Biosynthesis, Characterization, and Bioactivities Evaluation of Silver and Gold Nanoparticles Mediated by the Roots of Chinese Herbal Angelica pubescens Maxim

Bioinspired and Green Synthesis of Silver Nanoparticles for Medical Applications: A Green Perspective

Silver nanoparticles (AgNPs) possess unmatched chemical, biological, and physical properties that make them unique compounds as antimicrobial, antifungal, antiviral, and anticancer agents. With the increasing drug resistance, AgNPs serve as promising entities for targeted drug therapy against several bacterial, fungal, and viral components. In addition, AgNPs also serve as successful anticancer agents against several cancers, including breast, prostate, and lung cancers. Several works in recent years have been done towards the development of AgNPs by using plant extracts like flowers, leaves, bark, root, stem, and whole plant parts. The green method of AgNP synthesis thus has several advantages over chemical and physical methods, especially the low cost of synthesis, no toxic byproducts, eco-friendly production pathways, can be easily regenerated, and the bio-reducing potential of plant derived nanoparticles. Furthermore, AgNPs are biocompatible and do not harm normally functioning human or host cells. This review provides an exhaustive overview and potential of green synthesized AgNPs that can be used as antimicrobial, antifungal, antiviral, and anticancer agents. After a brief introduction, we discussed the recent studies on the development of AgNPs from different plant extracts, including leaf parts, seeds, flowers, stems, bark, root, and whole plants. In the following section, we highlighted the different therapeutic actions of AgNPs against various bacteria, fungi, viruses, and cancers, including breast, prostate, and lung cancers. We then highlighted the general mechanism of action of AgNPs. The advantages of the green synthesis method over chemical and physical methods were then discussed in the article. Finally, we concluded the review by providing future perspectives on this promising field in nanotechnology.

Review green synthesis of silver nanoparticles by using plant extracts and their antimicrobial activity

Interest in the biosynthesis of nanoparticles has increased in the last era by researchers. Nanoparticles have several applications in different fields like optoelectronics, magnetic devices, drug delivery, and sensors. Nanoparticle synthesis by green methods is safe for the environment and should be explored and encouraged popularly since various plants' have the high extent to form these nanoparticles. Worldwide, UV spectroscopy, X-ray diffraction, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) besides Fourier Transform Infrared Spectroscopy (FTIR) are used in many ways for characterize nanoparticles. The most advantageous use of AgNPs is their great attribution to be used as antimicrobial agents. Finally, concept of AgNPs synthesis is deserved to be the modern technical and medical concern. The current review shows a complete comprehensive and analytical survey of the biosynthesis of AgNPs with a particular focus on their activities as antimicrobials and the possible theories of their effect on the microbial cell and all influenced secondary metabolites.

Biosynthesis Strategy of Gold Nanoparticles and Biofabrication of a Novel Amoxicillin Gold Nanodrug to Overcome the Resistance of Multidrug-Resistant Bacterial Pathogens MRSA and E. coli

The prevalence of multidrug-resistant (MDR) bacteria has recently increased dramatically, seriously endangering human health. Herein, amoxicillin (Amoxi)-conjugated gold nanoparticles (AuNPs) were created as a novel drug delivery system to overcome MDR bacteria. MDR bacteria were isolated from a variety of infection sources. Phenotype, biotype, and 16S rRNA gene analyses were used for isolate identification. Additionally, Juniperus excelsa was used for the production of AuNPs. The conjugation of AuNPs with Amoxi using sodium tri-polyphosphate (TPP) as a linker to produce Amoxi-TPP-AuNPs was studied. The AuNP and Amoxi-TPP-AuNP diameters ranged from 15.99 to 24.71 nm, with spherical and hexagonal shapes. A total of 83% of amoxicillin was released from Amoxi-TPP-AuNPs after 12 h, and after 3 days, 90% of the medication was released. The Amoxi-TPP-AuNPs exhibited superior antibacterial effectiveness against MRSA and MDR E. coli strains. Amoxi-TPP-AuNPs had MICs of 3.6-8 µg mL-1 against the tested bacteria. This is 37.5-83 fold higher compared to values reported in the literature. Amoxi-TPP-AuNPs exhibit a remarkable ability against MRSA and E. coli strains. These results demonstrate the applicability of Amoxi-TPP-AuNPs as a drug delivery system to improve therapeutic action.

Use of Euphorbia balsamifera Extract in Precursor Fabrication of Silver Nanoparticles for Efficient Removal of Bromocresol Green and Bromophenol Blue Toxic Dyes

Silver nanoparticles (Ag-NPs) are attracting great attention for their use in various applications, along with methods for their green and facile production. In this study, we present a new eco-friendly approach based on the use of Euphorbia balsamifera extract (EBE) in the green synthesis of silver nanoparticles (Ag-NPs), which are then applied as a reducing and stabilizing agent for the efficient removal of water-based reactive dyes such as bromocresol green (BCG) and bromophenol blue (BPB). The as-prepared Ag-NPs are quasi-spherical in shape, with an average diameter of 20-34 nm. Diverse characterization methods, including X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analysis, were used to analyze these Ag-NPs. The results reveal that water-soluble biomolecules in the Euphorbia balsamifera extract play an important role in the formation of the Ag-NPs. The removal of toxic dyes was studied under varied operational parameters such as Ag-NP dosage, initial dye concentration, pH, stirring time, and temperature. Under the optimum investigated conditions, nearly 99.12% and 97.25% of the bromocresol green and bromophenol blue dyes, respectively, were removed. Both BCG and BPB adsorption were found to adhere to pseudo-second-order kinetics (r₂² = 1 and 0.995) and fit the Langmuir isotherm models well (R₁² = 0.998 and 0.994), with maximal monolayer adsorption capacities of 20.40 and 41.03 mg/g, respectively. Their adsorption processes were observed to be intrinsically endothermic. The results confirm the potential of the Euphorbia balsamifera extract as a low-cost, nontoxic, and eco-friendly natural resource for the synthesis of Ag-NPs that may be useful in the remediation of hazardous dye-contaminated water sources.

