title: Microwave Accelerated Green Synthesis of Stable Silver Nanoparticles with Eucalyptus globulus Leaf Extract and Their Antibacterial and Antibiofilm Activity on Clinical Isolates.
abstract: A simple and rapid microwave assisted method of green synthesis of silver nanoparticles (AgNPs) was developed using aqueous leaf extract of Eucalyptus globulus(ELE), and their antibacterial and antibiofilm potential investigated. With this aim, the aqueous solutions of ELE and AgNO3(1 mM) were mixed (1:4 v/v), and microwave irradiated at 2450 Mhz, for 30 sec. The instant color change of the ELE-AgNO3 mixture from pale yellow to dark brown indicated ELE-AgNPs synthesis. The intensity of peak at 428 nm in UV-Vis spectra, due to the surface plasmon resonance of AgNPs, varied with the amount of ELE, AgNO3 concentration, pH and time of incubation. The biosynthesized ELE-AgNPs were characterized by UV-visible spectroscopy, XRD, TEM, SEM-EDX, FTIR and TGA analyses. The size of ELE-AgNPs was determined to be in range of 1.9-4.3 nm and 5-25 nm, with and without microwave treatment, respectively. SEM exhibited the capping of AgNPs with the ELE constituents, and validated by FTIR analysis. The FTIR data revealed the presence of plant organic constituents and metabolites bound to ELE-AgNPs, which contributes for their stability. The antimicrobial activity of ELE-AgNPs was assessed by growth and biofilm inhibition of extended spectrum β-lactamase (ESBL) producing Pseudomonas aeruginosa, Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) clinical bacterial isolates. The results demonstrated that S. aureus were more sensitive to ELE-AgNPs than E. coli and P. aeruginosa. MRSA exhibited higher sensitive than MSSA, whereas P. aeruginosa were more sensitive than E. coli to ELE-AgNPs treatment. Also, significant (83 ± 3% and 84 ± 5%) biofilm inhibition was observed in case of S. aureus and P. aeruginosa, respectively. The results elucidated environmentally friendly, economical and quick method for production of colloidal bio-functionalized ELE-AgNPs, for effectual clinical applications, as broad spectrum antibacterial agents and biofilm inhibitors.
authors.affiliation: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India.
authors.forename: Khursheed
authors.initials: K
authors.lastname: Ali
authors.affiliation: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India.
authors.forename: Bilal
authors.initials: B
authors.lastname: Ahmed
authors.affiliation: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India.
authors.forename: Sourabh
authors.initials: S
authors.lastname: Dwivedi
authors.affiliation: Chair for DNA Research, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Quaiser
authors.initials: Q
authors.lastname: Saquib
authors.affiliation: Chair for DNA Research, Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Al-Khedhairy
authors.affiliation: Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India.
authors.forename: Javed
authors.initials: J
authors.lastname: Musarrat
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D005052:Eucalyptus / Q000737:chemistry*; D015870:Gene Expression; D055772:Green Chemistry Technology; D053768:Metal Nanoparticles / Q000737:chemistry*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D008826:Microbial Sensitivity Tests; D008872:Microwaves; D010316:Particle Size; D010936:Plant Extracts / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D012834:Silver / Q000737:chemistry; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D012834:Silver; D001618:beta-Lactamases