Green synthesis and characterization of silver nanoparticles using alcoholic flower extract of Nyctanthes arbortristis and in vitro investigation of their antibacterial and cytotoxic activities

Green synthesized Zn-based mono and bi-metallic nanoparticles for improved micronutrient delivery: A futuristic study in hydroponic crop culture system

Hydroponic farming is gaining importance due to the rapid expansion of cities worldwide. However, the significance of nano-enabled nutrient delivery in hydroponic crop culture is still poorly understood. Therefore, ZnO monometallic and Zn-Cu bimetallic nanoparticles (MNP and BNP) were innovatively synthesized through green routes using alcoholic leaf extract (ALE) 1-10 % (w/v) of Chrysalidocarpus lutescens due to its enriched phytochemical profile, prolific radical scavenging efficiency, and reasonably high IC50 values. The structural uniformity and batch-wise yield of MNP and BNP were optimized following response surface methodology. The uniqueness of C. lutescens-derived phytochemicals facilitated the production of anisotropic and crystalline MNP and BNP. It was revealed that structural uniformity and yields were most significant at pH 9 with 3 % ALE for both MNP (Yield/batch -20.54 ± 0.15 g) and BNP (Yield/batch - 18.37 ± 0.30 g). Both nanoparticles were hexagonal 30-85 nm nanocrystals, stable at alkaline pH (∼9) with uniform pore volume, surface area, and surface charge. The hydroponic compatibility of the MNP and BNP were compared with non-nanoscale Zn and Cu by cultivating Cicer arietinum with different doses of MNP, BNP, and other treatments. Among all doses, 250 and 500 mg L-1 doses of MNP and BNP significantly augmented C. arietinum germination by ∼40-45 % and plumule growth by ∼18-22 % and enhanced chlorophyll stability while reducing oxidative stress in the seedlings. The MNP and BNP were ecologically safe for microorganisms (Rhizobium sp. and Salmonella typhi) and were viable within 250 mg L-1 to 2000 mg L-1 of MNP and BNP doses. Overall, the study reveals that the green synthetic routes using C. lutescens phytoextract led to significant yield of productive, biocompatible, and organically rich Zn and Cu-based MNP and BNP that can be easily pursued and sustainably applied in hydroponics or other agriculture platforms.

Potentials of roots, stems, leaves, flowers, fruits, and seeds extract for the synthesis of silver nanoparticles

Silver nanoparticles (AgNPs) have gained significant attention in various applications due to their unique properties that differ from bulk or macro-sized counterparts. In the advancement of nanotechnology, a reliable, non-toxic, and eco-friendly green synthesis has widely been developed as an alternative method for the production of AgNPs, overcoming limitations associated with the traditional physical and chemical methods. Green synthesis of AgNPs involves the utilization of biological sources including plant extracts with silver salt as the precursor. The potential of phytochemicals in plant extracts serves as a reducing/capping and stabilizing agent to aid in the bio-reduction of Ag+ ions into a stable nanoform, Ag0. This review provides insights into the potentials of various plant parts like root, stem, leaf, flower, fruit, and seed extracts that have been extensively reported for the synthesis of AgNPs.

Management of Tomato Bacterial Canker Disease by the Green Fabricated Silver Nanoparticles

Bacterial canker disease caused by Clavibacter michiganensis is a substantial threat to the cultivation of tomatoes, leading to considerable economic losses and global food insecurity. Infection is characterized by white raised lesions on leaves, stem, and fruits with yellow to tan patches between veins, and marginal necrosis. Several agrochemical substances have been reported in previous studies to manage this disease but these were not ecofriendly. Thus present study was designed to control the bacterial canker disease in tomato using green fabricated silver nanoparticles (AgNps). Nanosilver particles (AgNPs) were synthesized utilizing Moringa oleifera leaf extract as a reducing and stabilizing agent. Synthesized AgNPs were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and Fourier transform infrared spectrometry (FTIR). FTIR showed presence of bioactive compounds in green fabricated AgNPs and UV-visible spectroscopy confirmed the surface plasmon resonance (SPR) band in the range of 350 nm to 355 nm. SEM showed the rectangular segments fused together, and XRD confirmed the crystalline nature of the synthesized AgNPs. The presence of metallic silver ions was confirmed by an EDX detector. Different concentrations (10, 20, 30, and 40 ppm) of the green fabricated AgNPs were exogenously applied on tomato before applying an inoculum of Clavibacter michigensis to record the bacterial canker disease incidence at different day intervals. The optimal concentration of AgNPs was found to be 30 µg/mg that exhibited the most favorable impact on morphological (shoot length, root length, plant fresh and dry weights, root fresh and dry weights) and physiological parameters (chlorophyll contents, membrane stability index, and relative water content) as well as biochemical parameters (proline, total soluble sugar and catalase activity). These findings indicated a noteworthy reduction in biotic stress through the increase of both enzymatic and non-enzymatic activities by the green fabricated AgNPs. This study marks a first biocompatible approach in assessing the potential of green fabricated AgNPs in enhancing the well-being of tomato plants that affected with bacterial canker and establishing an effective management strategy against Clavibacter michiganensis. This is the first study suggests that low concentration of green fabricated nanosilvers (AgNPs) from leaf extract of Moringa oleifera against Clavibacter michiganensis is a promisingly efficient and eco-friendly alternative approach for management of bacterial canker disease in tomato crop.

Evaluation of Lippia scaberrima Sond. and Aspalathus linearis (Burm.f.) R. Dahlgren extracts on human CYP enzymes and gold nanoparticle synthesis: implications for drug metabolism and cytotoxicity

BACKGROUND

Metabolism is an important component of the kinetic characteristics of herbal constituents, and it often determines the internal dose and concentration of these effective constituents at the target site. The metabolic profile of plant extracts and pure compounds need to be determined for any possible herb-drug metabolic interactions that might occur.

METHODS

Various concentrations of the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with fermented and unfermented Aspalathus linearis extract were used to determine the inhibitory potential on placental, microsomal and recombinant human hepatic Cytochrome P450 enzymes. Furthermore, the study investigated the synthesis and characterization of gold nanoparticles from the ethanolic extract of Lippia scaberrima as a lead sample. Confirmation and characterization of the synthesized gold nanoparticles were conducted through various methods. Additionally, the cytotoxic properties of the ethanolic extract of Lippia scaberrima were compared with the gold nanoparticles synthesized from Lippia scaberrima using gum arabic as a capping agent.

