyeing profile for different natural dyes.

Full size image

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 bacteria concentration in alkaline and acidic condition. Dyed sample with turmeric under neutral condition did not have good antibacterial activity.

Methods

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.

Figure 2
figure 2

Comparison of bacteria reduction of dyed sample. 1- Turmeric (NaOH/Potassium Bichromate), 2- Walnut Shell (NaOH/Potassium Bichromate), 3- Henna (NaOH/Potassium Bichromate) and 4- Ag Nanoparticles after home laundry 20 times.

Full size image

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.

Antibacterial test

The antimicrobial activity was quantitatively evaluated against Escherichia coli (ATCC 6538), a Gram-negative organism, according to the AATCC 100 test method. The fabric samples with 4.8 ± 0.1 cm in diameter were placed in a 250-ml glass jar with screw cap and absorbed 1.0 ± 0.1 ml of bacterial inoculum. After incubation over contact periods of 24 h, 100 ml of sterilized distilled water was added into the jar and shacked vigorously for 1 min. The solution was then serially diluted to 101, 102, 103, and 104. The diluted solution was plated on a nutrient agar and incubated for 24 h at 37°C ± 2°C. Colonies of bacteria recovered on the agar plate were counted, and the percent reduction of bacteria (R) was calculated by the following equation:

R % = B − A × 100 B ,
(1)

where A is the number of bacterial colonies from treated specimen after inoculation over 24 h of contact period and B is the number of bacterial colonies from untreated control specimen after inoculation at 0 contact time.