Antimicrobial textiles, which involve the application of natural antimicrobial substances to fabrics, have been used since ancient times. Egyptians, for example, used spices and herbal coatings on mummy wraps, while the Chinese used antimicrobial bamboo fibers. Another significant advancement was using antibiotics to protect textiles from decay during World War II. However, concerns about conventional antimicrobial agents’ environmental and health effects have arisen, prompting the search for safer alternatives and the emergence of antimicrobial textiles.
Antimicrobial textiles are in high demand in environments prone to harmful microbes, such as hospitals and areas where controlling the spread of infectious microorganisms is critical. These textiles are classified according to their ability to target bacteria, fungi, or viruses. Antimicrobial textiles are also required in public places such as hotels, restaurants, and trains, where items such as towels, curtains, and carpets can potentially contribute to spreading infections.
The importance of antimicrobial textiles stems from their ability to reduce the presence of microbes on clothing and thus prevent infection transmission. Textile surfaces are modified using various techniques to provide functional properties such as water repellency, flame retardancy, and antibacterial activity. Antimicrobial textiles offer numerous advantages, including antimicrobial winter wear, non-plastic bags, and antimicrobial food packaging.
Antimicrobial textiles are needed in a variety of industries, including apparel (such as caps, jackets, and sportswear), commercial settings (such as carpets, vehicle covers, and military fabrics), healthcare (such as bandages, masks, and lab coats), and households (including bedding, curtains, and towels). Antimicrobial properties should be combined with appealing colors, prints, and designs to increase their appeal and effectiveness.
Active antimicrobial agents
Coatings comprising nanoparticles can be applied to both natural and synthetic textiles. Silver nanoparticles (AgNPs) are known for their potent toxicity against various microbes and their long-lasting durability. AgNPs also exhibit antiviral activity against SARS-CoV-2. Various metal and metal oxide nanoparticles, such as titanium, tin, zinc, gold, and copper, can be used in different textiles. Copper oxide nanoparticles (CuONPs) coated on textile materials demonstrate antimicrobial properties by releasing copper ions, coming into direct contact with bacteria, and generating reactive oxygen species.
The biosynthesis and application of nanostructured inorganic materials, like selenium brooms produced using almond skin extract, possess antimicrobial activity. Sustainable antimicrobial textiles can be developed using natural compounds such as cyclodextrins, lignin, and chitosan. Cyclodextrins, with their hydrophilic outer surface and lipophilic central cavity, are increasingly gaining popularity in the textile industry. Fabrics coated with lignin derived from sugarcane bagasse and fabrics coated with chitosan exhibit antibacterial properties. Chitosan-based silver nanoparticle films display effective antibacterial activity and can be used in food packaging.
Types of Antimicrobial Textile
Antimicrobial textiles can be classified into leaching or non-leaching types and biocidal or biostatic categories based on their treatment and mechanism of action. Non-leaching fabrics preserve the natural bacteria on the skin without adverse effects, while biocidal fabrics are preferred for medical and environmental applications. Fabrics with inherent antimicrobial properties may have a limited spectrum of activity and may require adding antimicrobial agents for broader efficacy. Additives can be incorporated during spinning extrusion or applied through coating or impregnation.
Various methods can be employed to assess the antimicrobial properties of textile samples, such as the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Different nanoparticles exhibit antibacterial activity, including silver, zinc oxide, and mixed silver/zinc oxide nanoparticles. Determining the MIC value is crucial for evaluating the effectiveness and cost-effectiveness of antimicrobial agents used in textile development.
To evaluate antifungal textiles, the disk diffusion and tube dilution methods can be utilized to determine their fungicidal and fungistatic properties. Antimicrobial fabrics with modified silica, guanazole complexes, and cellulose fibers containing fungal-synthesized zinc oxide nanoparticles demonstrate antifungal activity against various pathogens.
