Brown cotton fibers self-produce ag nanoparticles for regenerating their antimicrobial surfaces

Authors: Nam, Sunghyun; Selling, Gordon; Hillyer, Matthew; Condon, Brian; RAHMAN, SAIFUR - Texas A&M University; Chang, Sechin

Submitted to: American Chemical Society Applied Nano Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2021
Publication Date: 11/1/2021
Citation: Nam, S., Selling, G.W., Hillyer, M.B., Condon, B.D., Rahman, S., Chang, S. 2021. Brown cotton fibers self-produce ag nanoparticles for regenerating their antimicrobial surfaces. American Chemical Society Applied Nano Materials. 4(12):13112-13122.

Interpretive Summary: The frequent outbreak of new pandemic diseases urges the development of reliable protective textile products. This study demonstrates that permanent antimicrobial textile products can be produced by embedding silver nanoparticles into fibers. The idea was to utilize brown cotton fiber as both reducing and stabilizing agents—allowing its natural component of condensed tannins to reduce silver ions and the swollen fiber structure to stabilize the particle growth. The silver nanoparticles formed within the fiber exhibited excellent leach resistance against continuous launderings. About 85% of the total silver remained in cotton after 50 laundering cycles and inhibited 99.99% Gram-positive and Gram-negative bacteria. The blend of this permanent antimicrobial brown cotton fiber in the fabrication of clothing and textiles such as sportswear, underwear, and hospital and medical textiles (bedsheets, curtains, and gowns) will give protection from infection- and odor-causing bacteria wash after wash.

Technical Abstract: The embedding of functional nanoparticles into fiber is an ideal way to the long-term retention of the functionality. But the nanocomposite formation is a great challenge for cellulosic fibers, which consist of strongly hydrogen-bonded microfibrils. Here we show that naturally colored brown cotton fiber is a nanoreactor to internally synthesize antimicrobial silver nanoparticles (Ag NPs). A simple one-step process of heating brown cotton in an aqueous solution of Ag ions actuates its self-synthesis of Ag NPs without the aid of any external agents—the component of condensed tannins reduces Ag ions, and the swollen microfibrillar structure stabilizes the particle growth. TEM images of the cross-section of the fiber confirm the formation of Ag NPs (8-21 nm in diameter, 12,800 mg/kg) with a unique distribution pattern throughout the entire volume of the fiber. Ag NPs within cotton fiber are immobilized, exhibiting strong leach-resistance against typical textile wet processing and multiple launderings, and regenerate the antimicrobial cotton surface. After 50 laundering cycles, the cotton retains about 85% of the total Ag and continues to inhibit 99.99% of both Gram-positive and Gram-negative bacteria.