RESULTS

All the samples showed varying levels of CYP inhibition. The most potent inhibition took place for CYP2C19 and CYP1B1 with 50% inhibitory concentration (IC50) values of less than 0.05 µg/L for the essential oil tested and IC50-values between 0.05 µg/L-1 µg/L for all the other combinations and extracts tested, respectively. For both CYP1A2 and CYP2D6 the IC50-values for the essential oil, the extracts and combinations were found in the range of 1 - 10 µg/L. The majority of the IC50 values found were higher than 10 µg/L and, therefore, were found to have no inhibition against the CYP enzymes tested.

CONCLUSION

Therefore, the essential oil of Lippia scaberrima, the ethanolic extract of Lippia scaberrima alone and their combinations with Aspalathus linearis do not possess any clinically significant CYP interaction potential and may be further investigated for their adjuvant potential for use in the tuberculosis treatment regimen. Furthermore, it was shown that the cytotoxic potential of the Lippia scaberrima gold nanoparticles was reduced by twofold when compared to the ethanolic extract of Lippia scaberrima.

Long-Lasting Silver Nanoparticles Synthesized with Tagetes erecta and Their Antibacterial Activity against Erwinia amylovora, a Serious Rosaceous Pathogen

A rapid, eco-friendly, and simple method for the synthesis of long-lasting (2 years) silver nanoparticles (AgNPs) is reported using aqueous leaf and petal extracts of Tagetes erecta L. The particles were characterized using UV-Visible spectrophotometry and the analytical and crystallographic techniques of transmission electron microscopy (TEM). The longevity of the AgNPs was studied using UV-Vis and high-resolution TEM. The antibacterial activity of the particles against Erwinia amylovora was evaluated using the Kirby-Bauer disk diffusion method. The results were analyzed using ANOVA and Tukey's test (p ≤ 0.05). Both the leaf and petal extracts produced AgNPs, but the leaf extract (1 mL) was long-lasting and quasi-spherical (17.64 ± 8.87 nm), with an absorbance of UV-Vis λmax 433 and a crystalline structure (fcc, 111). Phenols, flavonoids, tannins, and terpenoids which are associated with -OH, C=O, and C=C were identified in the extracts and could act as reducing and stabilizing agents. The best antibacterial activity was obtained with a nanoparticle concentration of 50 mg AgNPs L-1. The main contribution of the present research is to present a sustainable method for producing nanoparticles which are stable for 2 years and with antibacterial activity against E. amylovora, one of most threatening pathogens to pear and apple productions.

Anti-cancer Application of Nat-ZnFe2O4 Nanoparticles on 2D Tumor Models

Metal/Metal Oxide nanoparticles (M/MO NPs) exhibit potential biomedical applications due to their tunable physicochemical properties. Recently, the biogenic synthesis of M/MO NPs has gained massive attention due to their economical and eco-friendly nature. In the present study, Nyctanthes arbor-tristis (Nat) flower extract-derived Zinc Ferrite NPs (Nat-ZnFe2O4 NPs) were synthesized and physicochemically characterized by FTIR, XRD, FE-SEM, DLS, and other instruments to study their crystallinity, size, shape, net charge, presence of phytocompounds on NP's surface and several other features. The average particle size of Nat-ZnFe2O4 NPs was approx. 25.87 ± 5.67 nm. XRD results showed the crystalline nature of Nat-ZnFe2O4 NPs. The net surface charge on NPs was -13.28 ± 7.18 mV. When tested on mouse fibroblasts and human RBCs, these NPs were biocompatible and hemocompatible. Later, these Nat-ZnFe2O4 NPs exhibited potent anti-neoplastic activity against pancreatic, lung, and cervical cancer cells. In addition, NPs induced apoptosis in tested cancer cells through ROS generation. These in vitro studies confirmed that Nat-ZnFe2O4 NPs could be used for cancer therapy. Moreover, further studies are recommended on ex vivo platforms for future clinical applications.

Plant-mediated synthesis of silver nanoparticles: unlocking their pharmacological potential-a comprehensive review

In recent times, nanoparticles have experienced a significant upsurge in popularity, primarily owing to their minute size and their remarkable ability to modify physical, chemical, and biological properties. This burgeoning interest can be attributed to the expanding array of biomedical applications where nanoparticles find utility. These nanoparticles, typically ranging in size from 10 to 100 nm, exhibit diverse shapes, such as spherical, discoidal, and cylindrical configurations. These variations are not solely influenced by the manufacturing processes but are also intricately linked to interactions with surrounding stabilizing agents and initiators. Nanoparticles can be synthesized through physical or chemical methods, yet the biological approach emerges as the most sustainable and eco-friendly alternative among the three. Among the various nanoparticle types, silver nanoparticles have emerged as the most encountered and widely utilized due to their exceptional properties. What makes the synthesis of silver nanoparticles even more appealing is the application of plant-derived sources as reducing agents. This approach not only proves to be cost-effective but also significantly reduces the synthesis time. Notably, silver nanoparticles produced through plant-mediated processes have garnered considerable attention in recent years due to their notable medicinal capabilities. This comprehensive review primarily delves into the diverse medicinal attributes of silver nanoparticles synthesized using plant-mediated techniques. Encompassing antimicrobial properties, cytotoxicity, wound healing, larvicidal effects, anti-angiogenesis activity, antioxidant potential, and antiplasmodial activity, the paper extensively covers these multifaceted roles. Additionally, an endeavor is made to provide an elucidated summary of the operational mechanisms underlying the pharmacological actions of silver nanoparticles.

Plumeria alba flower extract-mediated synthesis of recyclable chitosan-coated cadmium nanoparticles for pest control and dye degradation

In the current scenario, many synthetic chemicals have used long-term to control pests and mosquitoes, leading to the resistance of strains and toxicity effect on human beings. To overcome the adverse problem in recent advances, the scientific community is looking into nanofabricated pesticides and mosquitoes. This study aims to synthesize the recyclable chitosan-coated cadmium nanoparticles (Ch-CdNps) using Plumeria alba flower extract, which was further applied for insecticidal and mosquitocidal activities. The synthesized Ch-CdNps were confirmed by UV spectroscopy and FTIR analysis. The XRD, TEM, and DLS results confirmed the crystallinity with a spherical shape at 80-100 nm. The insecticidal activity proves that Ch-CdNps inhibited Helicoverpa armigera and Spodoptera litura at 100 ppm. In mosquitocidal, LC50 values of larvicidal of 1st instar were 4.116, 4.33, and 4.564 µg/mL, and the remaining three stages of instars, pupicidal, adulticidal, longevity, fecundity, and ovicidal assays inhibit the Anopheles stephensi followed by Aedes aegypti and Culex quinquefasciatus. Further, the first-order kinetics of photocatalytic degradation of methylene blue and methyl orange was confirmed. Based on the obtained results, Ch-CdNps can inhibit the pest, mosquitoes, and photocatalytic degradation.

