Synthesis, characterization and antibacterial effect of poly(acrylonitrile/maleic acid)–silver nanocomposite

Inorganic Nanoflowers—Synthetic Strategies and Physicochemical Properties for Biomedical Applications: A Review

Nanoflowers, which are flower-shaped nanomaterials, have attracted significant attention from scientists due to their unique morphologies, facile synthetic methods, and physicochemical properties such as a high surface-to-volume ratio, enhanced charge transfer and carrier immobility, and an increased surface reaction efficiency. Nanoflowers can be synthesized using inorganic or organic materials, or a combination of both (called a hybrid), and are mainly used for biomedical applications. Thus far, researchers have focused on hybrid nanoflowers and only a few studies on inorganic nanoflowers have been reported. For the first time in the literature, we have consolidated all the reports on the biomedical applications of inorganic nanoflowers in this review. Herein, we review some important inorganic nanoflowers, which have applications in antibacterial treatment, wound healing, combinatorial cancer therapy, drug delivery, and biosensors to detect diseased conditions such as diabetes, amyloidosis, and hydrogen peroxide poisoning. In addition, we discuss the recent advances in their biomedical applications and preparation methods. Finally, we provide a perspective on the current trends and potential future directions in nanoflower research. The development of inorganic nanoflowers for biomedical applications has been limited to date. Therefore, a diverse range of nanoflowers comprising inorganic elements and materials with composite structures must be synthesized using ecofriendly synthetic strategies.

Synthesis, characteristics and medical applications of plant nanomaterials

The recent preparations of metal nanoparticles using plant extracts as reducing agents are summarized here. The synthesis and characterization of plant-metal nanomaterials and the progress in antibacterial and anti-inflammatory medical applications are detailed, providing a new vision for plant-based medical applications. The medical application of plant-metal nanoparticles is becoming a research hotspot. Compared with traditional preparation methods, the synthesis of plant-metal nanoparticles is less toxic and more eco-friendly, increasing application potential. Highly efficient plant-metal nanoparticles are usually smaller than 100 nm. This review describes the synthesis, characterization and bioactivities of gold- and silver-plant nanoparticles as examples and clearly explained their antibacterial and anticancer mechanisms. An analysis of actual cases shows that the synthetic method and type of plant extract affect the activities of the products.

Biogenic Synthesis of Silver Nanoparticle from Mushroom Exopolysaccharides and its Potentials in Water Purification

Objective:

This study reports a novel eco-friendly biosynthesis of Silver Nanoparticles (AgNPs) from Exopolysaccharides (EPS) ofLentinus edodesafter an attempt to optimise the production of EPS through mutagenesis. It further describes some potential application of silver nanoparticles in water treatment.

Methods:

A wild strain ofL. edodeswas subjected to UV irradiation, a physical mutagen, at 254 nm. The wild and resultant irradiated strains were then assessed for the production of EPS and subsequent application of the crude EPSs for biosynthesis of AgNPs. The particles were characterised by colour pattern and UV-visible spectroscopy. Based on superior EPS production and nanoparticle attributes, nanoparticles obtained from UV irradiated process were further subjected to Scanning Electron Microscopy (SEM). EPS produced was quantified by the phenol-sulphuric acid method and studied by GC-MS.

Results:

Results obtained for EPS productivity indicated the presence of monomer sugars such as arabinose (50.65%), mannose (19.20%), mannitol (15.58%), fructose (7.96%), trehalose (6.49%), and glucuronic acid, xylose, galactose and glucose with low percentages of ≤ 0.11. EPS productivity of wild and mutant strains was obtained as 1.044 and 2.783 mg/ml, respectively, after 7 days of fermentation. The result of EPS production for UV irradiated strain corresponds to a yield improvement of 2.7 fold of the wild-type. UV Spectroscopy and SEM analysis studies on EPS nanoparticle product of the improved (UV irradiated) strain indicated the formation of AgNPs at the absorption band of 421 nm with a size range of 50-100 nm.

