Hypericum perforatum L.-Mediated Green Synthesis of Silver Nanoparticles Exhibiting Antioxidant and Anticancer Activities

Designing iron oxide & silver nanocomposites with phyto- and fungo chemicals for biomedicine: lessons learned

Multifunctional nanoparticles for biomedical applications are widely researched and constantly developed because they provide wider possibilities for therapy and diagnostics. This work aims to summarise our findings towards the design of multifunctional complex iron oxide and silver nanoparticles (NPs) produced from the plants Zingiber officinale and Hypericum perforatum and mushrooms Amanita muscaria and Sparassis crispa. It was revealed that the antimicrobial and anticancer properties of the NPs were a consequence of the combination of silver and phyto- and fungo-chemicals originating from natural species. Moreover, the photoactive properties of the complex iron oxide and silver nanoparticles promoted photodynamic therapy (λexc = 405 nm) that significantly improved the antibacterial (E. coli, S. aureus, B. pumilus, P. fluorescence) and anticancer (HeLa, U2OS cells) effects. Notably, the gel formulations of the NPs based on hyaluronic and alginic acids had advantages over the aqueous dispersions of the NPs. For instance, being embedded into a hyaluronic acid gel, the NPs were more effective against cancer cells due to the improved uptake of hyaluronic acid by cancer cells. Another advantage of gel formulations of the NPs was connected with their microstructural properties; the nanocomposite gel adjusted its microstructure to the substrate topology, mimicking the substrate scale and pattern. Thus, complex ultrasmall iron oxide and silver nanoparticle NPs synthesized with natural extracts and their gel formulations may find diverse applications in the biomedical field, particularly for local cancer treatment and as post-operative bone or tissue scaffold after cancer or chronic osteomyelitis surgery.

Phycogenic nanoparticles efficiently catalyse pesticide degradation through a novel metabolic pathway utilizing solar light

Cypermethrin (Cy) is a widely used insecticide, leading to significant environmental contamination in homes and agricultural areas. Effective methods to minimize or eliminate insecticidal residues are essential. Seaweeds, traditionally used in agriculture as soil conditioners, offer a promising solution for remediating pesticide-contaminated soils through biogenic nanoparticle synthesis. In this study, we synthesized biogenic silver nanoparticles (UL-AgNPs) from the green seaweed Ulva lactuca Lin (Ulvaceae) to degrade Cypermethrin. The UL-AgNPs were characterized using UV-Visible spectroscopy, Scanning Electron Microscopy equipped with Energy dispersive X-ray spectroscopy, Fourier Transform Infra-red spectroscopy, X-ray diffraction, Dynamic light scattering and zeta potential analysis, confirming their presence, size (81.29 nm), structure and stability. Response surface methodology (RSM) was used to assess the catalytic concentration of photocatalyst for degradation of pesticide including variables, Cy concentration and destined exposure time duration. The degradation efficiency of UL-AgNPs was evaluated, with the highest degradation (91.2%) achieved at pH 7 after 12 h using 16.6 mg L-1 of UL-AgNPs, following pseudo-first order kinetics with a rate of 2.7 h-1. GC-MS and UV-Visible spectroscopy revealed a novel degradation pathway, where Cypermethrin was broken down into compounds like Tetradecane, Dodecane, and Tetracosanoic acid through ester cleavage and benzene ring breakdown. The study also demonstrated the reusability of UL-AgNPs for four cycles, highlighting their potential for sustainable environmental management by reducing the long-term hazards of Cypermethrin.

A study on the effect of Hypericum perforatum L. extract on vanadium toxicity in Allium cepa L

The growth of industrialization growth the risk of vanadium (V) contamination. The objective of this study was to examine the impact of 200 µg L- 1 VCI3 -induced toxicity as well as the potential protective effect of 187.5 mg L- 1 and 375 mg L- 1Hypericum perforatum (H. perforatum) extracts against this toxicity on the Allium cepa (A. cepa) model organism. For this purpose, a series of investigations were conducted on the growth physiology alterations (germination percentage, root elongation, weight gain), cytogenetic alterations (mitotic index, micronucleus, chromosomal aberrations), biochemical alterations (malondialdehyde, superoxide dismutase, catalase) and defects in meristematic tissue in A. cepa. In addition, the phenolic compound content of H. perforatum extract was determined by the LC/MS-MS method. V application negatively affected all the investigated parameters and caused a serious phytotoxic and genotoxic effect as well as oxidative stress in A. cepa. Conversely, no statistical difference was observed between the parameters of the groups treated with H. perforatum extract and those of the control group. The administration of H. perforatum extract combined with V resulted in a notable enhancement in germination percentage, root elongation, weight gain, mitotic index value, chlorophyll a level and chlorophyll b level. Additionally, it led to a reduction in micronucleus and chromosomal aberrations frequencies, as well as meristematic tissue defects. Furthermore, LC/MS-MS analysis demonstrated that H. perforatum extract contains phenolic compounds, including catechin, epicatechin, quercetin, oleuropein and rutin, which confer antioxidant properties to the extract. The study provided clear evidence that H. perforatum extract attenuates the toxic effects of V in A. cepa, which can be attributed to its high content of bioactive phenols. The findings of the study indicate that H. perforatum extract may serve as a protective natural agent for daily use against heavy metal toxicity.

Synthesis of metallic nanoparticles using biometabolites: mechanisms and applications

Bio-metabolites have played a crucial role in the recent green synthesis of nanoparticles, resulting in more versatile, safer, and effective nanoparticles. Various primary and secondary metabolites, such as proteins, carbohydrates, lipids, nucleic acids, enzymes, vitamins, organic acids, alkaloids, flavonoids, and terpenes, have demonstrated strong metal reduction and stabilization properties that can be utilized to synthesize nanomaterials and influence their characters. While physical and chemical methods were previously used to synthesize these nanomaterials, their drawbacks, including high energy consumption, elevated cost, lower yield, and the use of toxic chemicals, have led to a shift towards eco-friendly, rapid, and efficient alternatives. Biomolecules act as reducing agents through deprotonation, nucleophilic reactions, transesterification reactions, ligand binding, and chelation mechanisms, which help sequester metal ions into stable metal nanoparticles (NPs). Engineered NPs have potential applications in various fields due to their optical, electronic, and magnetic properties, offering improved performance compared to bulkier counterparts. NPs can be used in medicine, food and agriculture, chemical catalysts, energy harvesting, electronics, etc. This review provides an overview of the role of primary and secondary metabolites in creating effective nanostructures and their potential applications.

Antibacterial, antioxidant, and anti-giardia properties of the essential oil, hydroalcoholic extract, and green synthesis of the silver nanoparticles of Salvia mirzayanii plant

In this study, an environmentally-friendly, simple, and low-cost approach was developed for the production of silver nanoparticles (Ag NPs) accelerated by Salvia mirzayanii plant. The identification process involved ultraviolet-visible (UV-Vis) spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The UV-Vis spectrum exhibited a peak at 450 nm which is a characteristic surface plasmon resonance of Ag NPs. The XRD and EDS analyses confirmed the crystalline nature and the presence of silver element, while the SEM analysis displayed the production of almost spherical nanoparticles. The FTIR spectrum exhibited that the Ag NPs were functionalized with biomolecules found in the extract, which are involved in the production and stabilization of the NPs. The antibacterial activity of the essential oil, the hydroalcoholic extract and Ag NPs was examined against antibiotic-resistant bacteria, Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). The anti-Giardia activity was tested on Giardia lamblia cysts at different time intervals. The results exhibited that the MIC values for essential oil, hydroalcoholic extract and Ag NPs against S. aureus were 1.65 µL/mL, 75 mg/mL, and 0.125 mg/mL respectively. The MBC was attained 6.25 µL/mL, 300 mg/mL, and 0.25 mg/mL, for essential oil, hydroalcoholic extract and Ag NPs, respectively. The MIC values for essential oil, hydroalcoholic extract and NPs against E. coli were 3.12 µL/mL, 150 mg/mL, and 0.06 mg/mL, respectively. The MBC was determined to be 50 µL/mL, 300 mg/mL, and 0.25 mg/mL for essential oil, hydroalcoholic extract and Ag NPs, respectively. In addition, the antioxidant activity was determined using the ferric reducing antioxidant power (FRAP) test. The results indicated that the essential oil of this plant exhibited the highest antibacterial and anti-giardial properties, whereas its extract demonstrated the strongest antioxidant properties.