Synthesis and investigation on synergetic effect of activated carbon loaded silver nanoparticles with enhanced photocatalytic and antibacterial activities

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants.

Deploying a Novel Approach to Prepare Silver Nanoparticle Bellamya bengalensis Extract Conjugate Coating on Orthopedic Implant Biomaterial Discs to Prevent Potential Biofilm Formation

This study is based on the premise of investigating antibacterial activity through a novel conjugate of silver nanoparticles (AgNPs) and antimicrobial peptides (AMPs) in line with a green synthesis approach by developing antimicrobial-coated implants to prevent bacterial resistance. The AMPs were obtained from Bellamya Bengalensis (BB), a freshwater snail, to prepare the nanocomposite conjugate, e.g., AgNPs@BB extract, by making use of UV-Visible spectroscopy. The antimicrobial assessment of AgNPs@BB extract conjugate was performed using the Resazurin Microtiter Assay Method (REMA), followed by the use of three biocompatible implant materials (titanium alloys, Ti 6AL-4V stainless steel 316L, and polyethylene). Finally, the coating was analyzed under confocal microscopy. The results revealed a significant reduction of biofilm formation on the surfaces of implants coated with conjugate (AgNPs@BB extract) in comparison to uncoated implants. For the MTT assay, no significant changes were recorded for the cells grown on the AgNPs/AMP++ sample in high concentrations. Staphylococcus epidermidis, however, showed more prominent growth on all implants in comparison to Staphylococcus aureus. It is evident from the results that Staphylococcus epidermidis is more susceptible to AgNPs@BB extract, while the minimum inhibitory concentration (MIC) value of AgNPs@BB extract conjugates and biosynthesized AgNPs was also on the higher side. This study indicates that AgNPs@BB extract carries antibacterial activity, and concludes that an excessive concentration of AgNPs@BB extract may affect the improved biocompatibility. This study recommends using robust, retentive, and antimicrobial coatings of AgNPs@BB extract for implantable biocompatible materials in accordance with the novel strategy of biomaterial applications.

Biosynthesis, characterization, and investigation of antimicrobial and cytotoxic activities of silver nanoparticles using Solanum tuberosum peel aqueous extract

Metallic nanoparticle biosynthesis is thought to offer opportunities for a wide range of biological uses. The green process of turning biological waste into utilizable products gaining attention due to its economical and eco-friendly approach in recent years. This study reported the ability of Solanum tuberosum (ST) peel extract to the green synthesis of non-toxic, stable, small-sized silver nanoparticles without any toxic reducing agent utilizing the phytochemical components present in its structure. UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, flourier scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and energy dispersive analysis X-ray confirmed the biosynthesis and characterization of silver nanoparticles. Also, dynamic light scattering and thermogravimetric analyses showed stable synthesized nanoparticles. The antibacterial activity of the biosynthesized silver nanoparticles was evaluated against four different bacterial strains, Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) Bacillus subtilis (B. subtilis), and a yeast, Candida albicans (C. albicans) using the minimum inhibitory concentration technique. The cytotoxic activities were determined against Human dermal fibroblast (HDF), glioblastoma (U118), colorectal adenocarcinoma (CaCo-2), and human ovarian (Skov-3) cell lines cancer cells using MTT test. The nanoparticle capping agents that could be involved in the reduction of silver ions to Ag NPs and their stabilization was identified using FTIR. Nanoparticles were spherical in shape and had a size ranging from 3.91 to 27.07 nm, showed crystalline nature, good stability (-31.3 mV), and the presence of capping agents. ST-Ag NPs significantly decreased the growth of bacterial strains after treatment. The in vitro analysis showed that the ST-Ag NPs demonstrated dose-dependent cytotoxicity against cell lines. Based on the data, it is feasible to infer that biogenic Ag NPs were capped with functional groups and demonstrated considerable potential as antibacterial and anticancer agents for biomedical and industrial applications.

Antifungal Activity of Juglans-regia-Mediated Silver Nanoparticles (AgNPs) against Aspergillus-ochraceus-Induced Toxicity in In Vitro and In Vivo Settings

Aflatoxins produced by some species of Aspergillus are considered secondary toxic fungal by-products in feeds and food. Over the past few decades, many experts have focused on preventing the production of aflatoxins by Aspergillus ochraceus and also reducing its toxicity. Applications of various nanomaterials in preventing the production of these toxic aflatoxins have received a lot of attention recently. The purpose of this study was to ascertain the protective impact of Juglans-regia-mediated silver nanoparticles (AgNPs) against Aspergillus-ochraceus-induced toxicity by exhibiting strong antifungal activity in in vitro (wheat seeds) and in vivo (Albino rats) settings. For the synthesis of AgNPs, the leaf extract of J. regia enriched with high phenolic (72.68 ± 2.13 mg GAE/g DW) and flavonoid (18.89 ± 0.31 mg QE/g DW) contents was used. Synthesized AgNPs were characterized by various techniques, including TEM, EDX, FT-IR, and XRD, which revealed that the particles were spherical in shape with no agglomeration and fine particle size in the range of 16-20 nm. In vitro antifungal activity of AgNPs was tested on wheat grains by inhibiting the production of toxic aflatoxins by A. ochraceus. According to the results obtained from High-Performance Liquid Chromatography (HPLC) and Thin-Layer Chromatography (TLC) analyses, there was a correlation between the concentration of AgNPs and a decrease in the production of aflatoxin G1, B1, and G2. For in vivo antifungal activity, Albino rats were administrated with different doses of AgNPs in five groups. The results indicated that the feed concentration of 50 µg/kg feed of AgNPs was more effective in improving the disturbed levels of different functional parameters of the liver (alanine transaminase (ALT): 54.0 ± 3.79 U/L and aspartate transaminase (AST): 206 ± 8.69 U/L) and kidney (creatinine 0.49 ± 0.020 U/L and BUN 35.7 ± 1.45 U/L), as well as the lipid profile (LDL 22.3 ± 1.45 U/L and HDL 26.3 ± 2.33 U/L). Furthermore, the histopathological analysis of various organs also revealed that the production of aflatoxins was successfully inhibited by AgNPs. It was concluded that the harmful effects of aflatoxins produced by A. ochraceus can be successfully neutralized by using J. regia-mediated AgNPs.