Conclusion:

This study, which aimed at eco-friendly synthesis of myco-nanoparticle has established the novel ability ofL. edodes’polysaccharide in silver nanoparticles biosynthesis. It expounded potential frontiers of silver nanoparticles application in the water industry. To the best of the authors’ knowledge, this result represents the first report on the biosynthesis of AgNPs usingL. edode’sEPS.

Green synthesis of silver nanoparticles using Glaucium corniculatum (L.) Curtis extract and evaluation of its antibacterial activity

The metal nanoparticles, due to interesting features such as electrical, optical, chemical and magnetic properties, have been investigated repeatedly. Also, the mentioned nanoparticles have specific uses in terms of their antibacterial activity. The biosynthesis method is more appropriate than the chemical method for producing the nanoparticles because it does not need any special facilities; it is also economically affordable. In the current study, the silver nanoparticles (AgNPs) were obtained by using a very simple and low-cost method via Glaucium corniculatum (L.) Curtis plant extract. The characteristics of the AgNPs were investigated using techniques including: X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy. The SEM and TEM images showed that the nanoparticles had a spherical shape, and the mean diameter of them was 53.7 and 45 nm, respectively. The results of the disc diffusion test used for measuring the anti-bacterial activity of the synthesised nanoparticles indicated that the formed nanoparticles possessed a suitable anti-bacterial activity.

Green synthesis and characterisation of CuNPs: insights into their potential bioactivity

The current investigation involves the green synthesis of copper nanoparticles (CuNPs) from an aqueous plant extract of Moringa oleifera Lam by two methods: (I) time‐based approach and (II) heat treatment of aqueous solution. Prepared CuNPs were characterised via Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy and transmission EM. The study also reveals the potential bioactivity of the prepared CuNPs. In vitro anti‐microbial efficiency of CuNPs was estimated against bacterial and fungal strains by the agar well diffusion method. Anti‐oxidant capacity of CuNPs was determined using ferric reducing ability of plasma (FRAP), lipid peroxidation (LPO) and peroxidase assays, while the antiplatelet potential was determined by measuring two haemostatic parameters (PT & APTT assay). The minimum inhibitory concentration was observed at 60 µg/ml against Streptomyces griseus and Aspergillus niger when NPs were prepared by method II. CuNPs prepared by the method I showed higher FRAP and LPO activities, while increased POX activity was found in CuNPs prepared by method II. CuNPs prepared using method I also showed better anti‐oxidant and antiplatelet potential. It was observed that M. oleifera ‐derived CuNPs exhibits strong anti‐microbial, anti‐oxidant and APTT potential. This indicates potential utilization of green synthesized NPs for various industrial and therapeutic strategies.

Gundelia tournefortii L.: a natural source for the green synthesis of silver nanoparticles

The present study focused on the synthesis of spherical silver nanoparticles (Ag NPs) using Gundelia tournefortii L. aerial part extract. The plant extract could reduce silver ions into Ag NPs. To identify the compounds responsible for the reduction of silver ions, functional groups present in plant extract were investigated by Fourier transform infrared spectroscopy. Techniques used to characterise synthesised nanoparticles included field emission scanning electron microscopy, X‐ray diffraction and transmission electron microscopy. UV‐visible spectrophotometer showed the absorbance peak in the range of 400–450 nm. The Ag NPs showed antibacterial activities against both gram positive (Staphylococcus aureus and Bacillus Cereus) and gram negative (Salmonella typhimurium and Escherichia coli) microorganisms. The results confirmed that this protocol was simple, rapid, eco‐friendly, low‐priced and non‐toxic; therefore, it could be used as an alternative to conventional physical/chemical methods. Only 5 min were required for the conversion of silver ions into Ag NPs at room temperature, without the involvement of any hazardous chemical.

Synthesis, characterization and antibacterial activity of Ag incorporated ZnO–graphene nanocomposites

One pot low temperature synthesis of silver incorporated ZnO–chemically converted graphene nanocomposites is reported. An optimum of 10% Ag incorporated sample at 6.25 μg ml⁻¹ dose shows an excellent antibacterial activity on E. coli and S. aureus.