Green Synthesis of Silver Nanoparticle Using Black Mulberry and Characterization, Phytochemical, and Bioactivity

Synthesis of silver nanoparticles (AgNPs) using plant extracts has been proposed as a more advantageous and environmentally friendly alternative compared to existing physical/chemical methods. In this study, AgNPs were synthesized from silver nitrate using black mulberry (BM) extract. The biosynthesized AgNPs were characterized through an UV-visible spectrometer, X-ray diffraction, and transmission electron microscopy. Additionally, BM-AgNPs were subjected to antioxidant, antibacterial, anti-inflammatory, and anticancer activities. AgNPs biosynthesized from BM extract were dark brown in color and showed a strong peak at 437 nm, confirming that AgNPs were successfully synthesized. The size of AgNPs was 170.17 ± 12.65 nm, the polydispersity index was 0.281 ± 0.07, and the zeta potential value was -56.6 ± 0.56 mV, indicating that the particles were stable. The higher total phenol, flavonoid, and anthocyanin content of BM-AgNPs compared to BM extract indicates that the particles contain multiple active substances due to the formation of AgNPs. The DPPH and ABTS assays showed decreased IC50 values compared to BM extract, demonstrating improved antioxidant activity. AgNPs inhibited the growth of S. aureus and E. coli at 600 μg/mL, with minimum bactericidal concentrations determined to be 1000 and 1200 μg/mL, respectively. The anti-inflammatory activity was 64.28% at a BM-AgNPs concentration of 250 μg/mL. As the concentration increased, the difference from the standard decreased, indicating the inhibitory effect of AgNPs on bovine serum albumin denaturation. The viability of MCF-7 cells treated with BM-AgNPs was found to be significantly lower than that of cells treated with BM extract. The IC50 value of BM-AgNPs was determined to be 96.9 μg/mL. This study showed that BM-AgNPs have the potential to be used in the pharmaceutical industry as antioxidant, antibacterial, anti-inflammatory, and anticancer agents.

A systematic review on green synthesis of silver nanoparticles using plants extract and their bio-medical applications

Nanoparticles have recently become considered as a crucial player in contemporary medicine, with therapeutic uses ranging from contrast agents in imaging to carriers for the transport of drugs and genes into a specific target. Nanoparticles have the ability to have more precise molecular interactions with the human body in order to target specific cells and tissues with minimal adverse effects and maximal therapeutic outcomes. With the least number of side effects and the greatest possible therapeutic benefit, nanoparticles can target particular cells and tissues through more precise molecular interactions with the human body. The majority of global public health problems are now treated with green synthesized silver nanoparticles (AgNPs), which substantially affect the fundamental structure of DNA and proteins and thus display their antimicrobial action. AgNPs can inhibit the proliferation of tumor cells and induce oxidative stress. By inhibiting vascular endothelial growth factor (HIF)-1, pro-inflammatory mediators generated by silver nanoparticles are reduced, mucin hypersecretion is lessened, and gene activity is subsequently regulated to prevent infections. The biogenic synthesis of silver nanoparticles (AgNPs) using various plants and their applications in antibacterial, antifungal, antioxidant, anticancer, anti-inflammatory, and antidiabetic activities have been extensively discussed in this article. Also, because only natural substances are utilized in the manufacturing process, the particles that are created naturally are coated, stabilized, and play a vital role in these biomedical actions. The characterization of AgNPs, possibility of preparing AgNPSs with different shapes using biological method and their impact on functions and toxicities, impact of size, shape and other properties on AgNPs functions and toxicity profiles, limitations, and future prospects of green-mediated AgNPs have also been reported in this study. The major goal of this study is to provide readers with a comprehensive, informed, and up-to-date summary of the various AgNPs production and characterization methods and their under-investigational antioxidant, antibacterial, and anticancer, antidiabetic, antifungal and anti-inflammatory properties. This review provides instructions and suggestions for additional studies based on AgNPs. This evaluation also pushes researchers to look into natural resources like plant parts in order to create useful nanobiotechnology.

Bifunctional folic acid targeted biopolymer Ag@NMOF nanocomposite [{Zn2 (1,4-bdc) 2 (DABCO)} n] as a novel theranostic agent for molecular imaging of colon cancer by SERS

Without a doubt, cancer and its negative impact on human health have created many hurdles for people across the world since conventional approaches have not offered a reliable ability in the eradication of cancer. As a result, finding novel approaches, like using bimodal nanoparticles as a potential nanocarrier in molecular imaging and cancer therapy, is remarkably required these days. In the present study, ex-situ (Ge) and in-situ (Gi) green synthesized silver (Ag) nanoparticles entrapped in metal-organic framework nanocomposites (NMOF) coated with folic acid (FA) targeted chitosan (CS) was successfully developed as a novel bifunctional nanocarrier for detection and treatment of colon cancer cells. Then nanocarriers, such as NMOF-CS-FA, Ge-Ag@NMOF-CS-FA, Gi-Ag@NMOF-CS-FA, and C-Ag@NMOF-CS-FA, were characterized via FT-IR, DLS, SERS, TEM, and SEM and results have potentially confirmed the quality and quantity of synthesized nanocomposites. The hydrodynamic diameters of NMOF-CS, Ge-Ag@NMOF-CS, Gi-Ag@NMOF-CS, and C-Ag@NMOF-CS specimens were measured at around 99.7 ± 10 nm, 110 ± 10 nm, 118 ± 10 nm, 115 ± 10 nm, respectively. Also, the PDI values less than 0.2 confirm the reliable distribution of these nanocomposites. Afterward, the cell viability assay was conducted on HCT116 and HGF cell lines for evaluating biocompatibility and targeting efficiency of nanocomposites; FA functionalized nanocomposites have intensively indicated better performance in cancer cells targeting and their inhibition, and IC50 was attained for 10 ng/mL of Ge-Ag@NMOF-CS-FA while non-targeted nanocarriers did not have toxicity more than 20 % on HCT116 colon cancer cells. Moreover, according to the results, the cell viability of HGF normal cells was at least 85 % after being exposed to different concentrations of nanocomposites for 24 h. This indicates that the synthesized nanocomposites do not have significant toxic effects on normal cells. The results indicate that this novel nanocomposite has the potential to effectively deliver drugs to cancer cells.

The Characterization and Study of Antibacterial, Free Radical Scavenging, and Anticancer Potential of Livistona chinensis-Mediated Silver Nanoparticles

In the present research, Livistona chinensis leaf extracts were utilized as reductants to bio-fabricate silver nanoparticles (LC-AgNPs) and this was followed by the evaluation of their antioxidant, antibacterial, and anticancer potential. Multiple parameters were optimized for the formation and fidelity of LC-AgNPs. The color shift of the reaction mixture from yellow to dark brown confirmed the LC-AgNPs formation. UV/VIS spectroscopy exhibited a surface plasmon resonance (SPR) band at 436 nm. The Fourier transform infrared (FTIR) spectroscopy spectrum depicted phytochemicals in the plant extract acting as bio-reducers for LC-AgNPs synthesis. The XRD pattern confirmed the presence of LC-AgNPs by showing peaks corresponding to 2θ angle at 8.24° (111), 38.16° (200), 44.20° (220), and 64.72° (311). Zetasizer analysis exhibited size distribution by intensity of LC-AgNPs with a mean value of 255.7 d. nm. Moreover, the zeta potential indicated that the AgNPs synthesized were stable. The irregular shape of LC-AgNPs with a mean average of 38.46 ± 0.26 nm was found by scanning electron microscopy. Furthermore, the antioxidant potential of LC-AgNPs was examined using a DPPH assay and was calculated to be higher in LC-AgNPs than in leaf extracts. The calculated IC50 values of the LC-AgNPs and plant extract are 85.01 ± 0.17 and 209.44 ± 0.24, respectively. The antibacterial activity of LC-AgNPs was investigated against Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis as well as Staphylococcus aureus, and maximum potential was observed after 24 h against P. aeruginosa. Moreover, LC-AgNPs exhibited maximum anticancer potential against TPC1 cell lines compared to the plant extract. The findings suggested that LC-AgNPs could be used as antioxidant, antibacterial, and anticancer agents for the cure of free-radical-oriented bacterial and oncogenic diseases.