Biosynthesis of Gold and Silver Nanoparticles Using Phytochemical Compounds

Gold and silver nanoparticles are nanoparticles that have been widely used in various fields and have shown good benefits. The method of nanoparticle biosynthesis utilizing plant extracts, also known as green synthesis, has become a promising method considering the advantages it has compared to other synthesis methods. This review aims to give an overview of the phytochemical compounds in plants used in the synthesis of gold and silver nanoparticles, the nanoparticle properties produced using plant extracts based on the concentration and structure of phytochemical compounds, and their applications. Phytochemical compounds play an important role as reducing agents and stabilizers in the stages of the synthesis of nanoparticles. Polyphenol compounds, reducing sugars, and proteins are the main phytochemical compounds that are responsible for the synthesis of gold and silver nanoparticles. The concentration of phytochemical compounds affects the physical properties, stability, and activity of nanoparticles. This is important to know to be able to overcome limitations in controlling the physical properties of the nanoparticles produced. Based on structure, the phytochemical compounds that have ortho-substituted hydroxyl result in a smaller size and well-defined shape, which can lead to greater activity and stability. Furthermore, the optimal condition of the biosynthesis process is required to gain a successful reaction that includes setting the metal ion concentration, temperature, reaction time, and pH.

Green Synthesis of Silver Nanoparticles Using Salvia verticillata and Filipendula ulmaria Extracts: Optimization of Synthesis, Biological Activities, and Catalytic Properties

The study's objective was to obtain silver nanoparticles (SVAgNP and FUAgNP) using aqueous extracts of Salvia verticillata and Filipendula ulmaria. The optimal conditions for nanoparticle synthesis were determined and obtained; nanoparticles were then characterized using UV-Vis, Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS). SVAgNP and FUAgNP possessed a crystalline structure with 48.42% and 60.41% silver weight, respectively. The highest percentage of nanoparticles in the solution had a diameter between 40 and 70 nm. In DPPH˙ and ABTS˙⁺ methods, FUAgNP (IC₅₀ 15.82 and 59.85 µg/mL, respectively) demonstrated a higher antioxidant capacity than SVAgNP (IC₅₀ 73.47 and 79.49 µg/mL, respectively). Obtained nanoparticles also showed pronounced antibacterial activity (MIC ˂ 39.1 µg/mL for most of the tested bacteria), as well as high biocompatibility with the human fibroblast cell line MRC-5 and significant cytotoxicity on some cancer cell lines, especially on the human colon cancer HCT-116 cells (IC₅₀ 31.50 and 66.51 µg/mL for SVAgNP and FUAgNP, respectively). The nanoparticles demonstrated high catalytic effectiveness in degrading Congo red dye with NaBH₄. The results showed a rapid and low-cost methodology for the synthesis of AgNPs using S. verticillata and F. ulmaria with promising biological potential.

Synthesis and characterization of plant extracted silver nanoparticles and advances in dental implant applications

Dental implantology has always emphasized silver nanoparticles (AgNPs) for various applications due to their biocompatibility, antibacterial activity, and increased surface volume ratio offered by these particles. It is utilized to a large extent in the dental implant industry as a surface modification, biocompatible constituent and composite material. AgNPs may be produced inexpensively, sustainably, and environmentally responsibly by utilizing technologies that extract the plant material. The phytochemical components that are contained in plants make them a better, non-toxic, and more cost-effective alternative to both physical and chemical approaches. Because the size and shape of AgNP depend on their synthesis method and technique, and because the efficacy and toxicity of AgNP depend on both size and shape, synthesis methods and techniques have recently become the focus of a significant amount of research attention. In this review, we discussed Plant Extracted Ag-NP's whose sizes range up to 100nm. This review also focuses on recent research advancements in the Plant Extracted synthesis of AgNPs, as well as their characterization methodologies, current obstacles, future possibilities, and applications in dental implantology.

Green synthesized gold nanoparticles from Pseudobulbus Cremastrae seu Pleiones show efficacy against hepatic carcinoma potentially through immunoregulation

Nanobiotechnology, the interface between biology and nanotechnology, has recently emerged in full bloom in the medical field due to its minimal side-effects and high efficiency. To broaden the application of nanobiotechnology, we composed gold nanoparticles from the extract of Pseudobulbus Cremastrae seu Pleiones (PCSP) using an efficient and green procedure. The biosynthesized Au nanoparticles containing PCSP (PCSP-AuNPs) were characterized by UV-vis spectroscopic, transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and Energy Dispersive X-ray (EDAX). After verifying the stability of PCSP-AuNPs, we detected its biosafety and immune-modulatory effects on RAW264.7 in vitro using NO assay, ELISA (TNF-α, IL-12p70, and IL-1β), and CCK-8 test. Furthermore, we examined the direct in vitro effects of PCSP-AuNPs on hepatocellular carcinomas (HCCs). Finally, we evaluated the immune regulation of PCSP-AuNPs using a mouse model with H22-tumor by testing the index of immune organs, splenic lymphocyte proliferation, cytokines levels (TNF-α and IL-10), and the CD4+/CD8+ cell ratio in the peripheral blood. Immunohistochemical analyses including H&E and PCNA staining were performed to investigate the anti-cancer efficacy and biocompatibility of PCSP-AuNPs. We found that PCSP-AuNPs not just possessed low toxicity, but also improved the immune-mediated antitumor response as compared to PCSP alone, suggesting its potential as a novel and efficient drug for liver cancer therapy.