To prevent infectious diseases, preventing biofilm formation is essential in antimicrobial textiles. Antimicrobial fabrics have been developed incorporating antibacterial or anti-biofilm nanoparticles, inorganic compounds, polymers, and biological components. Methods such as microscopy to observe biofilm formation and assess biofilm viability are used to evaluate anti-biofilm activity. Fabrics treated with propylene imine dendrimers, gold nanoparticles, or P1000-Acrid dendrimers have shown inhibited biofilm development.
Standard protocols are followed to determine the antiviral properties of textiles. The plaque assay and sandwich test methods are commonly employed. Fabrics coated with sodium pentaborate pentahydrate, triclosan, and Glucapon have demonstrated antiviral activity against adenovirus and poliovirus. Fabrics with immobilized silver nanoparticles and polysaccharide coatings have also exhibited antiviral properties. The COVID-19 pandemic has led to increased research into antiviral textiles, particularly regarding the effectiveness of silver nanoparticles against SARS-CoV-2.
Leaching and Non-Leaching-Type Antimicrobial Textile
Textiles are tested for the leaching of antimicrobial agents to determine if they are leaching or non-leaching types. The diffusion of the active compound into agar during agar well diffusion assays determines leaching potential. Non-leaching textiles retain their activity for longer and are considered safe for direct skin contact. Various treatments, including fluoroquinolone derivatives, isocyanate group-containing quaternary ammonium salts, and quaternary ammonium-modified triethoxysilane coatings, have been developed to create non-leaching antimicrobial textiles.
The choice between leaching and non-leaching fabrics depends on technology availability and production costs. Leaching fabrics tend to be more biocidal, while non-leaching fabrics can be biostatic or biorepellent. Natural, synthetic, and blended fabrics have been used to develop antimicrobial textiles for enhanced efficacy against microorganisms.
Applications and Future Perspectives
Antimicrobial textiles find applications in diverse fields such as apparel, commercial settings, healthcare, and households. In the apparel industry, antimicrobial sportswear, winter wear, and designer undergarments have gained popularity due to their ability to prevent microbial growth and odor. Commercial settings benefit from antimicrobial textiles used in carpets, vehicle coverings, and military fabrics. In healthcare, antimicrobial textiles are utilized for bandages, masks, and lab coats, aiding in infection control. Antimicrobial textiles also enhance household hygiene and safety, including bedding, curtains, and towels.
The future of antimicrobial textiles lies in combining functionality with aesthetics. Developing attractive colors, prints, and designs will further increase the acceptance and adoption of antimicrobial textiles. Additionally, advancements in nanotechnology, biotechnology, and surface modification techniques will contribute to developing more effective and eco-friendly antimicrobial textiles.
Emerging areas such as dermatology, bio-functional textiles, fashion design, and space travel offer exciting opportunities for antimicrobial textiles. The COVID-19 pandemic has accelerated the production of metal nanoparticle-based antiviral textiles. Several brands and companies have introduced antimicrobial fabrics in various products, such as clothing, curtains, medical devices, and home furnishings.
However, challenges remain in optimizing antimicrobial textiles’ efficacy, safety, and sustainability. Continuous research is needed to evaluate long-term antimicrobial effectiveness, potential resistance development, and the impact of leaching antimicrobial agents on the environment. Collaboration between textile manufacturers, scientists, and regulatory bodies is crucial to ensure the development and application of antimicrobial textiles align with industry standards and regulations.
Antimicrobial textiles have a long history and are still evolving in response to increasing demand for safer and more effective antimicrobial solutions. Using nanoparticles, natural compounds, and novel coating techniques has paved the way for broad-spectrum antimicrobial textiles. Antimicrobial textiles, which have applications ranging from healthcare to fashion, have significant potential for improving hygiene, preventing infections, and overall well-being. Future research and development efforts should concentrate on improving antimicrobial textiles’ efficacy, safety, and sustainability to meet the changing needs of various industries and consumers.