Green Synthesis of Silver Nanoparticles Using Jacobaea maritima and the Evaluation of Their Antibacterial and Anticancer Activities

Much attention has been gained on green silver nanoparticles (green-AgNPs) in the medical field due to their remarkable effects against multi-drug resistant (MDR) microorganisms and targeted cancer treatment. In the current study, we demonstrated a simple and environment-friendly (i.e., green) AgNP synthesis utilizing Jacobaea maritima aqueous leaf extract. This leaf is well-known for its medicinal properties and acts as a reducing and stabilizing agent. Nanoparticle preparation with the desired size and shape was controlled by distinct parameters; for instance, temperature, extract concentration of salt, and pH. The characterization of biosynthesized AgNPs was performed by the UV-spectroscopy technique, dynamic light scattering, scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared. The successful formation of AgNPs was confirmed by a surface plasmon resonance at 422 nm using UV-visible spectroscopy and color change observation with a particle size of 37± 10 nm and a zeta potential of -10.9 ± 2.3 mV. SEM further confirmed the spherical size and shape of AgNPs with a size varying from 28 to 52 nm. Antibacterial activity of the AgNPs was confirmed against all Gram-negative and Gram-positive bacterial reference and MDR strains that were used in different inhibitory rates, and the highest effect was on the E-coli reference strain (MIC = 25 μg/mL). The anticancer study of AgNPs exhibited an IC50 of 1.37 μg/mL and 1.98 μg/mL against MCF-7 (breast cancer cells) and A549 (lung cancer cells), respectively. Therefore, this green synthesis of AgNPs could have a potential clinical application, and further in vivo study is required to assess their safety and efficacy.

Solvent based fractional biosynthesis, phytochemical analysis, and biological activity of silver nanoparticles obtained from the extract of Salvia moorcroftiana

Multi-drug resistant bacteria sometimes known as "superbugs" developed through overuse and misuse of antibiotics are determined to be sensitive to small concentrations of silver nanoparticles. Various methods and sources are under investigation for the safe and efficient synthesis of silver nanoparticles having effective antibacterial activity even at low concentrations. We used a medicinal plant named Salvia moorcroftiana to extract phytochemicals with antibacterial, antioxidant, and reducing properties. Three types of solvents; from polar to nonpolar, i.e., water, dimethyl sulfoxide (DMSO), and hexane, were used to extract the plant as a whole and as well as in fractions. The biosynthesized silver nanoparticles in all extracts (except hexane-based extract) were spherical, smaller than 20 nm, polydispersed (PDI ranging between 0.2 and 0.5), and stable with repulsive force of action (average zeta value = -18.55±1.17). The tested bacterial strains i.e., Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterococcus faecalis were found to be sensitive to even small concentrations of Ag-NPs, especially P. aeruginosa. The antibacterial effect of these Ag-NPs was associated with their ability to generate reactive oxygen species. DMSO (in fraction) could efficiently extract antibacterial phytochemicals and showed activity against MDR bacteria (inhibition zone = 11-12 mm). Thus, the antibacterial activity of fractionated DMSO extract was comparable to that of Ag-NPs because it contained phytochemicals having solid antibacterial potential. Furthermore, Ag-NPs synthesized from this extract owned superior antibacterial activity. However, whole aqueous extract-based Ag-NPs MIC was least (7-32 μg/mL) as compared to others.

Antibacterial Efficacy of Green Synthesized Silver Nanoparticles Using Salvia nubicola Extract against Ralstonia solanacearum, the Causal Agent of Vascular Wilt of Tomato

Ralstonia solanacearum is a phytopathogen causing bacterial wilt diseases of tomato and affecting its productivity, which leads to prominent economic losses annually. As an alternative to conventional pesticides, green synthesized nanoparticles are believed to possess strong antibacterial activities besides being cheap and ecofriendly. Here, we present the synthesis of silver nanoparticles (Sn-AgNPs) from medicinally important aqueous plant extracts of Salvia nubicola. Characterization of biologically synthesized nanoparticles was performed through UV-vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and thermogravimetric analysis. The antibacterial activity of the biosynthesized silver nanoparticles was tested against the phytopathogen R. solanacearum through in vitro experiments. Preliminary phytochemical analysis of the plant extracts revealed the presence of substantial amounts of flavonoids (57.08 mg GAE/g), phenolics (42.30 mg GAE/g), tannins, and terpenoids. The HPLC phenolic profile indicated the presence of 25 possible bioactive compounds. Results regarding green synthesized silver nanoparticles revealed the conformation of different functional groups through FTIR analysis, which could be responsible for the bioreduction and capping of Ag ions into silver NPs. TEM results revealed the spherical, crystalline shape of nanoparticles with the size in the range of 23-63 nm, which validates SEM results. Different concentrations of Sn-AgNPs (T1 (500 μg/mL) to T7 (78.1 μg/mL)) with a combination of plant extracts (PE-Sn-AgNPs) and plant extracts alone exhibited an efficient inhibition of R. solanacearum. These findings could be used as an effective alternative preparation against the bacterial wilt of tomato.

Recycling of silver nanoparticles from electronic waste via green synthesis and application of AgNPs-chitosan based nanocomposite on textile material

The main thrust of this project is the fabrication of silver nanoparticles (AgNPs) from electronic waste (PCB board) and applying it on 100% cotton fabric as an antimicrobial agent. The nanoparticle formation of silver was done by green synthesis way using an aqueous leaf extract of Eichhornia crassipes. Furthermore, chitosan was also applied to the fabric with silver nanoparticles by coating. FTIR and SEM tests characterized the fabricated silver nanoparticles, and antimicrobial tests were followed by the disc diffusion method. The SEM analysis showed an average particle size of 76.91 nm. The FTIR analysis showed the successful reduction of silver nanoparticles and the bonding with chitosan and cellulose. Besides, the EDX reports confirmed the existence of AgNPs by indicating a strong signal in the silver region. In addition, SEM characteristics analysis confirmed the uniform deposition of silver nanoparticles. Finally, the antimicrobial property was tested against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria. The antimicrobial result was found satisfactory in the case of green-synthesized recycled AgNPs. However, the effectiveness was not observed to be higher than green-synthesized pure AgNPs. In this study, the zone of inhibition of AgNPs was also compared to the reference antibiotics Ciprofloxacin.

Enhanced Antioxidant Activity and Reduced Cytotoxicity of Silver Nanoparticles Stabilized by Different Humic Materials

The current article describes the biological activity of new biomaterials combining the "green" properties of humic substances (HSs) and silver nanoparticles. The aim is to investigate the antioxidant activity (AOA) of HS matrices (macroligands) and AgNPs stabilized with humic macroligands (HS-AgNPs). The unique chemical feature of HSs makes them very promising ligands (matrices) for AgNP stabilization. HSs have previously been shown to exert many pharmacological effects mediated by their AOA. AgNPs stabilized with HS showed a pronounced ability to bind to reactive oxygen species (ROS) in the test with ABTS. Also, higher AOA was observed for HS-AgNPs as compared to the HS matrices. In vitro cytotoxicity studies have shown that the stabilization of AgNPs with the HS matrices reduces the cytotoxicity of AgNPs. As a result of in vitro experiments with the use of 2,7-dichlorodihydrofluorescein diacetate (DCFDA), it was found that all HS materials tested and the HS-AgNPs did not exhibit prooxidant effects. Moreover, more pronounced AOA was shown for HS-AgNP samples as compared to the original HS matrices. Two putative mechanisms of the pronounced AOA of the tested compositions are proposed: firstly, the pronounced ability of HSs to inactivate ROS and, secondly, the large surface area and surface-to-volume ratio of HS-AgNPs, which facilitate electron transfer and mitigate kinetic barriers to the reduction reaction. As a result, the antioxidant properties of the tested HS-AgNPs might be of particular interest for biomedical applications aimed at inhibiting the growth of bacteria and viruses and the healing of purulent wounds.