Biologically synthesis of gold nanoparticles using Cirsium japonicum var. maackii extract and the study of anti-cancer properties on AGS gastric cancer cells

Plant extract-mediated synthesis of metal nanoparticles (NPs) is an eco-friendly and cost-effective biosynthesis method that is more suitable for biological applications than chemical ones. We prepared novel gold NPs (AuNPs), Cirsium japonicum mediated-AuNPs (CJ-AuNPs), using a biosynthetic process involving Cirsium japonicum (Herba Cirsii, CJ) ethanol extract. The physicochemical properties of CJ-AuNPs were characterized using spectrometric and microscopic analyses. The in vitro stability of CJ-AuNPs was studied for 3 months. Moreover, the selective human gastric adenocarcinoma (AGS) cell killing ability of CJ-AuNPs was verified in cancer and normal cells. An in vitro study revealed that CJ-AuNPs trigger oxidative stress and iron-dependent ferroptosis in AGS cells. Mechanistically, CJ-AuNPs induced mitochondrial reactive oxygen species (ROS), Fe²⁺, and lipid peroxidation accumulation, and mitochondrial damage by destroying the glutathione peroxidase-4 (GPX4)-dependent antioxidant capacity. Furthermore, in a xenograft mouse model implanted with AGS cells, treatment with 2.5, 5, and 10 mg/kg CJ-AuNPs for 16 days reduced tumor xenograft growth in a dose dependent manner in vivo without systemic toxicity. These results demonstrate that CJ-AuNPs exert anticancer effects in vitro and in vivo by inducing ferroptosis-mediated cancer cell death. This study, based on green-synthesized nanodrug-induced ferroptosis, provides new insight into potential developments in cancer therapies.

Structural characterization and antibacterial activity of silver nanoparticles synthesized using a low-molecular-weight Royal Jelly extract

In recent years silver nanoparticles (Ag NPs) gained increased and widespread applications in various fields of industry, technology, and medicine. This study describes the green synthesis of silver nanoparticles (Ag NPs) applying a low-molecular-weight fraction (LMF) of Royal Jelly, the nanoparticle characterization, and particularly their antibacterial activity. The optical properties of NPs, characterized by UV–Vis absorption spectroscopy, showed a peak at ~ 430 nm. The hydrodynamic radius and concentration were determined by complementary dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The particle morphology was investigated using transmission electron microscopy (TEM), and the crystallinity of the silver was confirmed by X-ray diffraction (XRD). The antibacterial activities were evaluated utilizing Gram-negative and Gram-positive bacteria and colony counting assays. The growth inhibition curve method was applied to obtain information about the corresponding minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) required. Obtained results showed that (i) the sizes of Ag NPs are increasing within the increase of silver ion precursor concentration, (ii) DLS, in agreement with NTA, showed that most particles have dimensions in the range of 50–100 nm; (iii) E. coli was more susceptible to all Ag NP samples compared to B. subtilis.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.

Green synthesis and characterization of gold nanoparticles from Pholiota adiposa and their anticancer effects on hepatic carcinoma

Gold nanoparticles (AuNPs) were successfully fabricated by Pholiota adiposa polysaccharide (PAP-1a) without employing any other chemicals. The physical and chemical properties of PAP-AuNPs were determined using transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDXR), Fourier-transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM). In an attempt to analyze the immune regulation, antitumor effect, and biological safety, the production of NO and TNF-α, IL-12p70, and IL-1β from RAW264.7 as well as the proliferation of RAW264.7 were detected in vitro. Flow cytometry was conducted to determine the ratio of the CD4⁺/CD8⁺ cell in peripheral blood and immunohistochemical analysis involving hematoxylin and eosin (H&E) and proliferating cell nuclear antigen (PCNA) staining were conducted in vivo. The results of this study showed that PAP-AuNPs had a significantly improved immune regulation and anti-tumor effect in comparison to PAP-1a alone. PAP-AuNPs showed no toxicity both in vivo and in vitro. This study demonstrates a useful application of PAP-AuNPs as a novel nanomedicine for hepatic carcinoma.

Gold Nanoparticles Green-Synthesized by the Suaeda japonica Leaf Extract and Screening of Anti-Inflammatory Activities on RAW 267.4 Macrophages

Biosynthesis of gold nanoparticles from medicinal plants has become a modern strategy in biomedical research based on their exclusive properties, including specific targeting, lower toxicity, and biocompatibility. In this study, gold nanoparticles, reduced by the Suaeda japonica leaf extract, were promptly validated by UV–visible (UV–Vis) spectroscopy at 548 nm. No additional reducing agents were needed in this kind of a reduction reaction, which provided evidence of green synthesis. Dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), field-emission transmission electron microscopy (FE-TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) analyses were used to illustrate the nanoscale characterization of S. japonica gold nanoparticles (Sj-AuNps). Furthermore, the cytotoxicity effect of Sj-AuNps against the RAW 264.7 cell line was determined by performing an MTT assay. We also investigated Sj-AuNps’ anti-inflammatory properties in LPS-induced murine macrophages. These nanoparticles reduced the generation of nitric oxide (NO) and prostaglandin E2 (PGE2) and repressed the expression of the LPS-stimulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes. This study presents a significant biomedical application of S. japonica AuNps. The anti-inflammatory capabilities of Sj-AuNps underline their potential as possible options for suppressing inflammation-mediated diseases.

