Green biosynthesis of magnetic iron oxide (Fe 3 O 4 ) nanoparticles using the aqueous extracts of food processing wastes under photo-catalyzed condition and investigation of their antimicrobial and antioxidant activity

Ultrasound Assisted Green Synthesis of Silver and Iron Oxide Nanoparticles Using Fenugreek Seed Extract and Their Enhanced Antibacterial and Antioxidant Activities

This study reports a facile and ecofriendly approach for the ultrasound assisted synthesis of silver and iron oxide nanoparticles and their enhanced antibacterial and antioxidant activities. The fenugreek seed extract was used as reducing, capping, and stabilizing agent in the synthesis of nanoparticles. The transmission electron microscopy results showed that nanoparticles synthesized by ultrasonication have a smaller size (~20 nm) as compared to the nanoparticles fabricated by magnetic stirring (~40 nm). The color change of the solution from milky white to brown suggested the formation of silver nanoparticles which was confirmed by the presence of an absorbance peak at 396 nm. The results of powder X-ray diffraction and energy dispersive X-ray spectroscopy confirmed the crystallinity and elements present in nanoparticles synthesized using fenugreek seed extract. Fourier transform infrared analysis showed that the fenugreek seed phytochemicals were coated on the nanoparticle surface. Thermal gravimetric analysis showed the thermal degradation and stability of nanoparticles. Magnetization study of iron oxide nanoparticles confirmed the superparamagnetic nature. The silver nanoparticles showed antibacterial activities against both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria, while no antibacterial activities were observed for iron oxide nanoparticles. The ultrasound assisted nanoparticles showed higher stability and antibacterial and antioxidant activity compared with the nanoparticles fabricated by magnetic stirring.

Wealth from waste: M. acuminata peel waste-derived magnetic nanoparticles as a solid catalyst for the Henry reaction

Biosynthesis of nanoparticles by exploiting different plant materials has become a matter of great interest in recent years and is considered as a green technology as it does not involve any harmful and toxic chemicals in the synthetic procedure. In this paper, we report a novel one-pot M. acuminata peel ash extract mediated bio-synthesis of basic iron oxide nanoparticles (MAPAE@Fe₃O₄). The nanoparticles were fully characterized by different analytical techniques such as XRF, IR, XRD, XPS, SEM, TEM, VSM and TGA. The synthesized nanoparticles exhibited high basicity due to the presence of metal oxides, primarily basic K₂O in the outer layer of Fe₃O₄ surfaces, and showed good catalytic activity for the synthesis of β-nitroalcohol via the Henry reaction at room temperature under solvent-free conditions. The catalyst was separated from the reaction medium by simply applying an external bar magnet making the process economical and less labor intensive. Furthermore, the catalyst can be reused up to the 4^th cycle without much loss of its activity.

Remote Trice Light, Temperature, and pH-actuation of Switchable Magneto-Plasmonic Nanocarriers for Combinational Photothermal and Controlled/Targeted Chemotherapies

Three magneto-plasmonic nanohybrids were synthesized using Au- and Ag-coated Fe₃O₄ nanoparticles (NPs)-modified dual pH- and temperature-responsive triblock copolymer of poly (butyl methacrylate-co-acrylamide-co-methacrylic acid) to serve as drug carriers with potential of using in both photothermal and controlled/targeted chemotherapies. The internal superparamagnetic core gives the carriers targeted-delivery characteristics, and surface plasmon resonance-based noble metallic Au/Ag shells give them on-demand photothermal and photo-triggering release properties. To investigate the effect of coating method on the targeting property of synthesized carriers, Au NPs were attached to the magnetic core by 2 different direct/indirect procedures and the properties of the synthesized carriers including swelling ratio and thermal and optical sensitivity and switching were comprehensively investigated in 2 different buffer solutions with pH 5.5 and 7.4 at 37°C. Letrozole was used as a model anticancer drug and its loading and release properties were evaluated for the four nanocarriers. The cytotoxicity of drug-free and letrozole-loaded nanocarriers on normal L929 fibroblast and MDAMB 231 breast cancer cell lines was evaluated in absence/presence of laser radiation. The results revealed that the carriers have the potential of serving as switchable trimodal light/temperature/pH-triggered and targeted/controlled drug delivery platforms for chemophotothermal therapy.

Biogenic synthesis of iron oxide nanoparticles using Agrewia optiva and Prunus persica phyto species: Characterization, antibacterial and antioxidant activity

A phytoextract mediated synthesis of iron oxide nanoparticles using Agrewia optiva (Dhaman or Biul) and Prunus persica (Peach) leaf extract as capping and stabilizing agent without using hazardous toxic chemicals via biogenic route has been studied. The biogenic method of synthesis is convenient, rapid, cost effective and ecofriendly. The green synthesized nanoparticles were characterized by Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, Attenuated total reflectance spectroscopy, X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy and dynamic light scattering measurements. The antibacterial study was determined by agar well diffusion method to measure the efficiency of both phyto species extract and its mediated iron oxide nanoparticles against five gram positive bacterial stains such as Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Streptococcus pyrogenes (S. pyrogenes), Corynebacterium diphtheriae (C. diphtheriae) and Corynebacterium xerosis (C. xerosis) and three gram negative bacterial stains such as Escherichia coli (E. coli), Klebsiella pneuomoniae (K. pneuomoniae) and Pseudomonas aeruginosa (P. aeruginosa). The antibiotic Ciprofloxacin and Gentamicin have been used as reference standard drugs for gram positive and gram negative bacterial stains, respectively. The antioxidant activity of the phyto extracts and prepared nanoparticles have been performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay employing l-ascorbic acid as a standard.