Mapping the Progress in Surface Plasmon Resonance Analysis of Phytogenic Silver Nanoparticles with Colorimetric Sensing Applications

Nanotechnology is gaining enormous attention as the most dynamic research area in science and technology. It involves the synthesis and applications of nanomaterials in diverse fields including medical, agriculture, textiles, food technology, cosmetics, aerospace, electronics, etc. Silver nanoparticles (AgNPs) have been extensively used in such applications due to their excellent physicochemical, antibacterial, and biological properties. The use of plant extract as a biological reactor is one of the most promising solutions for the synthesis of AgNPs because this process overcomes the drawbacks of physical and chemical methods. This review article summarizes the plant-mediated synthesis process, the probable reaction mechanism, and the colorimetric sensing applications of AgNPs. Plant-mediated synthesis parameters largely affect the surface plasmon resonance (SPR) characteristic due to the changes in the size and shape of AgNPs. These changes in the size and shape of plant-mediated AgNPs are elaborately discussed here by analyzing the surface plasmon resonance characteristics. Furthermore, this article also highlights the promising applications of plant-mediated AgNPs in sensing applications regarding the detection of mercury, hydrogen peroxide, lead, and glucose. Finally, it describes the future perspective of plant-mediated AgNPs for the development of green chemistry.

Synergistic Anticandidal Effectiveness of Greenly Synthesized Zinc Oxide Nanoparticles with Antifungal Agents against Nosocomial Candidal Pathogens

The high prevalence of fungal resistance to antifungal drugs necessitates finding new antifungal combinations to boost the antifungal bioactivity of these agents. Hence, the aim of the present investigation was to greenly synthesize zinc oxide nanoparticles (ZnO-NPs) using an aqueous leaf extract of Salvia officinalis and investigate their antifungal activity and synergistic efficiency with common antifungal agents. The biofabricated ZnO-NPs were characterized to detect their physicochemical properties. A disk diffusion assay was employed to investigate the antifungal effectiveness of the greenly synthesized ZnO-NPs and evaluate their synergistic patterns with common antifungal agents. The Candida tropicalis strain was detected to be the most susceptible strain to ZnO-NPs at both tested concentrations of 50 and 100 µg/disk, demonstrating relative suppressive zones of 19.68 ± 0.32 and 23.17 ± 0.45 mm, respectively. The minimum inhibitory concentration (MIC) of ZnO-NPs against the C. tropicalis strain was 40 µg/mL, whereas the minimum fungicidal concentration (MFC) was found to be 80 µg/mL. The highest synergistic efficiency of the biogenic ZnO-NPs with terbinafine antifungal agent was detected against the C. glabrata strain, whereas the highest synergistic efficiency was detected with fluconazole against the C. albicans strain, demonstrating relative increases in fold of inhibition area (IFA) values of 6.82 and 1.63, respectively. Moreover, potential synergistic efficiency was detected with the nystatin antifungal agent against the C. tropicalis strain with a relative IFA value of 1.06. The scanning electron microscopy (SEM) analysis affirmed the morphological deformations of candidal cells treated with the biosynthesized ZnO-NPs as the formation of abnormal infoldings of the cell wall and membranes and also the formation of pores in the cell wall and membranes, which might lead to the leakage of intracellular constituents. In conclusion, the potential synergistic efficiency of the biogenic ZnO-NPs with terbinafine, nystatin, and fluconazole against the tested candidal strains highlights the potential application of these combinations in formulating novel antifungal agents of high antimicrobial efficiency. The biogenic ZnO nanoparticles and antifungal drugs exhibit powerful synergistic efficiency, which highlights their prospective use in the formulation of efficient antimicrobial medications, including mouthwash, ointments, lotions, and creams for effective candidiasis treatment.

Biosynthesis of Silver Nanoparticles Functionalized with Histidine and Phenylalanine Amino Acids for Potential Antioxidant and Antibacterial Activities

Due to biochemically active secondary metabolites that assist in the reduction, stabilization, and capping of nanoparticles, plant-mediated nanoparticle synthesis is becoming more and more popular. This is because it allows for ecologically friendly, feasible, sustainable, and cost-effective green synthesis techniques. This study describes the biosynthesis of silver nanoparticles (AgNPs) functionalized with histidine and phenylalanine using the Lippia abyssinica (locally called koseret) plant leaf extract. The functionalization with amino acids was meant to enhance the biological activities of the AgNPs. The synthesized nanoparticles were characterized using UV-Visible absorption (UV-Vis), powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The surface plasmonic resonance (SPR) peak at about 433 nm confirmed the biosynthesis of the AgNPs. FTIR spectra also revealed that the phytochemicals in the plant extract were responsible for the capping of the biogenically synthesized AgNPs. On the other hand, the TEM micrograph revealed that the morphology of AgNP-His had diameters ranging from 5 to 14 nm. The antibacterial activities of the synthesized nanoparticles against Gram-positive and Gram-negative bacteria showed a growth inhibition of 8.67 ± 1.25 and 11.00 ± 0.82 mm against Escherichia coli and Staphylococcus aureus, respectively, at a concentration of 62.5 μg/mL AgNP-His. Moreover, the nanoparticle has an antioxidant activity potential of 63.76 ± 1.25% at 250 μg/mL. The results showed that the green-synthesized AgNPs possess promising antioxidant and antibacterial activities with the potential for biological applications.

Biosynthesis and Characterization of Silver Nanoparticles Produced by Parachlorella kessleri and Cyclotella spp., and the Evaluation of Their Antibacterial Activity

Green synthesis is one of the fastest and best ways for ecofriendly nanoparticle synthesis. This study aims to investigate the use of the green microalgae Parachlorella kesseleri and Cyclotella spp. for the biological synthesis of silver nanoparticles (AgNPs). This work focuses on optimizing various parameters necessary for the production and stability of AgNPs. The nanoparticle formation was confirmed by UV-Visible analysis, which revealed the surface plasmon resonance band at 420 nm. The characterization of the AgNPs was performed using UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The antimicrobial properties of these bioactive AgNPs were also tested, showing excellent antibacterial activity against six bacterial strains, Escherichia coli, multidrug-resistant Escherichia coli, Bacillus clausii, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi. The biosynthesis of AgNPs from living cultures of microalgae has remarkable antibacterial properties. Other studies are underway in our laboratory to clarify the mechanism of the biosynthesis of these nanoparticles, and their action on bacteria.

The anticancer effect of recombinant LukS-PV protein and silver nanoparticles loaded with this protein

LukS-PV is a component of Panton-Valentine leucocidin (PVL) and is secreted by Staphylococcus aureus. Silver nanoparticles exhibit considerable potential as anticancer agents and drug delivery systems. Drug delivery is a way to deliver medicinal combinations to achieve a beneficial therapeutic effect. In the current study, recombinant LukS-PV protein-loaded silver nanoparticles were prepared and their cytotoxicity effect was analyzed on human breast cancer cells and human normal embryonic kidneys cells by MTT assay. Apoptosis was investigated by staining with Annexin V/propidium iodide. The recombinant LukS-PV protein-loaded silver nanoparticles showed dose-dependent cytotoxicity and induced apoptosis in the MCF7 cells and had a lesser effect on HEK293 cells. After 24 h exposure to the recombinant LukS-PV protein-loaded silver nanoparticles (IC50), Annexin V-FITC/PI FCM revealed that 33.2% of MCF7 cells were apoptotic. In conclusion, recombinant LukS-PV protein-loaded silver nanoparticles probably cannot be a better alternative for the targeted healing approaches to cancer therapies. Hence, it is suggested that silver nanoparticles could be utilized as a delivery system for releasing toxins into cancer cells.

Silver Nanoparticle Synthesis by Rumex vesicarius Extract and Its Applicability against Foodborne Pathogens

The consumption of foods polluted with different foodborne pathogens such as fungus, viruses, and bacteria is considered a serious cause of foodborne disease in both humans and animals. Multidrug-resistant foodborne pathogens (MRFP) cause morbidity, death, and substantial economic loss, as well as prolonged hospitalization. This study reports on the use of aqueous Rumex leaf extract (ARLE) in the synthesis of silver nanoparticles (ARLE-AgNPs) with versatile biological activities. The synthesized ARLE-AgNPs had spherical shapes with smooth surfaces and an average hydrodynamic size of 27 nm. ARLE-AgNPs inhibited the growth of Escherichia coli ATCC25721, Pseudomonas aeruginosa ATCC27843, Streptococcus gordonii ATCC49716, Enterococcus faecalis ATCC700813, and Staphylococcus aureus ATCC4342. The ARLE-AgNPs were more active against Escherichia coli ATCC25721 than other harmful bacterial strains (26 ± 3 mm). The zone of inhibition for antibacterial activity ranged between 18 ± 3 mm and 26 ± 3 mm in diameter. The nanoparticles' MIC values varied from 5.19 µg/mL to 61 µg/mL, while their MBC values ranged from 46 µg/mL to 119 µg/mL. The nanoparticles that were created had antioxidant potential. The cytotoxic activity was tested using normal fibroblast cell lines (L-929), and the enhanced IC50 value (764.3 ± 3.9 g/mL) demonstrated good biological compatibility. These nanoparticles could be evolved into new antibacterial compounds for MRFP prevention.