Green Synthesis and Potential Antibacterial Applications of Bioactive Silver Nanoparticles: A Review

Green synthesis of silver nanoparticles (AgNPs) using biological resources is the most facile, economical, rapid, and environmentally friendly method that mitigates the drawbacks of chemical and physical methods. Various biological resources such as plants and their different parts, bacteria, fungi, algae, etc. could be utilized for the green synthesis of bioactive AgNPs. In recent years, several green approaches for non-toxic, rapid, and facile synthesis of AgNPs using biological resources have been reported. Plant extract contains various biomolecules, including flavonoids, terpenoids, alkaloids, phenolic compounds, and vitamins that act as reducing and capping agents during the biosynthesis process. Similarly, microorganisms produce different primary and secondary metabolites that play a crucial role as reducing and capping agents during synthesis. Biosynthesized AgNPs have gained significant attention from the researchers because of their potential applications in different fields of biomedical science. The widest application of AgNPs is their bactericidal activity. Due to the emergence of multidrug-resistant microorganisms, researchers are exploring the therapeutic abilities of AgNPs as potential antibacterial agents. Already, various reports have suggested that biosynthesized AgNPs have exhibited significant antibacterial action against numerous human pathogens. Because of their small size and large surface area, AgNPs have the ability to easily penetrate bacterial cell walls, damage cell membranes, produce reactive oxygen species, and interfere with DNA replication as well as protein synthesis, and result in cell death. This paper provides an overview of the green, facile, and rapid synthesis of AgNPs using biological resources and antibacterial use of biosynthesized AgNPs, highlighting their antibacterial mechanisms.

Hybridization of green synthesized silver nanoparticles with poly(ethylene glycol) methacrylate and their biomedical applications

In the present research, a rapid, simple and efficient green method is used for the incorporation of silver nanoparticles (AgNPs) into poly(ethylene glycol) methacrylate (PEGMA) to create biocatalysts with excellent properties for pharmaceutical purpose. In the first phase, Caralluma tuberculata capped AgNPs (Ca-AgNPs) were prepared using green synthetic approach and in the second phase Caralluma tuberculata capped AgNPs were hybridized with poly(ethylene glycol) methacrylate to form PEGMA-AgNPs. Both the virgin (naked or uncapped) and polymer-capped materials were characterized spectroscopically and their results were compared. Fourier transform infrared spectroscopy showed no new peak after the capping procedure, showing that only physical interactions takes place during capping. After PEGMA capping, the spectra of the AgNPs red shifted (from 450 nm to 520 nm) and the overall particle size of AgNPs increased. Catalytic activity of the nanoparticles and hybrid system were tested by choosing the catalytic reduction of 4-nitrophenol (4-NP) as a model reaction. Both synthesized NPs and polymer capped NPs exhibits catalytic activity for the reduction of 4-NP to 4-aminophenol. The polymer hybrid exhibits remarkable antiproliferative, antioxidant, cytotoxic, antidiabetic and antileishmanial activities.

Gold Nanoparticles: Biosynthesis and Potential of Biomedical Application

Gold nanoparticles (AuNPs) are extremely promising objects for solving a wide range of biomedical problems. The gold nanoparticles production by biological method ("green synthesis") is eco-friendly and allows minimization of the amount of harmful chemical and toxic byproducts. This review is devoted to the AuNPs biosynthesis peculiarities using various living organisms (bacteria, fungi, algae, and plants). The participation of various biomolecules in the AuNPs synthesis and the influence of size, shapes, and capping agents on the functionalities are described. The proposed action mechanisms on target cells are highlighted. The biological activities of "green" AuNPs (antimicrobial, anticancer, antiviral, etc.) and the possibilities of their further biomedical application are also discussed.

Multifunctional 3D cationic starch/nanofibrillated cellulose/silver nanoparticles nanocomposite cryogel: Synthesis, adsorption, and antibacterial characteristics

We report a new 3D nanocomposite cryogel combines the advantages of cationic starch (Cs), nanofibrillated cellulose (NFC) and silver nanoparticles (Ag NPs). Cs was the main component of the cryogel while NFC was used as a filling agent to enhance the mechanical properties of the produced cryogel. Both Cs and NFC endow the cryogel with adsorption properties while Ag NPs enhances its antibacterial properties. Ag NPs was green synthesized with the aid of microwave radiation using NFC as reducing and stabilizing agent. The prepared Ag particles were free of impurities with sizes <10 nm and good stability in solution. Two different concentrations of the prepared Ag NPs were added to a mixture of Cs and NFC and subjected to freeze drying to get porous cryogel (3D microstructure). The Ag NPs free cryogel has highly porosity smooth surface with large surface area. Adding Ag NPs decreased these features and increased the 3D roughness. Optimum adsorption of reactive blue 49 was observed after 30 min of contact with 1.5 g/L of the cryogel at pH 1. The adsorption kinetics and isotherm were best described by the pseudo-first-order and Freundlich equations, respectively. All prepared cryogels have notable antibacterial properties that were significantly improved by adding Ag NPs. Overall, the new 3D composite cryogel can efficiently remove dyes and bacteria from wastewater.