MnO2 Doped with Ag Nanoparticles and Their Applications in Antimicrobial and Photocatalytic Reactions

A wide range of nanoparticles have been produced for photocatalysis applications. Nonetheless, degrading organic dyes requires nanoparticles that are efficient and excellent. As a photocatalyst, pure manganese oxide (MnO2) was prepared via a sol–gel method using silver (Ag) nanoparticles of transition metal oxide. In addition to X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX), the crystal structure and elemental composition were analysed. According to XRD data, the transition metal of MnO2 oxide is highly pure and has a small crystallite size. The presence of functional groups was confirmed and clarified using Fourier-transform infrared spectra (FTIR). By irradiating the transition pure and doped MnO2 photocatalysts with visible light, the UV-vis, μ-Raman, and surface areas were determined. As a result, of using the photocatalysts with aqueous methylene blue (MB) solutions under visible light irradiation, the MnO2 doped with Ag nanoparticles demonstrated high degradation efficiencies and were utilised to establish heterogeneous photocatalysis dominance. In this paper, we demonstrate that the photocatalytic efficiency of transition metal oxides is exclusively determined by the particle size and surface area of nano-sized materials. Due to their high surface charge ratio and different surface orientations, have the highest photocatalytic efficiency. Generally, MnO2 doped with Ag nanoparticles is resistant to bacteria of both Gram-positive and Gram-negative types (B. sublittus and Escherichia coli). There is still a need for more research to be performed on reducing the toxicity of metal and metal oxide nanoparticles so that they can be used as an effective alternative to antibiotics and disinfectants, particularly for biomedical applications.

Evaluation of Antibacterial and Anticancer Characteristics of Silver Nanoparticles Synthesized from Plant Extracts of Wrightia tinctoria and Acacia chundra

The study showed the ability to synthesize environmentally friendly silver nanoparticles (AgNPs) using extracts from Wrightia tinctoria seeds and Acacia chundra stems. Surface plasmon resonance peaks in the UV-Vis absorption spectra of both plant extracts verified AgNP synthesis. The structural and morphological properties of the AgNPs were investigated using analytical techniques such as XRD, FTIR, TEM, and EDAX. The AgNPs have an FCC crystalline structure, according to XRD study, and their sizes range from 20 to 40 nm, according to TEM images. Based on the results, these plant extracts have been identified as suitable bioresources for AgNP production. The study also showed that both AgNPs had significant levels of antibacterial activity when tested on four different microbial strains using the agar-well diffusion method. The bacteria tested included two Gram-positive strains (Staphylococcus aureus and Micrococcus luteus) and two Gram-negative strains (Proteus vulgaris and Escherichia coli). Furthermore, the AgNPs were found to have a significant anticancer effect on MCF-7 cell lines, suggesting that they may be useful in therapeutic applications. Overall, this research highlights the potential of the plant extracts considered as a source for synthesizing eco-friendly AgNPs with potential applications in medicine and other fields.

Green synthesis of metal-based nanoparticles for sustainable agriculture

The large-scale use of conventional pesticides and fertilizers has put tremendous pressure on agriculture and the environment. In recent years, nanoparticles (NPs) have become the focus of many fields due to their cost-effectiveness, environmental friendliness and high performance, especially in sustainable agriculture. Traditional NPs manufacturing methods are energy-intensive and harmful to environment. In contrast, synthesizing metal-based NPs using plants is similar to chemical synthesis, except the biological extracts replace the chemical reducing agent. This not only greatly reduces the used of traditional chemicals, but also produces NPs that are more economical, efficient, less toxic, and less polluting. Therefore, green synthesized metal nanoparticles (GS-MNPs) are widely used in agriculture to improve yields and quality. This review provides a comprehensive and detailed discussion of GS-MNPs for agriculture, highlights the importance of green synthesis, compares the performance of conventional NPs with GS-MNPs, and highlights the advantages of GS-MNPs in agriculture. The wide applications of these GS-MNPs in agriculture, including plant growth promotion, plant disease control, and heavy metal stress mitigation under various exposure pathways, are summarized. Finally, the shortcomings and prospects of GS-MNPs in agricultural applications are highlighted to provide guidance to nanotechnology for sustainable agriculture.

Enhancement of antibacterial activity through phyto-fabrication of silver nanoparticles with Ficus thonningii aqueous extracts

The World Health Organisation reports higher levels of bacterial resistance to cephalosporins and carbapenems of above 54%. The sufficient redox capabilities of Ficus thonningii phytochemicals for Ag⁺ reduction to Ag⁰ and ultimately aggregation to nucleation are exploited for the first time in attempting to enhance the antibacterial activity. Solution colour change to brown due to surface plasmon resonance phenomenon confirmed nanoparticle fabrication with a UV/Vis absorption peak at 426 nm. Fourier Transform Infrared spectra revealed functional groups (C=C at 1620–1680 cm⁻¹; C=H at 1400–1600 cm⁻¹ aromatics) for encapsulation, stabilisation, and reduction of the silver ion. The Dynamic Light Scattering technique verified F. thonningii encapsulated silver nanoparticles particle size of 57.84 nm with a negative zeta potential (−19.8 mV) as proof of stability. The surface, shape and topographical features were shown by Scanning Electron Microscopy as spherical orientations. An enhanced antimicrobial efficacy was displayed by the nanoparticles (inhibition zones of 26.1, 24.1 and 15.2 mm from 11.5, 10.6 and 6.5 mm) for Staphylococcus aureus, Streptococcus pyrogenes and Escherichia coli, respectively, compared to Flucloxacillin standard that was in the ranges of 21.5, 23.5 and 25.7 mm. The enhanced potency provides a basis for diversified approaches of generating novel drugs for treating bacterial infections.