The effect of different aqueous solutions ratios of Ocimum basilicum utilized in AgNPs synthesis on the inhibition of bacterial growth

This study examined the effect of varying concentrations of Ocimum basilicum aqueous extract, which was done via the green synthesis of Silver nanoparticles (AgNPs), on the identification of the most effective concentration for bacteria inhibitory activity. Different concentrations of the aqueous Ocimum basilicum extract (0.25, 0.50, 0.75 and 1.00 mM) were used as reducing and stabilizing agent to synthesize AgNPs by means of the reduction method. The crystal structure and morphology of the NPs were characterized UV-Vis spectra, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial efficacy of AgNPs was studied against E. coli ATCC 35218 using well diffusion, MIC, MBC, and time-kill curve. The dark yellow color of the Ocimum basilicum aqueous solution indicates the successful synthesis process of the AgNPs. UV-spectra of the AgNPs display a gradual increase of absorption in sequence with concentration increase of aqueous Ocimum basilicum extract solution from 0.25 to 1.00 mM. This, in turn, led to a shift in the wavelength from 488 to 497 nm, along with a change in the nanoparticle size from 52 to 8 nm. The tests also showed a high activity of the particles against bacteria (E. coli), ranging between 15.6 and 62.5 µg/ml. Based on AgNPs, it was confirmed that an aqueous Ocimum basilicum extract can be used as an effective, reducing and stabilizing agent for the synthesis of different sizes of AgNPs based on the solvent concentration. The AgNPs also proved to be effective in inhibiting and killing bacteria.

Silver Nanoparticles Synthesized from Abies alba and Pinus sylvestris Bark Extracts: Characterization, Antioxidant, Cytotoxic, and Antibacterial Effects

In recent years, phytofunctionalized AgNPs have attracted great interest due to their remarkable biological activities. In the present study, AgNPs were synthesized using Abies alba and Pinus sylvestris bark extracts. The chemical profile of these bark extracts was analyzed by LC-HRMS/MS. As a first step, the synthesis parameters (pH, AgNO₃ concentration, ratio of bark extract and AgNO₃, temperature, and reaction time) were optimized. The synthesized AgNPs were characterized by ATR-FTIR spectroscopy, DLS, SEM, EDX, and TEM. Their antioxidant, cytotoxic, and antibacterial properties were evaluated by the DPPH, ABTS, MTT, and broth microdilution assays, respectively. Abies alba and Pinus sylvestris bark extract-derived AgNPs were well-dispersed, spherical, small (average particle size of 9.92 and 24.49 nm, respectively), stable (zeta potential values of -10.9 and -10.8 mV, respectively), and cytotoxic to A-375 human malignant melanoma cells (IC₅₀ = 2.40 ± 0.21 and 6.02 ± 0.61 μg/mL, respectively). The phytosynthesized AgNPs also showed antioxidant and antibacterial effects.

Current Trends and Prospects for Application of Green Synthesized Metal Nanoparticles in Cancer and COVID-19 Therapies

Cancer and COVID-19 have been deemed as world health concerns due to the millions of lives that they have claimed over the years. Extensive efforts have been made to develop sophisticated, site-specific, and safe strategies that can effectively diagnose, prevent, manage, and treat these diseases. These strategies involve the implementation of metal nanoparticles and metal oxides such as gold, silver, iron oxide, titanium oxide, zinc oxide, and copper oxide, formulated through nanotechnology as alternative anticancer or antiviral therapeutics or drug delivery systems. This review provides a perspective on metal nanoparticles and their potential application in cancer and COVID-19 treatments. The data of published studies were critically analysed to expose the potential therapeutic relevance of green synthesized metal nanoparticles in cancer and COVID-19. Although various research reports highlight the great potential of metal and metal oxide nanoparticles as alternative nanotherapeutics, issues of nanotoxicity, complex methods of preparation, biodegradability, and clearance are lingering challenges for the successful clinical application of the NPs. Thus, future innovations include fabricating metal nanoparticles with eco-friendly materials, tailor making them with optimal therapeutics for specific disease targeting, and in vitro and in vivo evaluation of safety, therapeutic efficiency, pharmacokinetics, and biodistribution.

Ziziphus spina-christi extract-stabilized novel silver nanoparticle synthesis for combating Fusarium oxysporum-causing pepper wilt disease: in vitro and in vivo studies

The novelty of the present study is studying the ability of aqueous Ziziphus spina-christi leaves' extract (ZSCE) to produce eco-friendly and cost-effective silver nanoparticles (Ag NPs) against Fusarium wilt disease. Phytochemical screening of ZSCE by HPLC showed that they contain important antimicrobial substances such as Rutin, Naringin, Myricetin, Quercetin, Kaempferol, Hesperidin, Syringeic, Eugenol, Pyrogallol, Gallic and Ferulic. Characterization methods reveal a stable Ag NPs with a crystalline structure, spherical in shape with average particle size about 11.25 nm. ZSCE and Ag NPs showed antifungal potential against F. oxysporum at different concentrations with MIC of Ag NPs as 0.125 mM. Ag NPs treatment was the most effective, as it gave the least disease severity (20.8%) and the highest protection rate (75%). The application of ZSCE or Ag NPs showed a clear recovery, and its effectiveness was not limited for improving growth and metabolic characteristics only, but also inducing substances responsible for defense against pathogens and activating plant immunity (such as increasing phenols and strong expression of peroxidase and polyphenol oxidase as well as isozymes). Owing to beneficial properties such as antifungal activity, and the eco-friendly approach of cost and safety, they can be applied in agricultural field as novel therapeutic nutrients.

Green Synthesis of Characterized Silver Nanoparticle Using Cullen tomentosum and Assessment of Its Antibacterial Activity

Plants serve as an important source of medicine and provide suitable candidate compounds to produce eco-friendly therapeutic agents. They also represent a source of bio-reducer and stabilizer for the development of nanoparticles for downstream applications. This study focused on the green synthesis of silver nanoparticle (CTAgNP) using Cullen tomentosum (Thunb.) J.W. Grimes acetone extract and the evaluation of the antibacterial activity of the plant extract and biogenic nanoparticles against two Gram-positive bacteria strains, namely Bacillus cereus and Staphylococcus aureus. In addition, the phytochemical profile of C. tomentosum was established using liquid chromatography-mass spectrometry (LC-MS). The antibacterial effect of the extract and CTAgNP was moderate based on the minimum inhibitory concentration (MIC) values obtained. The MIC values of 2.6 mg/mL and 3.1 mg/mL were recorded for C. tomentosum extract against B. cereus and S. aureus, respectively. On the other hand, the CTAgNP had MIC values of 1.5 mg/mL and 2.6 mg/mL against B. cereus and S. aureus, respectively. The nanoparticle exhibited surface charge of -37 ± 7.67 mV and average hydro-dynamic size of 145 nm. X-ray diffraction illustrates that metallic nanoparticles were formed and had a face-centered cubic structure. Microscopic and spectroscopic techniques revealed that the CTAgNP was covered by a protective shell layer constituted of organic compounds originating from the plant extract. The acetone extract of C. tomentosum could be useful to the bio-pharma industries in the large-scale manufacture of nanoparticle-based medications to fight against microbes that constitute a threat to the survival of humanity.

