8:00 PM - SB05.03.04
Late News: (Garcia High School Student) Repurposing Waste Fabric by Synthesizing Silver Nanoparticles on Deweaved Cotton Fibers
Jacob Zerykier3,Elizabeth Zhang1,Ivan Yuan2,Ayush Agrawal4,Tianyu Dong5,Guanchen Zhu6,Haojun Xu7,Michael Cuiffo8,Stephen Walker8,Miriam Rafailovich8
Phillips Academy1,Shanghai High School International Division2,Rambam Mesivta-Maimonides High School3,Canyon Crest Academy4,Northview High School5,Experimental High School Attached to Beijing Normal University6,The Madeira School7,Stony Brook University, The State University of New York8
Silver nanoparticles (Ag NPs) have well-studied antimicrobial properties effective against many types of bacteria and fungi. Fine Ag NPs have also demonstrated antiviral activity against H1N1 (influenza), SARS-CoV-2, and other viruses.[1,2] The antimicrobial properties of Ag NPs are due to the release of silver ions that inhibit respiratory enzymes of bacteria and fungi. In its main antiviral mechanism, Ag NPs bind to and inactivate membrane proteins, thereby preventing the virus from entering the host cell. Applications of Ag NPs in textiles have gained worldwide attention due to the importance of antimicrobial textiles for wound dressings, medical equipment and staff uniforms, bedsheets, and others. Because textiles serve as a medium for microbe growth and cross-contamination, there is a growing demand for antimicrobial textiles. To reduce waste, especially since the textile industry produces over 10 million tons of waste cotton cloth globally each year, this study seeks to synthesize Ag NPs on discarded cotton muslin tailoring cloth. Cotton fabric can be deweaved into cellulose fibers, which act as a stabilizing agent on which silver nanoparticles can be synthesized through the reduction of silver nitrate with trace amounts of sodium borohydride.
Fabric was deweaved by stirring in a 3:1 by volume ratio solution of 0.5 M citric acid and 0.5 M sodium nitrate at 50 °C and 600 rpm for 15 minutes. After drying, the fibers were used for the synthesis of silver nanoparticles in two ways. Both samples were treated with a solution of 20 mL silver nitrate (0.01 M) and 2-5 drops of sodium borohydride (0.01 M) until a color change was observed. The first sample was placed for 20 minutes at room temperature, while the second sample was ultrasonicated for 20 minutes at 40 °C. Both samples were then air-dried. The solution used in the synthesis process, which contained silver nitrate, sodium borohydride, and silver nanoparticles, was then analyzed using UV-Vis spectrometry. Results showed a peak at 325 nm, which is characteristic of silver nanoparticles. The samples were then observed with SEM to visualize the size and features of the nanoparticles, and EDX was simultaneously performed to verify the existence of silver. The fibers heated in the ultrasonicator showed a higher silver signal in EDX than the non-heated samples, and the silver coating was present on more parts of the fibers in the ultrasonicated sample. The size of the nanoparticles was below the resolution of the SEM. X-ray photoelectron spectroscopy showed that the silver in the nanoparticles existed in both elemental and oxidized forms, both of which are antimicrobial.
We then performed an antibacterial test using S. aureus and E. coli. Deweaved fibers without Ag NPs did not exhibit any antibacterial properties, while both species of bacteria showed zones of exclusion when the Ag NP-containing fibers were used. The zone of exclusion was larger in the culture of S. aureus, suggesting that silver nanoparticles may be more effective against Gram-positive bacteria. Experiments are underway in order to determine the antiviral properties of the silver coating against H1N1 influenza. Hence, this technique has the potential to produce antiviral and antibacterial fibers that can be incorporated into textiles.
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