Green Metallic Nanoparticles: Biosynthesis to Applications

Current advancements in nanotechnology and nanoscience have resulted in new nanomaterials, which may pose health and environmental risks. Furthermore, several researchers are working to optimize ecologically friendly procedures for creating metal and metal oxide nanoparticles. The primary goal is to decrease the adverse effects of synthetic processes, their accompanying chemicals, and the resulting complexes. Utilizing various biomaterials for nanoparticle preparation is a beneficial approach in green nanotechnology. Furthermore, using the biological qualities of nature through a variety of activities is an excellent way to achieve this goal. Algae, plants, bacteria, and fungus have been employed to make energy-efficient, low-cost, and nontoxic metallic nanoparticles in the last few decades. Despite the environmental advantages of using green chemistry-based biological synthesis over traditional methods as discussed in this article, there are some unresolved issues such as particle size and shape consistency, reproducibility of the synthesis process, and understanding of the mechanisms involved in producing metallic nanoparticles via biological entities. Consequently, there is a need for further research to analyze and comprehend the real biological synthesis-dependent processes. This is currently an untapped hot research topic that required more investment to properly leverage the green manufacturing of metallic nanoparticles through living entities. The review covers such green methods of synthesizing nanoparticles and their utilization in the scientific world.

Green Synthesis of Superparamagnetic Iron Oxide Nanoparticles with Eucalyptus globulus Extract and Their Application in the Removal of Heavy Metals from Agricultural Soil

The green synthesis of metal oxide nanoparticles is presented as an excellent sustainable alternative for achieving nanostructures, with potential applications. This research provides important information regarding the influence of the type of solvent used in extracting organic reducing agents from E. globulus on the FeO NPs green synthesis protocol. A broad approach to characterization is presented, where UV-vis spectrophotometry suggests the presence of this type of nanoparticulate material. Likewise, the reduction mechanism was evaluated by FT-IR and the magnetic properties were evaluated by PPSM. In addition, characterizations were linked via elemental analysis (EDX), crystallographic characterization (XRD), electron microscopy (SEM/STEM), and Z potential to evaluate colloidal stability. The results show the influence of the type of solvent used for the extraction of organic reducing agents from E. globulus, and the effect on the synthesis of FeO NPs. In addition, the nanostructure material obtained showed excellent efficiency in the remediation of agricultural soil, eliminating metals such as Cr-VI, Cd, and, to a lesser extent, Pb.

Multifarious global flora fabricated phytosynthesis of silver nanoparticles: a green nanoweapon for antiviral approach including SARS-CoV-2

The progressive research into the nanoscale level upgrades the higher end modernized evolution with every field of science, engineering, and technology. Silver nanoparticles and their broader range of application from nanoelectronics to nano-drug delivery systems drive the futuristic direction of nanoengineering and technology in contemporary days. In this review, the green synthesis of silver nanoparticles is the cornerstone of interest over physical and chemical methods owing to its remarkable biocompatibility and idiosyncratic property engineering. The abundant primary and secondary plant metabolites collectively as multifarious phytochemicals which are more peculiar in the composition from root hair to aerial apex through various interspecies and intraspecies, capable of reduction, and capping with the synthesis of silver nanoparticles. Furthermore, the process by which intracellular, extracellular biological macromolecules of the microbiota reduce with the synthesis of silver nanoparticles from the precursor molecule is also discussed. Viruses are one of the predominant infectious agents that gets faster resistance to the antiviral therapies of traditional generations of medicine. We discuss the various stages of virus targeting of cells and viral target through drugs. Antiviral potential of silver nanoparticles against different classes and families of the past and their considerable candidate for up-to-the-minute need of complete addressing of the fulminant and opportunistic global pandemic of this millennium SARS-CoV2, illustrated through recent silver-based formulations under development and approval for countering the pandemic situation.

Graphical abstract

Preparation of Tris-Tetrazole-Based Metallogels and Stabilization of Silver Nanoparticles: Studies on Reduction Catalysis and Self-Healing Property

An ionic multifunctional gelator molecule triethylammonium 5-(3,5-bis((1H-tetrazol-5-yl)carbamoyl)benzamido)tetrazol-1-ide G7 is synthesized and characterized by spectroscopic tools and mass spectrometry. G7 tends to form a stable organogel in a mixture of N,N-dimethylformamide/dimethylsulfoxide (DMF/DMSO) and water. Introduction of different metal perchlorate salts in a DMSO solution of G7 furnished a series of metallogels M¹G7, M²G7, M³G7, M⁴G7, M⁵G7, M⁶G7, and M⁷G7 [M¹ = Fe(III), M² = Co(II), M³ = Cu(II), M⁴ = Zn(II), M⁵ = Ag(I), M⁶ = Ni, and M⁷ = Fe(II)]. Among them, M¹G7, M³G7, M⁴G7, M⁶G7, and M⁷G7 help individually in the synthesis and stabilization of bimetallic nanocomposites containing silver nanoparticles (AgNPs). Iron(III)-containing nanocomposites M¹G7AgNPs have been utilized in the form of catalysts in the reduction reaction of nitroaromatic compounds to corresponding amines with a quantitative yield. The organogel G7 has also shown the abilities to absorb different metal ions from aqueous solutions and allow selective transition of M¹G7 from the gel state to the crystalline state. Fe(III) formed dual metallogels with Zn(II), which can be used for further applications. Furthermore, the nanocomposite M¹G7AgNP powder, in the presence of the organogel G7, gets converted into a nanostructured metallogel, which shows exclusive self-healing properties. This is the first example where a nanocomposite powder contains the dual-metal system (Fe(III) and Ag(0)) and shows a reduction catalytic property, and its nanostructured dual-metallogel form manifests the self-healing property in a fabricated metallogel.

Recent advances in anticancer and antimicrobial activity of silver nanoparticles synthesized using phytochemicals and organic polymers

Development of eco-friendly synthetic methods has resulted in the production of biocompatible Ag NPs for applications in medical sector. To overcome the prevailing antibiotic resistance in bacteria, Ag NPs are being extensively researched over the past few years due to their broad spectrum and robust antimicrobial properties. Silver nanoparticles are also being studied widely in advanced anticancer therapy as an alternative anticancer agent to combat cancer in an effective manner. Keeping this backdrop in consideration, this review aims to provide an extensive coverage of the recent progresses in the green synthesis of Ag NPs specifically using plant derived reducing agents such phytochemicals and numerous other biopolymers. Current development in antimicrobial activity of Ag NPs against various pathogens has been deliberated at length. Recent advances in potent anticancer activity of the biogenic Ag NPs against various cancerous cell lines has also been discussed in detail. Mechanistic details of the synthesis of Ag NPs, their anticancer and antimicrobial action has also been highlighted.