Isotropic Silver Nanoparticles from Cytobacillus kochii Strain SW6 Isolated from Bay of Bengal Sea Sediment Water and Their Antimicrobial, Antioxidant, and Catalytic Potential

Green synthesis of nanoparticles provides numerous advantages over physical and chemical methods because of low toxicity, high yields, cost-effectiveness, environmentally benign, and energy efficiency. Therefore, we focused on the facile and green synthesis of isotropic silver nanoparticles using the metabolic extract of Cytobacillus kochii. During synthesis, the physicochemical parameters were optimized and validated using the response surface methodology statistical tool. The presence of potent bioactive compounds that aid in the biofabrication of nanoparticles was identified in the gas chromatography-mass spectroscopy analysis and the synthesis was confirmed by surface plasmon resonance peak at 420 nm. Characterization of nanoparticles was performed by high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and X-ray diffraction. The synthesized nanoparticles showed potent antioxidant properties and displayed an excellent catalytic reduction potential in the degradation of hazardous dyes, such as methylene blue, phenol red, and 4-nitrophenol. Furthermore, compared to the chemically synthesized silver nanoparticles and crude extract, the biogenic silver nanoparticles exhibited a broad-spectrum antimicrobial potential. Our results demonstrate that the reported silver nanoparticles with unique characteristics might be of great promise as biomedical and catalytic agents for industrial applications.

Eco-Friendly Preparation of Silver Nanoparticles and Their Antiproliferative and Apoptosis-Inducing Ability against Lung Cancer

In the present study, the anti-proliferative and apoptotic potential of Tabebuia roseo-alba in lung cancer was assessed. Silver nanoparticles (AgNPs) of T. roseo-alba were synthesized using an ethanolic extract and characterized by adopting various parameters. Herein, the eco-friendly, cost-effective, and green synthesis of AgNPs was evaluated using an ethanolic extract of T. roseo-alba. The as-synthesized AgNPs were then characterized using various characterization techniques, such as UV-visible spectroscopy (UV-vis), X-ray powder diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The AgNPs are crystalline, spherical, and highly stable AgNPs of varying sizes in the range of 5-20 nm. The anticancer activity of the ethanolic extract of T. roseo-alba and its AgNPs was determined using an MTT assay. The results indicated that, although both samples showed prominent anti-proliferative activity on lung cancer cell lines, the AgNPs of T. roseo-alba were found to be more potent than the ethanolic extract. Further, apoptosis induction ability was evaluated by FITC Annexin V and PI staining, the results of which demonstrated the efficiency of the ethanolic extract of T. roseo-alba and its AgNPs in causing oxidative stress and subsequent cellular death. This was subsequently further confirmed by measuring the mitochondrial membrane potential after staining the cells with JC1. The apoptotic mode of cell death was further confirmed by DNA fragmentation and caspase assays using Western blot analysis.

Phytosynthesis of Silver Nanoparticle (AgNPs) Using Aqueous Leaf Extract of Knoxia sumatrensis (Retz.) DC. and Their Multi-Potent Biological Activity: An Eco-Friendly Approach

Green synthesis of silver nanoparticles (AgNPs) has gained greater interest among chemists and researchers in this current scenario. The present research investigates the larvicidal and anti-proliferation activity of AgNPs derived from Knoxia sumatrensis aqueous leaf extract (K. sumatrensis-ALE) as a potential capping and reducing candidate. The synthesized AgNPs were characterized through-UV-spectra absorption peak at 425 nm. The XRD and FT-IR studied displayed the crystalline nature and presence of functional groups in prepared samples. FE-SEM showed the hexagonal shape of NPs with the size of 7.73 to 32.84 nm. The synthesized AgNPs displayed superior antioxidant and anti-proliferative activity (IC₅₀ 53.29 µg/mL) of breast cancer cell line (MCF-7). Additionally, larvicidal activity against mosquito vector Culex quinquefasciatus larvae delivered (LC₅₀-0.40, mg/L, and LC₉₀-15.83) significant mortality rate post treatment with synthesized AgNPs. Overall, the present research illustrates that the synthesized AgNPs have high biological potential and present a perfect contender in the pharmacological and mosquitocidal arena.

Green Synthesis of Zinc Oxide Nanocrystals Utilizing Origanum majorana Leaf Extract and Their Synergistic Patterns with Colistin against Multidrug-Resistant Bacterial Strains

There is a crucial necessity for the formulation of efficient antimicrobial agents owing to the increasing prevalence of hospital-acquired bacterial infections triggered by multidrug-resistant microbes that result in significant deaths and illnesses around the world. Hence, the current investigation examined the antibacterial proficiency of zinc oxide nanoparticles formulated utilizing the green route against bacterial strains that were resistant to multiple drugs. In addition, the synergistic antibacterial action of ZnO nanoparticles (ZnO NPs) combined with colistin was investigated against the tested microbial strains to determine the efficiency of the bioinspired ZnO nanoparticles in boosting the antibacterial proficiency of colistin antibiotic. Incidentally, the bioinspired ZnO nanoparticles were synthesized using water extract of Origanum majorana leaves and these nanomaterials were physicochemically characterized using different analytical techniques. The bioactivity of the synthesized nanomaterials against multidrug-resistant bacterial strains was appraised using the agar diffusion method. The biogenic ZnO NPs at a concentration of 100 μg/disk revealed a compelling antimicrobial efficacy against the tested strains, expressing the maximum antimicrobial action against Escherichia coli strain with clear zone diameter of 38.16 ± 0.18 mm. The remarkable antibacterial proficiency might be accredited to the tiny particle size of the bioformulated ZnO NPs of 12.467 ± 1.36 nm. The net charge of ZnO nanomaterials was −14.8 mV while XRD analysis confirmed their hexagonal wurtzite structure. Furthermore, the bioformulated ZnO NPs showed a promising synergistic potency with colistin demonstrating respective synergism proportions of 91.05, 79.07, 75.04, 75.25, 56.28 and 10.60% against E. coli, Klebsiella pneumoniae, Acinetobacter baumannii, Salmonella typhimurium, Enterobacter cloacae, and Pseudomonas aeruginosa, respectively. In conclusion, the water extract of O. majorana leaves mediated green formulation of zinc oxide nanoparticles with unique physicochemical characteristics and effective antibacterial proficiency against the examined drug-resistant bacterial strains. These nanomaterials could be used in the synthesis of effective antibacterial coatings to control hospital acquired infections caused by multidrug-resistant bacterial pathogens.

Biosynthesis of silver nanoparticles using three different fruit extracts: Characterization, formation mechanism and estrogen removal

Plant-mediated synthesis of silver nanoparticles (Ag NPs) is a green and economically viable method, which can offer numerous benefits over traditional chemical and physical methods. In this paper, three fruit extracts (tomato, orange, and grapefruit) served simultaneously as stabilizing and reducing agents during the biosynthesis of Ag NPs. The formation of Ag NPs, were monitored using the UV-visible absorption spectra of Ag NPs which exhibited three distinct bands centered at 439, 413, and 410 nm. SEM and TEM analysis indicated that these bands corresponded to three distinct spherical-shaped Ag NPs having average particle sizes of 73, 24, and 31 nm, respectively. XRD and EDS spectral analyses were used to verify the degree of crystallinity, nanostructure, and presence of Ag NPs. Advanced analysis using XPS, FTIR, and GC-MS indicated that the Ag NPs were coated with a variety of organic compounds including acids, aldehydes, esters, and ketones, indicating that fruit derived phytochemicals had a significant role in synthesis, and subsequently a mechanism of Ag NPs formation was proposed. The fabricated nanoparticles were also successfully used in Fenton-like oxidation for the environmental remediation of estrone and estriol, with removal efficiencies of 52.1 and 35.9%, respectively.

Enhancement of PCL/PLA Electrospun Nanocomposite Fibers Comprising Silver Nanoparticles Encapsulated with Thymus Vulgaris L. Molecules for Antibacterial and Anticancer Activities

Silver nanoparticles (AgNPs) have been recognized for their outstanding antibacterial activities, which are required for antibacterial coating materials in therapeutic applications. A bacterial-resistant electrospun nanofibrous mat made of polycaprolactone (PCL) in combination with polylactide acid (PLA) containing silver nanoparticles encapsulated with Thymus vulgaris L. (thyme) extract (eAgNPs) was fabricated in order to assess the potential of applicability in biomedical applications such as cancer treatment, wound healing, or surgical sutures. In the current study, PCL and PLA used as the basis polymers were blended with biosynthesized eAgNPs, pure AgNPs, and thyme extract (TE) to observe the effects of additives in terms of antibacterial and anticancer activity and morphologic, thermal, mechanical, biocompatibility, and biodegradability properties. The biological characteristics of fabricated electrospun nanofibrous mats were evaluated in vitro. Physicochemical characteristics of the nanofibrous mats were examined by UV-vis spectrophotometry, scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), mechanical tensile testing, X-ray diffraction (XRD), thermogravimetric examination (TGA), and water contact angles (WCAs). The results showed that a biodegradable nanofiber scaffold with a mean fiber diameter of 280 nm is morphologically homogeneous and highly hydrophobic, has higher tensile strength than PCL/PLA nanocomposite fiber, and is resistant to Escherichia coli and Staphylococcus aureus. The cytotoxic and anticancer properties of nanomaterials were defined using L929 and SK-MEL-30 cells. The developed material inhibited cell proliferation and led to apoptosis of cell lines. It can be suggested that the use of Thymus vulgaris L. extract-encapsulated silver nanoparticle-doped PCL/PLA nanofibers produced by the electrospinning method has the potential for cancer therapy in skin tumor cell lines.

