title: Guazuma ulmifolia bark-synthesized Ag, Au and Ag/Au alloy nanoparticles: Photocatalytic potential, DNA/protein interactions, anticancer activity and toxicity against 14 species of microbial pathogens.
abstract: In the present study, we focused on a quick and green method to fabricate Ag, Au and Ag/Au alloy nanoparticles (NPs) using the bark extract of Guazuma ulmifolia L. Green synthesized metal NPs were characterized using different techniques, including UV-Vis spectroscopy, FT-IR, XRD, AFM and HR-TEM analyses. The production of Ag, Au and Ag/Au alloy NPs was observed monitoring color change from colorless to brown, followed by pink and dark brown, as confirmed by UV-Vis spectroscopy characteristic peaks at 436, 522 and 510nm, respectively. TEM shed light on the spherical shapes of NPs with size ranges of 10-15, 20-25 and 10-20nm. Biosynthesized NPs showed good catalytic activity reducing two organic dyes, 4-nitrophenol (4-NP) and Congo red (CR). UV-vis spectroscopy, fluorescence, circular dichroism spectroscopy and viscosity analyses were used to investigate the NP binding with calf thymus DNA. The binding constant of NPs with DNA calculated in UV-Vis absorption studies were 1.18×104, 1.83×104and 2.91×104M-1, respectively, indicating that NPs were able to bind DNA with variable binding affinity: Ag/Au alloy NPs>Ag NPs>Au NPs. Ag/Au alloy NPs also showed binding activity to bovine serum albumin (BSA) over the other NPs. Ag and Ag/Au alloy NPs exhibited good antimicrobial activity on 14 species of microbial pathogens. In addition, the cytotoxic effects of Ag/Au alloy NPs were studied on human cervical cancer cells (HeLa) using MTT assay. Overall, our work showed the promising potential of bark-synthesized Ag and Ag/Au alloy NPs as cheap sources to develop novel and safer photocatalytic, antimicrobial and anticancer agents.
authors.affiliation: Bio-nanomaterials Lab, Department of Nanoscience and Nanotechnology, Alagappa University, Karaikudi-03, Tamil Nadu, India.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Karthika
authors.affiliation: Department of Botany, Alagappa University, Karaikudi-03, Tamil Nadu, India. Electronic address: ayyakannuarumugam@gmail.com.
authors.forename: Ayyakannu
authors.initials: A
authors.lastname: Arumugam
authors.affiliation: Department of Botany, Bharathiar University, Coimbatore-46, Tamil Nadu, India.
authors.forename: Kasi
authors.initials: K
authors.lastname: Gopinath
authors.affiliation: Bio-nanomaterials Lab, Department of Nanoscience and Nanotechnology, Alagappa University, Karaikudi-03, Tamil Nadu, India.
authors.forename: Periyannan
authors.initials: P
authors.lastname: Kaleeswarran
authors.affiliation: Unit of Vector Control, Phytochemistry and Nanotechnology, Department of Zoology, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.
authors.forename: Marimuthu
authors.initials: M
authors.lastname: Govindarajan
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Naiyf S
authors.initials: NS
authors.lastname: Alharbi
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Shine
authors.initials: S
authors.lastname: Kadaikunnan
authors.affiliation: Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.
authors.forename: Jamal M
authors.initials: JM
authors.lastname: Khaled
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy. Electronic address: benelli.giovanni@gmail.com.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Benelli
mesh_terms: D002384:Catalysis; D004354:Drug Screening Assays, Antitumor; D006046:Gold / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D019660:Malvaceae / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D055668:Photochemical Processes; D024301:Plant Bark / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013057:Spectrum Analysis; D014961:X-Ray Diffraction
chemical_list: D012834:Silver; D006046:Gold
keywords: 4-nitrophenol; Cervical cancer; Congo red; Metal nanoparticles