Phyto-fabrication, purification, characterisation, optimisation, and biological competence of nano-silver

Published studies indicate that virtually any kind of botanical material can be exploited to make biocompatible, safe, and cost-effective silver nanoparticles. This hypothesis is supported by the fact that plants possess active bio-ingredients that function as powerful reducing and coating agents for Ag+. In this respect, a phytomediation method provides favourable monodisperse, crystalline, and spherical particles that can be easily purified by ultra-centrifugation. However, the characteristics of the particles depend on the reaction conditions. Optimal reaction conditions observed in different experiments were 70-95 °C and pH 5.5-8.0. Green silver nanoparticles (AgNPs) have remarkable physical, chemical, optical, and biological properties. Research findings revealed the versatility of silver particles, ranging from exploitation in topical antimicrobial ointments to in vivo prosthetic/organ implants. Advances in research on biogenic silver nanoparticles have led to the development of sophisticated optical and electronic materials with improved efficiency in a compact configuration. So far, eco-toxicity of these nanoparticles is a big challenge, and no reliable method to improve the toxicity has been reported. Therefore, there is a need for reliable models to evaluate the effect of these nanoparticles on living organisms.

Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed.

Phytofabrication of Silver Nanoparticles Using Three Flower Extracts and Their Antibacterial Activities Against Pathogen Ralstonia solanacearum Strain YY06 of Bacterial Wilt

Bacterial wilt caused by the phytopathogen Ralstonia solanacearum (R. solanacearum) is a devastating plant disease worldwide. The use of bactericides and antibiotics for controlling bacterial wilt has shown low efficiency and posed environmental risks. This study was to phytofabricate silver nanoparticles (AgNPs) mediated by canna lily flower (Canna indica L.), Cosmos flower (Cosmos bipinnata Cav.), and Lantana flower (Lantana camara L.). The biosynthesized AgNPs were confirmed and characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), and scanning electron microscopy (SEM). UV-visible spectra showed absorption peak bands at 448, 440, and 428 nm of AgNPs synthesized by C. indica L., C. bipinnata Cav., and L. camara L. flowers, respectively. FTIR spectra confirmed that biofunctional groups of flower extract were involved in the synthesis of AgNPs as capping and stabilizing agents. The spherical AgNPs synthesized by C. indica L., C. bipinnata Cav., and L. camara L. flowers had average diameters of 43.1, 36.1, and 24.5 nm, respectively. The AgNPs (10.0 μg/ml) synthesized by L. camara L. flower had a maximum suppression zone of 18 mm against R. solanacearum strain YY06 compared with AgNPs synthesized by C. indica L. and C. bipinnata Cav. flowers. Bacterial growth, biofilm formation, swimming motility, efflux of nucleic acid, cell death, cell membrane damage, and reactive oxygen species (ROS) generation of R. solanacearum were also negatively affected by AgNPs with high concentration and small size. In summary, the biosynthesized AgNPs can be used as an efficient and environmentally friendly antibacterial agent to reasonably inhibit R. solanacearum.

Flower shaped ZnO—NPs; phytofabrication, photocatalytic, fluorescence quenching, and photoluminescence activities

Phytofabrication of Zinc Oxide nanoparticles (ZnO–NPs) through Nephelium lappaceum L. and Garcinia mangostana L. plants’ wastes were achieved as an environmentally friendly method of synthesizing nanoparticles. Biogenic ZnO–NPs were characterized by Ultra Violet Visible (UV–vis) spectrophotometry, Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Energy Dispersive Energy (EDX ), and Fourier Transform Infrared spectroscopy (FTIR). UV- Visible absorption of ZnO–NPs indicated a characteristic absorption band at 362–368 nm region. The synthesized nanoparticles were flower in shape, as shown by the SEM images, and they were further elucidated by the TEM images. ZnO-NP synthesized via Rambutan Peel Extract (RPE), Rambutan Seed Extract (RSE), Mangosteen Peel Extract (MPE) and Mangosteen Seed Extract (MSE) showed the average particle size of 29 nm–184 nm, 86 nm–260 nm, 92 nm–247 nm, and 233 nm–334 nm respectively. FTIR spectra demonstrated peaks at 3269–3500 cm−1, 2308–2361 cm−1, 2103–2110 cm−1 and 1630–1640 cm−1, 586–632 cm−1 for the plant extracts, whereas an additional peak appeared within the range of 458–499 cm−1 in ZnO–NPs spectra. The photocatalytic activity of the synthesized ZnO–NPs was measured by the degradation of Methylene Blue under sunlight. The highest degradation of Methylene Blue dye was detected in ZnO—NPs synthesized using the seed extract of Nephelium lappaceum L., where a Half-life of 78 min and 97% degradation efficiency at 150 min time frame was observed. The ZnO–NPs were identified to possess fluorescence quenching ability of Rhodamine B. The highest quenching ability was recorded in ZnO–NPs synthesized via Garcinia mangostana L. seed. The Photoluminescence study showed that the intensity of spectral lines of biogenic ZnO–NPs were higher compared with the chemically synthesized ZnO–NPs.

Evaluation of the antimicrobial activity of silver nanoparticles obtained by microwave-assisted green synthesis using Handroanthus impetiginosus (Mart. ex DC.) Mattos underbark extract

We describe here a green method for the preparation of silver nanoparticles (AgNPs), by a microwave-assisted synthesis route using Handroanthus impetiginosus underbark extract, with antibacterial activity. After optimizing the synthesis parameters with a Box-Benhken designed experiment, samples were characterized by powder XRD, TEM, UV-Vis spectroscopy, FTIR and zetametry. Using the overall optimized conditions of synthesis - time of reaction 15 min at 200 °C and plant extract/AgNO3 volume ratio equal to 10% - highly crystalline ∼13.4 nm-sized spherical AgNPs in a well-dispersed colloidal state were obtained. It was also proved that the plant extract compounds act as reductant and capping agents during synthesis to functionalize AgNPs, resulting in a negatively charged surface with high values of zeta potential in a wide range of pH, from acidic to alkaline media. Biological activity tests against Staphylococcus aureus and Escherichia coli and cell viability experiments showed that synthesized AgNPs were not toxic to HaCaT mammalian cells and presented a high efficiency against Gram-positive bacteria (S. aureus). This was associated with the synergistic combination of AgNP silver cores with the capping layer containing natural compounds with antimicrobial properties and considered an alternative to the AgNPs commonly obtained from conventional routes that present antibacterial effectiveness preferentially against Gram-negative strains.