Biomedical Applications of Chinese Herb-Synthesized Silver Nanoparticles by Phytonanotechnology

Recent advances in nanotechnology have opened up new avenues for the controlled synthesis of nanoparticles for biomedical and pharmaceutical applications. Chinese herbal medicine is a natural gift to humanity, and it has long been used as an antibacterial and anticancer agent. This study will highlight recent developments in the phytonanotechnological synthesis of Chinese herbal medicines to utilize their bioactive components in biomedical and therapeutic applications. Biologically synthesized silver nanoparticles (AgNPs) have emerged as a promising alternative to chemical and physical approaches for various biomedical applications. The comprehensive rationale of combinational or synergistic effects of Chinese herb-based AgNPs synthesis was investigated with superior physicochemical and biological properties, and their biomedical applications, including antimicrobial and anticancer activity and wound healing properties. AgNPs can damage the cell ultrastructure by triggering apoptosis, which includes the formation of reactive oxygen species (ROS), DNA disintegration, protein inactivation, and the regulation of various signaling pathways. However, the anticancer mechanism of Chinese herbal medicine-based AgNPs is more complicated due to the potential toxicity of AgNPs. Further in-depth studies are required to address Chinese herbs' various bioactive components and AgNPs as a synergistic approach to combat antimicrobial resistance, therapeutic efficiency of drug delivery, and control and prevention of newly emerged diseases.

Antimicrobial, antioxidant and anticancer activities of gold nanoparticles green synthesized using Mangifera indica seed aqueous extract

In this study, gold nanoparticles (AuNPs) were synthesised using seed extract of mango (Mangifera indica) which is considered as waste and generally thrown away into the environment. The bioactive molecules in the seed act as reducing agent to synthesise AuNPs without using any external agent. The characterisation of green synthesised AuNPs was done using various spectroscopic techniques. Visual colour change from colourless to ruby red colour confirmed the formation of AuNPs which was further confirmed by maximum absorption peak at 550 nm by UV-spectra. Crystalline nature was confirmed by XRD technique while round, triangle and irregular shape and 19.45 nm size was confirmed by TEM and SAED analysis. FTIR analysis confirmed the presence of alcohol or phenol, carboxylic acid, ketones, amines, aromatic amines, aliphatic amines, alkyl halides and alkynes in M. indica seed which were responsible for the reduction of gold to AuNPs. The green synthesised AuNPs were evaluated for their antimicrobial, antioxidant and cytotoxic potential. They showed moderate antibacterial, cytotoxic and dose-dependent antioxidant activity. Seeds of M. indica instead of discarding can be successfully utilised for AuNPs synthesis which can be used as a natural source of antimicrobial, antioxidant and anticancer agent. Highlights Green synthesis of gold nanoparticles (AuNPs) from fruit (Mangifera indica) waste (seed). Characterisation using various spectroscopic techniques: UV-Vis spectroscopy, Zeta potential, FTIR, XRD and TEM analysis. Synthesized AuNPs were round, triangle and irregular in shape and 19.45 nm in size. Antimicrobial activity of AuNPs against 14 microorganisms. Antioxidant activity of AuNPs in terms of DPPH, SO and ABTS. Cytotoxic activity against HeLa, MCF-7 and fibroblast normal cell lines.

Biosynthesis of gold nanoparticles using Nigella sativa and Curtobacterium proimmune K3 and evaluation of their anticancer activity

In recent times, the development of functionalized nanoparticle methodology for biomedical applications has become a major challenge. In the present study, we prepared a novel gold nanoparticle (AuNP), named Curto-Cumin AuNP (CC-AuNP), using the biosynthetic process involving Nigella sativa (black cumin) seed extract and membrane vesicles isolated from the novel probiotic strain, Curtobacterium proimmune K3. Various spectrometric and microscopic analyses were performed to characterize the physicochemical properties of the nanoparticles. CC-AuNP exhibited significant cytotoxicity against human gastric adenocarcinoma (AGS) cells but not against normal cells. The toxic effects of the nanoparticles were associated with the excessive production of reactive oxygen species (ROS) in damaged mitochondria. Further, we investigated the molecular mechanisms underlying the cytotoxic effect of CC-AuNP. Results showed that except for B cell lymphoma 2 (Bcl-2), the intracellular apoptotic signaling molecules, such as p53, Bcl-associated X protein (Bax), and Caspase 9/Caspase 3 were significantly upregulated in AGS cells. ROS production and alterations in mitochondrial membrane potential were observed in AGS cells treated with CC-AuNP. The activation of autophagy flux-related biomarkers, such as LC3b/a, Beclin-1, p62, and Caspase 8, was confirmed by qPCR and western blotting. Autophagy pathway was suppressed in CC-AuNP-treated AGS cells and could not proceed further to the mature state. This was confirmed by the evaluation of both apoptosis and autophagy signaling pathways using autophagy-induced AGS cells treated with rapamycin, a well-studied autophagy activator. Overall, our results showed that CC-AuNP upregulates apoptotic signaling and suppresses the autophagy-related signaling pathway, and thus has potential as an anticancer agent. To our knowledge, the present study is the first to demonstrate that CC-AuNP may serve as novel therapeutic agent against gastric cancer. Furthermore, our study provides preliminary data which can be used to develop novel anticancer candidates and understand their anticancer mechanisms, and seems to be a good starting point for the development of alternative medications based on CC-AuNP.

