Silver Nanoparticles: Biosynthesis, Characterization and Application on Cotton Fabrics

Aim: Silver nanoparticles are applied to textiles for their strong antimicrobial activity against human pathogenic bacteria which attached at clothes; improve the clinical dressing and potential uses in various medical applications. In the present study, the silver nanoparticles were synthesized by Aspergillus terreus A2-2, where the biomass filtrate of this strain was used for biosynthesis of silver nanoparticles (AgNPs). The latter is applied to cotton fabrics through pad-dry technique for rendering textiles antibacterial property toward Gram positive bacteria represented by Staphylococcus aureus ATCC 29213 and Bacillus subtilis NCTC 10400. Gram negative bacteria represented by Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 8739.

Place and Duration of Study: This study was performed in collaboration between Botany & Microbiology Department, Faculty of Science, Al-azhar University and Textile Research Division, National Research Center, Dokki, Cairo, Giza, Egypt, from December 2015 until January 2017.

Materials and Methods: fungal isolate Aspergillus terreus A2-2 was isolated from soil sample collected from Helwan governorate, Egypt and used for extracellular biosynthesis of silver nanoparticles. The fungal isolate was identified by morphological characterization, and molecular identification (ITS). Physical factors such as incubation time, temperature and pH value effect on extracellular silver nanoparticles biosynthesis were assessed. Silver nanoparticles were characterized by UV-vis spectroscopy, TEM, XRD, FTIR, Zeta potential and Particle size analysis and SEM-EDX.

Results: The results depicted that, AgNPs were successfully biosynthesized using A. terreus as indicated from changing the color of medium biomass filtrate from pale yellow to dark brownish yellow. In addition, UV-Vis spectra of the formed AgNPs showed the characteristic surface plasmon resonance (SPR) absorption peak at 400 nm. Further, TEM analysis revealed that the biogenic AgNPs were found to be spherical in shape with size diameter average of 3-27 nm. The particle size of the obtained AgNPs was polydispersed mixture with diameter average of 35nm. Eventually, the treated cotton fabrics with AgNPs exhibited bacterial activity reduction with range of 87% and up to 95%, towards Gram positive bacteria represented by Staphylococcus aureus ATCC 29213 and Bacillus subtilis NCTC 10400, Gram negative bacteria represented by Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 8739.