Silver nanoparticles and silver salt (AgNO3) elicits morphogenic and biochemical variations in callus cultures of sugarcane

The research work was arranged to check the role of AgNPs and silver ions on callus cells of sugarcane (Saccharum spp. cv CP-77,400). AgNPs were synthesized chemically and characterized by UV-Vis spectra, XRD and SEM. AgNPs and silver ions were applied in various concentrations (0, 20, 40, 60 ppm) to sugarcane calli and the induced stress was characterized by studying various morphological and biochemical parameters. AgNPs and silver ions treatments produced high levels of malondialdehyde, proline, proteins, TP and TF contents. Similarly, CAT, SOD and POX activity was also significant in both treatments. The lower concentration of AgNPs and silver ions (20 ppm) provided maximum intracellular GSH level. This work mainly showed effects of AgNPs and silver ions on sugarcane calli in terms of morphological aberrations and cell membrane damage due to severe oxidative stress and production of enhanced levels of enzymatic and non-enzymatic antioxidants as self-defence to tolerate oxidative stress by scavenging reactive oxygen species. These preliminary findings will provide the way to study ecotoxicity mechanism of the metal ions and NPs in medicine industry and in vitro toxicity research. Furthermore, silver ions alone and their chemically synthesised AgNPs can be used for various biomedical applications in future.

Antimicrobial potentials of medicinal plant's extract and their derived silver nanoparticles: A focus on honey bee pathogen

Infectious (or Communicable) diseases are not only the past but also the present problem in developing as well as developed countries. It is caused by various pathogenic microbes like fungi, bacteria, parasites and virus etc. The medicinal plants and nano-silver have been used against the pathogenic microbes. Herbal medicines are generally used for healthcare because they have low price and wealthy source of antimicrobial properties. Like medicinal plants, silver nanoparticles also have emergent applications in biomedical fields due to their immanent therapeutic performance. Here, we also explore the various plant parts such as bark, stem, leaf, fruit and seed against Gram negative and Gram-positive bacteria, using different solvents for extraction i.e. methanol, ethyl acetate, chloroform, acetone, n. hexane, butanol, petroleum ether and benzene. Since ancient to date most of the countries have been used herbal medicines, but in Asia, some medicinal plants are commonly used in rural and backward areas as a treatment for infectious diseases. In this review, we provide simple information about medicinal plants and Silver nanoparticles with their potentialities such as antiviral, bactericidal and fungicidal. Additionally, the present review to highlights the versatile applications of medicinal plants against honey bee pathogen such as fungi (Ascosphaera apis), mites (Varroa spp. and Tropilaelaps sp.), bacteria (Melissococcus plutonius Paenibacillus larvae), and microsporidia (Nosema apis and Nosema ceranae). In conclusion, promising nonchemical (plant extracts) are innocuous to adult bees. So, we strongly believed that this effort was made to evaluate the status of medicinal plants researches globally.

Green nanotechnology: a review on green synthesis of silver nanoparticles - an ecofriendly approach

Background: Nanotechnology explores a variety of promising approaches in the area of material sciences on a molecular level, and silver nanoparticles (AgNPs) are of leading interest in the present scenario. This review is a comprehensive contribution in the field of green synthesis, characterization, and biological activities of AgNPs using different biological sources. Methods: Biosynthesis of AgNPs can be accomplished by physical, chemical, and green synthesis; however, synthesis via biological precursors has shown remarkable outcomes. In available reported data, these entities are used as reducing agents where the synthesized NPs are characterized by ultraviolet-visible and Fourier-transform infrared spectra and X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Results: Modulation of metals to a nanoscale drastically changes their chemical, physical, and optical properties, and is exploited further via antibacterial, antifungal, anticancer, antioxidant, and cardioprotective activities. Results showed excellent growth inhibition of the microorganism. Conclusion: Novel outcomes of green synthesis in the field of nanotechnology are appreciable where the synthesis and design of NPs have proven potential outcomes in diverse fields. The study of green synthesis can be extended to conduct the in silco and in vitro research to confirm these findings.

Application of the combinatorial approaches of medicinal and aromatic plants with nanotechnology and its impacts on healthcare

BACKGROUND

Medicinal and aromatic plants are natural raw materials. Since ancient times these herbal materials are being commonly used as herbal drugs, food products, and cosmetics. The phytomolecules isolated from the medicinal and aromatic plants (MAPs) are in high demand specifically in drug industries. However, these phytomolecules have certain limitations of low absorption, high toxicity, and other side effects, bioavailability and efficacy. These limitations may be overcome by using nanotechnological tools. The plant extract or essential oil of MAPs are also useful in the synthesis of nanoparticles. In future this combinatorial application of MAPs and nanotechnology would be advantageous in the healthcare area.

METHODS

Literature search was performed using databases like Pubmed, Scopus and Google Scholar with the keywords "nanoparticles," "phytomolecules," "medicinal and aromatic plants" and "green synthesis of nanoparticles" in the text.

RESULT

Phytomolecules of medicinal and aromatic plants like curcumin, camptothecin, thymol, and eugenol have certain limitations of bioavailability, efficacy, and solubility. It limits its biological activity and therefore application in the biomedical area. The increment in the biological activity and sustained delivery was observed after the encapsulation of these potent phytomolecules encapsulated in the nanocarriers. Besides, MAPs and/or their molecules/oils mediate the synthesis of metal nanocarriers with less toxicity.

CONCLUSION

This review highlights the impact of the combination of the MAPs with the nanotechnology along with the challenges. It would be an effective technique for the efficient delivery of different phytomolecules and also in the synthesis of novel nano-materials, which escalates the opportunity of exploration of potential molecules of MAPs. Graphical abstract Graphical representation of the combinatorial approach of MAPs and nanotechnology.

Green synthesis and evaluation of silver nanoparticles for antimicrobial and biochemical profiling in Kinnow (Citrus reticulata L.) to enhance fruit quality and productivity under biotic stress

Green synthesis of silver nanoparticles (AgNPs) by utilising plant extract is an emerging class of nanotechnology. It revolutionizes all the field of biological sciences by synthesizing chemical free AgNPs. In the present study, AgNPs were synthesised by utilising Moringa oleifera leaves as the main reducing and stabilising agent and characterised through UV-visible spectroscopy, zeta analyser, X-ray diffraction spectroscopy (XRD), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). The different concentrations of biosynthesised AgNPs (10, 20, 30, and 40 ppm) were exogenously applied on the already infected plants (canker) of Citrus reticulata at different day intervals. The AgNPs at a concentration of 30 ppm was found to be most suitable concentration for creating the resistance against canker disease in Citrus reticulata. The enzymatic activities were also explored and it was found that 30 ppm concentration of biosynthesised AgNPs significantly reduced the biotic stress. Fruit quality and productivity parameters were also assessed and it was found that fruit quality and productivity were significant in response to 30 ppm concentration of biosynthesised AgNPs. The present work highlights the potent role of biosynthesised AgNPs, which can be used as biological control of citrus diseases and ultimately improving the quality and productivity of Citrus.