Hydrogel with silver nanoparticles synthesized by Mimosa tenuiflora for second-degree burns treatment

In this work we use Mimosa tenuiflora (MtE) extracts as reducing agents to synthesize silver nanoparticles (AgMt NPs) which were characterized by DPPH and Total Polyphenols Assays, UV-visible, X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Thermogravimetric analysis (TGA). AgMt NPs possess average sizes of 21 nm and fcc crystalline structure, it was also confirmed that the MtE is present in the AgMt NPs even after the cleaning protocol applied. Subsequently, carbopol hydrogels were made and the MtE and the synthesized AgMt NPs were dispersed in different gels (MtE-G and AgMt NPs-G, respectively) at 100 µg/g concentration. The gels were characterized by UV-Vis, IR, and rheology. Antimicrobial tests were performed using Staphylococcus aureus and Escherichia coli. Burn wound healing was evaluated in a second-degree burn injury on a Wistar rats model for 14 days and additional skin biopsies were examined with histopathological analysis. Gel with commercial silver nanoparticles (Ag NPs) was prepared and employed as a control on the biological assays. Hydrogel system containing silver nanoparticles synthesized with Mimosa tenuiflora (AgMt NPs-G) is a promising therapeutic strategy for burn wound healing, this due to bactericidal and anti-inflammatory effects, which promotes a more effective recovery (in percentage terms) by damaged area.

Green synthesis of gold nanoparticles from Dendrobium officinale and its anticancer effect on liver cancer

A novel gold nanoparticle (Do-AuNP) was successfully synthesized from water extracts of traditional Chinese medicine Dendrobium officinale (DO) without using any extra chemicals regents. The physicochemical properties of Do-AuNPs were analyzed by transmission electron microscopy, dynamic light scattering, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The amount of DO extract on the AuNPs was about 13%. In order to evaluate the anti-tumor efficiency and biosafety, the inhibitory rate of HepG2 cells and survival rate of L02 cells were performed in vitro, and the immunohistochemical analysis of H&E, Ki-67, and TUNEL staining were conducted in vivo. Our results demonstrated that Do-AuNP had better anti-tumor efficiency compared with DO extraction alone without increasing toxicity in vivo and in vitro. The present study provides useful information for Do-AuNP as a new nanomedicine for liver cancer.

Biosynthetic gold nanoparticles of Hibiscus syriacus L. callus potentiates anti-inflammation efficacy via an autophagy-dependent mechanism

Biological applications of gold nanoparticles (AuNps) have potentially explored an efficient agent attributed to their biocompatibility and high efficiency in drug delivery. Our study applied an extract of Hibiscus syriacus L. callus (HCE) with a pioneer implementation on the induction of mass production. Bioactive compounds present in HCE were identified by Gas chromatography-mass spectrometry (GC-MS) and Liquid chromatography MS (LC-MS), wherein, the Denatonium was exclusively identifiable in HCE. Next, AuNps were synthesized and optimized using HCE (HCE-AuNps), and the comparison was conducted to evaluate the anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated macrophages. As per result, HCE-AuNps was reported to show a prominent reduction of pro-inflammatory cytokines and renovate the mitochondrial function through restoring the mitochondrial membrane potential changes, decreasing reactive oxygen species (ROS) accumulation, and recovering ATP contents, respectively. Furthermore, the immunoblotting of LC3b/a accumulation, and p62 rapid degradation revealed that HCE-AuNps could induce the autophagy as an intracellular response to reinforce alleviation of pro-inflammatory cytokines and mitochondria dysfunction. Besides, 740 Y-P (PI3K agonist) was used to verify that inhibiting autophagy could partially reverse HCE-AuNps suppressed mitochondrial dysfunction, and thus exacerbated inflammation, supporting a causal role for autophagy in the anti-inflammatory effect of HCE-AuNps. Taken together, we strongly anticipate that HCE-AuNps would act as a potential autophagy inducer for LPS-triggered macrophage's inflammation, providing a novel insight for biosynthetic nanoparticles in the treatment of mitochondria dysfunction and inflammation related diseases.

Bioremediation and pharmacological applications of gold nanoparticles synthesized from plant materials

Nanotechnology and nanoscience are gaining remarkable attention in this era due to their distinctive properties and multi applications. Gold nanoparticles (AuNPs) is one of the most relevant metal nanoparticles with enormous applications in various field of research and industries. The demand for AuNPs is increasing rapidly. Extensive awareness has been allotted to the development of novel approaches for the synthesis of AuNPs with quality morphological properties using biological sources due to the limitations associated with the chemical and physical methods. Several factors such as contact time, temperature, pH of solution media, concentration of gold precursors and volume of plant extract influences the synthesis, characterization and applications of AuNPs. Characterization of synthesized AuNPs is important in evaluating the morphological properties of AuNPs since the morphological properties of AuNPs affect their potential use in various applications. This review highlights various methods of synthesizing AuNPs, parameters influencing the biosynthesis of AuNPs from plant extract, several techniques used for AuNPs characterization and their potential in bioremediation and biomedical applications.

Update on Nanoparticle-Based Drug Delivery System for Anti-inflammatory Treatment

Nanobiotechnology plays an important role in drug delivery, and various kinds of nanoparticles have demonstrated new properties, which may provide opportunities in clinical treatment. Nanoparticle-mediated drug delivery systems have been used in anti-inflammatory therapies. Diseases, such as inflammatory bowel disease, rheumatoid arthritis, and osteoarthritis have been widely impacted by the pathogenesis of inflammation. Efficient delivery of anti-inflammatory drugs can reduce medical dosage and improve therapeutic effect. In this review, we discuss nanoparticles with potential anti-inflammatory activity, and we present a future perspective regarding the application of nanomedicine in inflammatory diseases.

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.

Anticancer activity of gold nanobioconjugates synthesized from Elephantopus scaber (linn.) leaf extract

Introduction

Medicinal plants are the major natural resources for the treatment of human ailments including cancer therapy. The current cancer treatments such as surgery, radiation, and chemotherapy affect normal cells too. Thus, treatments like synthesized nanoscale particles using plant extracts have proven to be potential anticancer agent.