Synthesis of silver nanoparticles using Eucommia ulmoides extract and their potential biological function in cosmetics

Silver nanoparticles (AgNPs) synthesized from plant extracts have recently emerged as a rapidly growing field with numerous applications in pharmaceutical and clinical contexts. The purpose of this research is to come up with a novel method for the biosynthesis of silver nanoparticles that use Eucommia ulmoides leaf extract as a reducing agent. The synthesis of AgNPs was confirmed using UV-vis spectroscopy, and the properties of AgNPs were characterized using Transmission Electron Microscope, Fourier Infrared Spectrometer, X-ray diffraction, Thermogravimetric Analysis, and Zeta potential. The results showed that the AgNPs exhibited a characteristic absorption peak at 430 nm, their diameter ranged from 4 nm to 52 nm, and C, O, and Cl elements, which might represent flavonoids and phenolic components absorbed on the surface of AgNPs. The zeta potential of AgNPs was found to be −30.5 mV, which indicates repulsion among AgNPs and they have good dispersion stability. AgNPs have been found to suppress the tyrosinase activity both in mushroom tyrosinase and A375 cells, as well as diminish ROS formation in HaCat cells. According to this study, AgNPs is a novel material that can enhance skin health by preventing melanin development.

Synergistic Antibacterial Activity of Green Synthesized Silver Nanomaterials with Colistin Antibiotic against Multidrug-Resistant Bacterial Pathogens

The high frequency of nosocomial bacterial infections caused by multidrug-resistant pathogens contributes to significant morbidity and mortality worldwide. As a result, finding effective antibacterial agents is of critical importance. Hence, the aim of the present study was to greenly synthesize silver nanoparticles (AgNPs) utilizing Salvia officinalis aqueous leaf extract. The biogenic AgNPs were characterized utilizing different physicochemical techniques such as energy-dispersive X-ray spectroscopy (EDX), ultraviolet-visible spectrophotometry (UV-Vis), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) analysis. Additionally, the synergistic antimicrobial effectiveness of the biosynthesized AgNPs with colistin antibiotic against multidrug-resistant bacterial strains was evaluated utilizing the standard disk diffusion assay. The bioformulated AgNPs revealed significant physicochemical features, such as a small particle size of 17.615 ± 1.24 nm and net zeta potential value of −16.2 mV. The elemental mapping of AgNPs revealed that silver was the main element, recording a relative mass percent of 83.16%, followed by carbon (9.51%), oxygen (5.80%), silicon (0.87%), and chloride (0.67%). The disc diffusion assay revealed that AgNPs showed antibacterial potency against different tested bacterial pathogens, recording the highest efficiency against the Escherichia coli strain with an inhibitory zone diameter of 37.86 ± 0.21 mm at an AgNPs concentration of 100 µg/disk. In addition, the antibacterial activity of AgNPs was significantly higher than that of colistin (p ≤ 0.05) against the multidrug resistant bacterial strain namely, Acinetobacter baumannii. The biosynthesized AgNPs revealed synergistic antibacterial activity with colistin antibiotic, demonstrating the highest synergistic percent against the A. baumannii strain (85.57%) followed by Enterobacter cloacae (53.63%), E. coli (35.76%), Klebsiella pneumoniae (35.19%), Salmonella typhimurium (33.06%), and Pseudomonas aeruginosa (13.75%). In conclusion, the biogenic AgNPs revealed unique physicochemical characteristics and significant antibacterial activities against different multidrug-resistant bacterial pathogens. Consequently, the potent synergistic effect of the AgNPs–colistin combination highlights the potential of utilizing this combination for fabrication of highly effective antibacterial coatings in intensive care units for successful control of the spread of nosocomial bacterial infections.

Fabrication of Silver Nanoparticles Using Cordyline fruticosa L. Leave Extract Endowing Silk Fibroin Modified Viscose Fabric with Durable Antibacterial Property

The current work presented a green synthetic route for the fabrication of silver nanoparticles obtained from aqueous solutions of silver nitrate using Cordyline fruticosa L. leaf extract (Col) as a reducing and capping agent for the first time. The bio-synthesized silver nanoparticles (AgCol) were investigated using UV-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA). The obtained data demonstrated that AgCol in spherical shape with an average size of 28.5 nm were highly crystalline and well capped by phytocompounds from the Col extract. Moreover, the bio-synthesized AgCol also exhibited the effective antibacterial activities against six pathogenic bacteria, including Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella enterica (S. enterica), Staphylococcus aureus (S. aureus), Bacillus cereus (B. cereus) and Enterococcus faecalis (E. faecalis). The AgCol were applied as an antibacterial finishing agent for viscose fabric using a pad-dry curing technique. The AgCol-treated viscose fabrics exhibited a good synergistic antimicrobial activity against E. coli and S. aureus bacteria. Furthermore, the silk fibroin regenerated from Bombyx mori cocoon waste was utilized as an ecofriendly binder for the immobilization of AgCol on the viscose fabric. Thus, the antimicrobial efficacy of the AgCol and fibroin modified viscose fabric still reached 99.99% against the tested bacteria, even after 30 washing cycles. The colorimetric property, morphology, elemental composition, and distribution of AgCol on the treated fabrics were investigated using several analysis tools, including colorimetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic absorption spectroscopy (AAS), Kjeldahl, and FTIR. Because of the excellent antimicrobial efficiency and laundering durability, as well as the green synthesis method, the AgCol and fibroin modified viscose fabric could be utilized as an antibacterial material in sportswear and medical textile applications.

Plant Extract-Based Synthesis of Metallic Nanomaterials, Their Applications, and Safety Concerns

Nanotechnology has attracted the attention of researchers from different scientific fields because of the escalated properties of nanomaterials compared with the properties of macromolecules. Nanomaterials can be prepared through different approaches involving physical and chemical methods. The development of nanomaterials through plant-based green chemistry approaches is more advantageous than other methods from the perspectives of environmental safety, animal, and human health. The biomolecules and metabolites of plants act as reducing and capping agents for the synthesis of metallic green nanomaterials. Plant-based synthesis is a preferred approach as it is not only cost-effective, easy, safe, clean, and eco-friendly but also provides pure nanomaterials in high yield. Since nanomaterials have antimicrobial and antioxidant potential, green nanomaterials synthesized from plants can be used for a variety of biomedical and environmental remediation applications. Past studies have focused mainly on the overall biogenic synthesis of individual or combinations of metallic nanomaterials and their oxides from different biological sources, including microorganisms and biomolecules. Moreover, from the viewpoint of biomedical applications, the literature is mainly focusing on synthetic nanomaterials. Herein, we discuss the extraction of green molecules and recent developments in the synthesis of different plant-based metallic nanomaterials, including silver, gold, platinum, palladium, copper, zinc, iron, and carbon. Apart from the biomedical applications of metallic nanomaterials, including antimicrobial, anticancer, diagnostic, drug delivery, tissue engineering, and regenerative medicine applications, their environmental remediation potential is also discussed. Furthermore, safety concerns and safety regulations pertaining to green nanomaterials are also discussed. This article is protected by copyright. All rights reserved.