Effect of green synthesised silver nanoparticles on morphogenic and biochemical variations in callus cultures of kinnow mandarin (Citrus reticulata L.)

Citrus reticulata is economically important tree fruit crop in Pakistan, fortified with various nutrients and minerals including Vitamin C and secondary metabolites. Nanotechnology is a twenty‐first century science and deals with production of minute particles termed as nanoparticles. In present study, silver nanoparticles (AgNPs) were synthesised through green method by utilising leaves of Olea europea as main reducing and capping agent. The synthesised AgNPs were characterised through UV visible spectroscopy, SEM, and energy dispersive X‐ray. Furthermore, different concentrations of AgNPs (10, 20, 30 ppm) in combination with Thidiazuron (0.5, 1.0 mg/l) were added onto MS medium to study development and secondary metabolites production in callus culture of C. reticulata . Callus induction percentage (96%) was more in 20 ppm AgNPs and 1 mg/l TDZ concentration. Moreover, high total phenolic, flavonoid contents, and antioxidant activity was observed in 20 ppm AgNPs combined with 0.5 and 1 mg/l TDZ. Enzymatic components (SOD, POD and CAT) were increased in MS medium augmented with 30 ppm AgNPs and TDZ. The total protein content (TPC) was significant in callus cultures treated with TDZ only. This study provides the first evidence of green synthesised AgNPs on callus culture developments and further quantification of biochemical profiling in C. reticula.

Assessment of AgNPs exposure on physiological and biochemical changes and antioxidative defence system in wheat (Triticum aestivum L) under heat stress

The present study was designed to check the role of silver nanoparticles (AgNPs) on physiological, biochemical parameters and antioxidants of wheat (Triticum aestivum L.) under heat stress. Plant extract of Moringa oleifera was used for AgNPs synthesis followed by characterization through UV-Vis spectroscopy, SEM, XRD and Zeta analyser. Heat stress was applied in range of 35-40°C for 3 hrs/ day for 3 days to wheat plants at trifoliate stage. Heat stress decreased the RWC (13.2%), MSI (16.3%), chl a (5.2%), chl b (4.1%) and TCCs (9.9%). Wheat plants treated with AgNPs showed significant increase in RWC (12.2%), MSI (26.5%), chl a (10%), chl b (16.4%), TCCs (19%), TPC (2.4%), TFC (2.5%), TASC (2.5%), SOD (1.3%), POX (1.5%), CAT (1.8%), APX (1.2%) and GPX (1.4%), under heat stress. Lower concentration of AgNPs (50 mg/l) decreased the sugar (5.8%) and proline contents (4%), while increase was observed in higher AgNPs concentrations. Overall, AgNPs treatment enhanced thermo-tolerance in wheat plants, but the mechanism of AgNPs action needs further investigation at genome and proteome level in wheat plants under heat stress.

Biological synthesis of metallic nanoparticles (MNPs) by plants and microbes: their cellular uptake, biocompatibility, and biomedical applications

Metallic nanoparticles (MNPs) with their diverse physical and chemical properties have been applied in various biomedical domains. The increasing demand for MNPs has attracted researchers to develop straightforward, inexpensive, simple, and eco-friendly processes for the enhanced production of MNPs. To discover new biomedical applications first requires knowledge of the interactions of MNPs with target cells. This review focuses on plant and microbial synthesis of biological MNPs, their cellular uptake, biocompatibility, any biological consequences such as cytotoxicity, and biomedical applications. We highlighted the involvement of biomolecules in capping and stabilization of MNPs and the effect of physicochemical parameters particularly the pH on the synthesis of MNPs. Recently achieved milestones to understand the role of synthetic biology (SynBiol) in the synthesis of tailored MNPs are also discussed.

Biological studies of synthesized silver nanoparticles using Prosopis farcta

The evaluation of cytotoxic and apoptotic activities of silver nanoparticles (Ag-NPs) synthesized by aqueous extract of Prosopis farcta was investigated against lung (A549) and colon (HT-29) cell lines. The cytotoxic activity of nanoparticles was performed using MTT assay, while their apoptotic activity was tested using TUNEL method. The obtained results of MTT showed that the cell viability of A549 was dependent on the nanoparticles concentration and incubation time. Therefore, although the cytotoxic effect increased as the Ag-NPs concentration and incubation time heightened, yet the viability of HT-29 cells seems to be dependent only on the incubation time. The apoptotic results of the nanoparticles showed more than 50% of apoptosis on A549 and HT-29 cell lines, which in this case, HT-29 demonstrated 100% apoptosis at concentrations of more than 400 µg/ml. It seems that Ag-NPs synthesized using P. farcta extract can serve as anti-cancer agent in the treatment many cancers through creating or discovering new drug forms.

Seed germination and biochemical profile of Citrus reticulata (Kinnow) exposed to green synthesised silver nanoparticles

The biosynthesis of silver nanoparticles (AgNPs) is substantial for its applications in different fields. The Moringa oleifera leaves were used as reducing and stabilising agent for the biosynthesis of AgNPs. The synthesised AgNPs were characterised through UV-visible spectroscopy, zeta analyser, scanning electron microscopy (SEM) and energy dispersive Xray (EDX). In this study, effects of the synthesised AgNPs were also evaluated on nucellus tissues germination frequency and biochemical parameters of plant tissues. Nucellus tissues of Citrus reticulata were inoculated on MS medium supplemented with 10, 20, 30 and 40 µg/ml suspension of the synthesised AgNPs. Green synthesised AgNPs enhanced the in vitro germination because of low toxicity and nonfriendly issues. Significant results were obtained for germination parameters i.e. root and shoot length and seedling vigour index in response to 30 µg/ml suspension of green synthesised AgNPs. The 30 µ/ml suspension of AgNPs also enhanced antioxidant activity (41%) and SOD activity (0.36 nM/min/mg FW) while total phenolic content (4.7 µg/mg FW) and total flavonoid content (1.1 µg/mg FW) was significantly high when MS medium was fortified with 40 µg/ml suspension of the synthesised AgNPs. The content of total protein was significant (558 µg/BSA Eq/mg FW) in control plantlets as compared to the other treatments.