Aim of the Study

We hypothesize that the gold nanoparticles (AuNPs) synthesized using Elephantopus scaber hydro-methanolic extract may have anti-cancer activity along with their synergistic counterparts with adriamycin (ADR) on human breast cancer MCF-7: human breast cancer (A-549), human oral cancer (squamous cell carcinoma [SCC]-40), and COLO-205: human colon cancer cell lines.

Materials and Methods

The phytosynthesized AuNPs were characterized for ultraviolet-visible (UV-Vis) spectroscopy, nanoparticle tracking analysis (NTA), X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) analysis. The anticancer ability of the AuNPs against human MCF-7, A-549, SCC-40, and COLO-205 through sulforhodamine B assay has been studied.

Results

The synthesis of AuNPs was confirmed with the UV-Vis spectrophotometer with a peak at 540 nm. The FTIR analysis showed polyphenolic groups were major found to be the reduction and capping agent for AuNPs. According to the results obtained, AuNPs showed good anti-proliferative activity with GI50 <10 μg/ml on MCF-7 cancer cell line. The synergistic effect of AuNPs + ADR was even better for all the four cell lines than that of the AuNPs alone.

Conclusion

The green synthesis of AuNPs is a simple, eco-friendly, and cost-effective method with dominantly spherical morphology ranging from 20 to 40 nm confirmed by NTA and TEM analysis. The study reveals the potent therapeutic value of the AuNPs.

Metal-Based Nanoparticles as Antimicrobial Agents: An Overview

Metal-based nanoparticles have been extensively investigated for a set of biomedical applications. According to the World Health Organization, in addition to their reduced size and selectivity for bacteria, metal-based nanoparticles have also proved to be effective against pathogens listed as a priority. Metal-based nanoparticles are known to have non-specific bacterial toxicity mechanisms (they do not bind to a specific receptor in the bacterial cell) which not only makes the development of resistance by bacteria difficult, but also broadens the spectrum of antibacterial activity. As a result, a large majority of metal-based nanoparticles efficacy studies performed so far have shown promising results in both Gram-positive and Gram-negative bacteria. The aim of this review has been a comprehensive discussion of the state of the art on the use of the most relevant types of metal nanoparticles employed as antimicrobial agents. A special emphasis to silver nanoparticles is given, while others (e.g., gold, zinc oxide, copper, and copper oxide nanoparticles) commonly used in antibiotherapy are also reviewed. The novelty of this review relies on the comparative discussion of the different types of metal nanoparticles, their production methods, physicochemical characterization, and pharmacokinetics together with the toxicological risk encountered with the use of different types of nanoparticles as antimicrobial agents. Their added-value in the development of alternative, more effective antibiotics against multi-resistant Gram-negative bacteria has been highlighted.

Constructing a Core Collection of the Medicinal Plant Angelica biserrata Using Genetic and Metabolic Data

Angelica biserrata is an important medicinal plant in Chinese traditional medicine. Its roots, which are known as Duhuo in Chinese, are broadly applied to treat inflammation, arthritis, and headache. With increasing market demand, the wild resources of A. biserrata have been overexploited, and conservation, assessment of genetic resources and breeding for this species is needed. Here, we sequenced the transcriptome of A. biserrata and developed simple sequence repeat (SSR) markers from it to construct a core collection based on 208 samples collected from Changyang-related regions. A total of 132 alleles were obtained for 17 SSR loci used with the polymorphic information content (PIC) ranging from 0.44 to 0.83. Abundant genetic diversity was inferred by Shannon's information index (1.51), observed (0.57) and expected heterozygosity (0.72). The clustering analysis resulted into two sample groups and analysis of molecular variance (AMOVA) showed only 6% genetic variation existed among populations. A further metabolic analysis of these samples revealed the main coumarin contents, such as osthole and columbianadin. According to the genetic and metabolic data, we adopted the least distance stepwise sampling strategy to construct seven preliminary core collections, of which the 20CC collection, which possessed 42 A. biserrata individuals accounting for 90.20% of the genetic diversity of the original germplasm, represented the best core collection. This study will contribute to the conservation and management of A. biserrata wild germplasm resources and provide a material basis for future selection and breeding of this medicinal plant.

Synthesis of a Zinc Oxide Nanoflower Photocatalyst from Sea Buckthorn Fruit for Degradation of Industrial Dyes in Wastewater Treatment

: Green synthesis of ZnO nanoparticles has attracted research attention as a sustainable method of avoiding the destructive effect of chemicals. We synthesized a flower-shaped zinc oxide (ZnO) nanoflower (NF) from sea buckthorn fruit (SBT) by co-precipitation and characterized it using X-ray powder diffraction (XRD), X-ray photo electronic microscopy (XPS), photoluminescence (PL), field emission transmission electron microscopy (FE-TEM), and Fourier-transform infrared (FT-IR) spectroscopy. The ability of the ZnO/NF to degrade cationic and anionic dyes, including malachite green (MG), Congo red (CR), methylene blue (MB), and eosin Y (EY), under ultraviolet illumination was studied. The photocatalyst degraded approximately 99% of the MG, MB, CR and EY dyes within 70, 70, 80, and 90 min of contact time, respectively, at a dye concentration of 15 mg/L, 5 mg/L, SBT-ZnO/NF degraded 100% of the MG, MB, CR and EY dyes within 23, 25, 28, and 30 min, respectively. The results indicate that SBT-ZnO/NFs as synthesized is an inexpensive, non-toxic, rapid, and reusable photocatalyst that can play an enhanced role in wastewater treatment.