Green Synthesis of Silver Nanoparticles Using Hypericum perforatum L. Aqueous Extract with the Evaluation of Its Antibacterial Activity against Clinical and Food Pathogens

The rapid development of nanotechnology and its applications in medicine has provided the perfect solution against a wide range of different microbes, especially antibiotic-resistant ones. In this study, a one-step approach was used in preparing silver nanoparticles (AgNPs) by mixing silver nitrate with hot Hypericum perforatum (St. John’s wort) aqueous extract under high stirring to prevent agglomeration. The formation of silver nanoparticles was monitored by continuous measurement of the surface plasma resonance spectra (UV-VIS). The effect of St. John’s wort aqueous extract on the formation of silver nanoparticles was evaluated and fully characterized by using different physicochemical techniques. The obtained silver nanoparticles were spherical, monodisperse, face-centered cubic (fcc) crystal structures, and the size ranges between 20 to 40 nm. They were covered with a capping layer of organic compounds considered as a nano dimension protective layer that prevents agglomeration and sedimentation. AgNPs revealed antibacterial activity against both tested Gram-positive and Gram-negative bacterial strains causing the formation of 13–32 mm inhibition zones with MIC 6.25–12.5 µg/mL; Escherichia coli strains were resistant to tested AgNPs. The specific growth rate of S. aureus was significantly reduced due to tested AgNPs at concentrations ≥½ MIC. AgNPs did not affect wound migration in fibroblast cell lines compared to control. Our results highlighted the potential use of AgNPs capped with plant extracts in the pharmaceutical and food industries to control bacterial pathogens’ growth; however, further studies are required to confirm their wound healing capability and their health impact must be critically evaluated.

Identification of Major Constituents of Hypericum perforatum L. Extracts in Syria by Development of a Rapid, Simple, and Reproducible HPLC-ESI-Q-TOF MS Analysis and Their Antioxidant Activities

Hypericum perforatum Linn (St. John's wort) is a popular and widespread medicine in Syria, which is used for a wide range of conditions, including gastrointestinal diseases, heart disease, skin diseases, and psychological disorders. This widespread use prompted us to identify the main compounds of this plant from Syria that are responsible for its medicinal properties, especially since its components differ between countries according to the nature of the soil, climate, and altitude. This is, to the best of our knowledge, the first report in which St. John's wort, a plant native to Syria, is extracted using different solvents and its most important compounds are identified. In this study, the dried above-ground parts, i.e., leaves, stem, petals, and flowers, were extracted using different solvents (water, ethanol, methanol, and acetone) and extraction protocols. By increasing the polarity of the solvent, higher yields were obtained, indicating that mainly hydrophobic compounds were extracted. Therefore, we conclude that extraction using the tea method or using a mixture of water and organic solvents resulted in higher yields compared with pure organic solvents or continuous boiling with water for long periods. The obtained extracts were analyzed using high-performance liquid chromatography equipped with a diode array detector (HPLC-DAD), coupled with UV-visible spectrophotometry at a full spectrum (200-800 nm). The HPLC spectra of the extracts were almost identical at three wavelengths (260 nm for phloroglucinols (hyperforin and derivates), 590 nm for naphthodianthrones (hypericins), and 350 nm for other flavonols, flavones, and caffeoylquinic acids), with differences observed only in the intensity of the peaks. This indicates that the same compounds were obtained using different solvents, but in different amounts. Five standards (chlorogenic acid, quercetin, quercitrin hydrate, hyperoside, and hypericin) were used, and a comparison with retention times and ultraviolet (UV) spectra reported in the literature was performed to identify 10 compounds in these extracts: hyperforin, adhyperforin, hypericin, rutin, quercetin, quercitrin, quercitrin hydrate, hyperoside, biapigenin, and chlorogenic acid. Although the European Pharmacopoeia still describes ultraviolet spectroscopy as a method for determining the quantity of Hyperici herba, interference from other metabolites can occur. Combined HPLC-DAD and electrospray ionization-mass spectrometry (LC-ESI-MS) in the positive mode have therefore also been used to confirm the presence of these compounds in the extracts by correlating known masses with the identified masses or through characteristic fragmentation patterns. Total phenolic contents of the extracts were determined by the Folin-Ciocalteu assay, and antioxidant activity was evaluated as free radical scavenging capacity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. The results indicate that the aqueous extracts prepared by the tea method gave the highest total phenols, while the pure organic solvents gave very low phenols. Also, the extracts that contain the largest amount of phenols gave lower IC₅₀ values or higher antioxidant activity than that of others.

Plant-Mediated Green Synthesis of Ag NPs and Their Possible Applications: A Critical Review

The potential applications of Ag NPs are exciting and beneficial in a variety of fields; however, there is less awareness of the new risks posed by inappropriate disposal of Ag NPs. The Ag NPs have medicinal, plasmonic, and catalytic properties. The Ag NPs can be prepared via physical, chemical, or biological routes, and the selection of any specific route depends largely on the end-use. The downside of a physical and chemical approach is that it requires a wide space, high temperature, high temperature for a longer time to preserve the thermal stability of synthesized Ag NPs, and the use of toxic chemicals. Although these methods produce nanoparticles with high purity and well-defined morphology, it is critical to develop cost-effective, energy-efficient, and facile route, such as green synthesis; it suggests the desirable use of renewable resources by avoiding the use of additional solvents and toxic reagents in order to achieve the ultimate goal. However, each method has its pros and cons. The synthesized Ag NPs obtained using the green approach have larger biocompatibility and are less toxic towards the biotic systems. However, identifying the phytoconstituents that are responsible for nanoparticle synthesis is difficult and has been reported as a suitable candidate for biological application. The concentration of the effective bioreducing phytoconstituents plays a crucial role in deciding the morphology of the nanoparticle. Besides these reaction times, temperature, pH, and concentration of silver salt are some of the key factors that determine the morphology. Hence, careful optimization in the methodology is required as different morphologies have different properties and usage. It is due to which the development of methods to prepare nanoparticles effectively using various plant extracts is gaining rapid momentum in recent days. To make sense of what involves in the bioreduction of silver salt and to isolate the secondary metabolites from plants are yet challenging. This review focuses on the contribution of plant-mediated Ag NPs in different applications and their toxicity in the aquatic system.

Synergistic effect of plant extract coupled silver nanoparticles in various therapeutic applications- present insights and bottlenecks

The phytocomponent conjugated silver nanoparticles (AgNPs) have been extensively explored for various therapeutic applications such as antimicrobial, antioxidant, anticancer, anti-inflammatory, antidiabetic and anticoagulant effects. The bio-conjugation of Ag-based nanomaterial with plant extracts reduces their toxicity to biological systems and enhances their therapeutic effectiveness. The diversity of phytochemicals or capping agents provided by the plant extracts and the small size and large surface area of AgNPs permits maximum adsorption of these capping agents onto their surfaces that further promote the therapeutic performance of phytoconjugated AgNPs in various biomedical applications. The mechanistic action involved in antimicrobial and anticancer functions of AgNPs is mainly dependent on the induction of reactive oxygen species (ROS) resulting in cellular apoptosis and necrosis. This review summarizes the recent studies of various plant extract assisted synthesis of AgNPs, potential biomedical applications with the possible mechanism of action and major shortcomings affecting their therapeutic efficacy.

Biosynthesis of Silver Nanoparticles and Their Applications in Harvesting Sunlight for Solar Thermal Generation

Silver (Ag) nanoparticles (NPs) have been synthesized through an easy, inexpensive, and ecofriendly method. Petroselinum crispum, parsley, leaf extract was utilized as a reducing, capping, and stabilizing agent, without using any hazardous chemical materials, for producing Ag NPs. The biosynthesized Ag NPs were characterized using different characterization techniques, namely UV-Vis, FT-IR spectroscopy, X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), dynamic light scattering (DLS), zeta potential, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) analysis to investigate the optical, thermal, structural, morphological, and chemical properties of the plant extract and the biosynthesized Ag NPs. After that, the biosynthesized Ag NPs were utilized in harvesting sunlight for solar thermal generation. Surface plasmon resonance (SPR) for the green synthesized Ag NPs with the dark color were adjusted at nearly 450 nm. Once the Ag NPs are excited at the SPR, a large amount of heat is released, which causes a change in the local refractive index surrounding the Ag NPs. The released heat from the Ag NPs under the solar irradiation at the precise wavelength of plasmon resonance significantly increased the temperature of the aqueous medium. Different percentages of Ag NPs were dispersed in water and then exposed to the sunlight to monitor the temperature of the suspension. It was found that the temperature of the aqueous medium reached its highest point when 0.3 wt. % of Ag NPs was utilized. This investigation is rare and unique, and it shows that utilizing a small amount of the biosynthesized Ag NPs can increase the temperature of the aqueous medium remarkably.