Synthesis of Gold Nanoparticles Using Mimosa tenuiflora Extract, Assessments of Cytotoxicity, Cellular Uptake, and Catalysis

Synthesis of gold nanoparticles (AuNPs) with plant extracts has gained great interest in the field of biomedicine due to its wide variety of health applications. In the present work, AuNPs were synthesized with Mimosa tenuiflora (Mt) bark extract at different metallic precursor concentrations. Mt extract was obtained by mixing the tree bark in ethanol-water. The antioxidant capacity of extract was evaluated using 2,2-diphenyl-1-picrylhydrazyl and total polyphenol assay. AuNPs were characterized by transmission electron microscopy, X-ray diffraction, UV-Vis and Fourier transform infrared spectroscopy, and X-ray photoelectron spectrometry for functional group determination onto their surface. AuMt (colloids formed by AuNPs and molecules of Mt) exhibit multiple shapes with sizes between 20 and 200 nm. AuMt were tested on methylene blue degradation in homogeneous catalysis adding sodium borohydride. The smallest NPs (AuMt1) have a degradation coefficient of 0.008/s and reach 50% degradation in 190s. Cell viability and cytotoxicity were evaluated in human umbilical vein endothelial cells (HUVEC), and a moderate cytotoxic effect at 24 and 48 h was found. However, toxicity does not behave in a dose-dependent manner. Cellular internalization of AuMt on HUVEC cells was analyzed by confocal laser scanning microscopy. For AuMt1, it can be observed that the material is dispersed into the cytoplasm, while in AuMt2, the material is concentrated in the nuclear periphery.

Effect of synthesis, purification and growth determination methods on the antibacterial and antifungal activity of gold nanoparticles

In recent years, both nanotechnology and the use of nanomaterials have been growing in fields as diverse as biomedicine, food or electronics. Particularly metal nanoparticles, such as gold nanoparticles (AuNPs), are being widely studied with different applications, for example as an antimicrobial agent, in hyperthermic therapy or drug transport. Gold nanoparticles can be synthesized by different methods, such as stand out reduction with citrate or greener methods that use greener reducing agents (e.g. stainless steel). In the present work, both the effect of the synthesis method yielding AuNPs with similar size and purification of AuNPs affect the antibacterial and antifungal activities of the AuNPs obtained by citrate reduction and with stainless steel. The growth curves of the gram-negative (E. coli) and gram-positive bacteria (S. aureus) and the yeast C. albicans were constructed and the cell viability was evaluated by (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT). According to our results, the purification of the AuNPs after their synthesis and the growth determination method affect the antibacterial and antifungal activities while the synthesis method shows no significant differences.

The Influence of CTAB-Capped Seeds and Their Aging Time on the Morphologies of Silver Nanoparticles

Contrast to the polydisperse nanorods formed by common seed-mediated growth method without the presence of cetyltrimethylammonium bromide (CTAB) in seed solution, we successfully obtained silver nanoparticles with different morphologies in the same reaction system by addition of CTAB in the seed solution. In this work, an appropriate amount of CTAB was added into the solution to prepare silver seed crystals. The results show that the aging time of silver seeds have a great influence on the sizes and morphologies of silver nanoparticles and thus the shape-controllable silver nanoparticles can be easily achieved by simply changing the seed aging time. The results also support that the selective adsorption ability or adsorption behavior of TSC can be adjusted by adding CTAB in the preparation procedure of silver seeds. We suggest that different aging times generate different effects on the competitive adsorption between CTAB and citrate to induce the orientation growth of silver seeds. As a result, silver nanospheres, nanorods, and triangular nanoplates can be easily prepared in the same system. In addition, we overcome the time limitation about the use of the seeds by adding CTAB into seed solution and make the synthesis of silver or other metal nanoparticles with different morphologies more easily and more efficiently.

Synthesis of hyaluronic acid or O-carboxymethyl chitosan-stabilized ZnO–ginsenoside Rh2 nanocomposites incorporated with aqueous leaf extract of Dendropanax morbifera Léveille: in vitro studies as potential sunscreen agents

Synthesis of Rh2–ZnO nanocomposites stabilized with hyaluronic acid or O-carboxymethyl chitosan.

Antioxidant Potential of Artemisia capillaris, Portulaca oleracea, and Prunella vulgaris Extracts for Biofabrication of Gold Nanoparticles and Cytotoxicity Assessment

Three aqueous plant extracts (Artemisia capillaris, Portulaca oleracea, and Prunella vulgaris) were selected for the biofabrication of gold nanoparticles. The antioxidant activities (i.e., free radical scavenging activity, total phenolic content, and reducing power) of the extracts and how these activities affected the biofabrication of gold nanoparticles were investigated. P. vulgaris exerted the highest antioxidant activity, followed by A. capillaris and then P. oleracea. P. vulgaris was the most efficient reducing agent in the biofabrication process. Gold nanoparticles biofabricated by P. vulgaris (PV-AuNPs) had a maximum surface plasmon resonance of 530 nm with diverse shapes. High-resolution X-ray diffraction analysis showed that the PV-AuNPs had a face-centered cubic structure. The reaction yield was estimated to be 99.3% by inductively coupled plasma optical emission spectroscopy. The hydrodynamic size was determined to be 45 ± 2 nm with a zeta potential of - 13.99 mV. The PV-AuNPs exerted a dose-dependent antioxidant activity. Remarkably, the highest cytotoxicity of the PV-AuNPs was observed against human colorectal adenocarcinoma cells in the absence of fetal bovine serum, while for human pancreas ductal adenocarcinoma cells, the highest cytotoxicity was observed in the presence of fetal bovine serum. This result demonstrates that P. vulgaris extract was an efficient reducing agent for biofabrication of gold nanoparticles exerting cytotoxicity against cancer cells.