Green synthesis of silver nanoparticles usingPongamia pinnataseed: Characterization, antibacterial property, and spectroscopic investigation of interaction with human serum albumin

Pongamia pinnata seed extract-mediated green synthesis of silver nanoparticle loaded nanogel for estimation of their antipsoriatic properties

This research describes the eco-friendly green synthesis of silver nanoparticles employing Pongamia pinnata seed extracts loaded with nanogel formulations (AgNPs CUD NG) to improve the retention, accumulation, and the penetration of AgNPs into the epidermal layer of psoriasis. AgNPs were synthesized using the Box-Behnken design. Optimized AgNPs and AgNPs CUD NG were physico-chemically evaluated using UV-vis spectroscopy, SEM, FT-IR, PXRD, viscosity, spreadability, and retention studies. It was also functionally assessed using an imiquimod-induced rat model. The entrapment efficiency of AgNPs revealed ~ 79.35%. Physico-chemical parameters announced the formation of AgNPs via surface plasmon resonance and interaction between O-H, C = O, and amide I carbonyl group of protein extract and AgNO3. Optimized AgNPs showed spherical NPs ~ 116 nm with better physical stability and suitability for transdermal applications. AgNPs CUD NG revealed non-Newtonian, higher spreadability, and better extrudability, indicating its suitability for a transdermal route. AgNPs CUD NG enhanced the retention of AgNPs on the psoriatic skin compared to normal skin. Optimized formulations exhibit no irritation by the end of 72 h, indicating formulation safety. AgNPs CUD NG at a dose of 1 FTU showed significant recovery from psoriasis with a PASI score of ~ 0.8 compared to NG base and marketed formulations. Results indicated that seed extract-assisted AgNPs in association with CUD-based NG formulations could be a promising nanocarrier for psoriasis and other skin disorders.

An overview of green synthesized silver nanoparticles towards bioactive antibacterial, antimicrobial and antifungal applications

Present review emphatically introduces the synthesis, biocompatibility, and applications of silver nanoparticles (AgNPs), including their antibacterial, antimicrobial, and antifungal properties. A comprehensive discussion of various synthesis methods for AgNPs, with a particular focus on green chemistry mediated by plant extracts has been made. Recent research has revealed that the optical properties of AgNPs, including surface plasmon resonance (SPR), depend on the particle size, as well as the synthesis methods, preparation synthesis parameters, and used reducing agents. The significant emphasis on the use of synthesized AgNPs as antibacterial, antimicrobial, and antifungal agents in various applications has been reviewed. Furthermore, the application areas have been thoroughly examined, providing a detailed discussion of the underlying mechanisms, which aids in determining the optimal control parameters during the synthesis process of AgNPs. Furthermore, the challenges encountered while utilizing AgNPs and the corresponding advancements to overcome them have also been addressed. This review not only summarizes the achievements and current status of plant-mediated green synthesis of AgNPs but also explores the future prospects of these materials and technology in diverse areas, including bioactive applications.

Multi-spectroscopic and thermodynamic profiles on HSA binding of Cassia fistula leaf based potential antibacterial and anticancer silver nanoparticles

Here, a simple, one step, lucrative and green synthesis of Cassia fistula leaf extract inspired antibacterial silver nanoparticles (CF-SNPs) was provided. Characterization of these CF-SNPs were achieved by using various spectroscopic techniques for instance Ultraviolet Visible (UV-Vis) Spectroscopy, Fourier-Transform Infrared (FTIR) Spectroscopy, Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX). The effective antibacterial action of the CF-SNPs was checked against Escherichia coli (E. Coli) DH5-Alpha where MIC was 1.6 nM. Anticancer dynamism of the CF-SNPs was also tested in opposition to skin melanoma, A375 cell lines in which 4.4 nM was IC50. The binding proneness of HSA towards CF-SNPs was investigated by means of UV-Vis Spectroscopy, Fluorescence Spectroscopy, Time Resolved Fluorescence Spectroscopy, Circular Dichroism (CD) Spectroscopy, Dynamic Light Scattering, and Isothermal Titration Colorimetry (ITC). CD spectroscopy established minor secondary structural exchange of HSA in HSA-CF-SNPs complex. ITC and Time Resolved Fluorescence Spectroscopy verified the static type quenching mechanism involved in HSA-CF-SNPs complex. The binding constant was 3.45 × 108 M-1 at 298.15K from ITC study. The thermodynamic parameters showed that the interaction was occurred spontaneously by the hydrophilic forces and hydrogen bonding.Communicated by Ramaswamy H. Sarma.

Green synthesized Ag nanoparticles stimulate gene expression and paclitaxel production in Corylus avellana cells

Synthesis of nanoparticles (NPs) through plant extracts has been suggested as an effective and nature-friendly method. Paclitaxel is one of the most valuable secondary metabolites with therapeutic uses, and hazelnut has been suggested as one of the sustainable resources for producing this metabolite. In the present study, we synthesized Ag NPs using the ethanolic extract of C. avellana leaves and were characterized using UV-visible, FTIR, XRD, EDX, DLS, SEM, and TEM analyses. In addition, we investigated the effect of green synthesized Ag (GS Ag) NPs (5 and 10 mg/L), para-aminobenzoic acid (PABA) (20 mg/L), and AgNO3 (10 mg/L) on cell viability, physiological characteristics, gene expression, and biosynthesis of secondary metabolites in hazelnut cell cultures. The results showed that 10 mg/L Ag NPs and AgNO3 significantly affected the cell viability, the content of ROS, peroxidation of lipids, antioxidant capacity, secondary metabolite production, and expression pattern of the genes involved in the taxanes biosynthesis pathway in the hazelnut cells. The cytotoxicity increased by increasing the GS Ag NPs concentration from 5 to 10 mg/L, which was associated with reduced membrane integrity and cell viability. Elicitation of the cells with 10 mg/L Ag NPs combined with 20 mg/L PABA (as a precursor) remarkably excited the expression of TAT and GGPPS genes and the production of secondary metabolites as well as paclitaxel. So that the highest expression of TAT and GGPPS genes (3.71 and 3.69) and the highest amount of taxol (230.21 μg g-1 FW) and baccatin (1025.8 μg g-1 FW) were observed in this treatment. KEY POINTS: • For the first time, we assessed and reported the molecular and physiological responses of C. avellana cells to GS Ag NPs, AgNO3, and PABA. • In hazel cells, GS Ag NPs stimulate several physiological and molecular responses. • In addition to increasing antioxidant activity, GS Ag NPs significantly increased the expression of genes involved in the paclitaxel biosynthesis pathway and the production of secondary metabolites.

Insulin-cobalt core-shell nanoparticles for receptor-targeted bioimaging and diabetic wound healing

Diabetic wounds represent a major issue in medical care and need advanced therapeutic and tissue imaging systems for better management. The utilization of nano-formulations involving proteins like insulin and metal ions plays significant roles in controlling wound outcomes by decreasing inflammation or reducing microbial load. This work reports the easy one-pot synthesis of extremely stable, biocompatible, and highly fluorescent insulin-cobalt core-shell nanoparticles (ICoNPs) with enhanced quantum yield for their highly specific receptor-targeted bioimaging and normal and diabetic wound healing in vitro (HEKa cell line). The particles were characterized using physicochemical properties, biocompatibility, and wound healing applications. FTIR bands at 670.35 cm^-1, 849.79, and 973.73 indicating the Co-O bending, CoO-OH bond, and Co-OH bending, respectively, confirm the protein-metal interactions, which is further supported by the Raman spectra. In silico studies indicate the presence of cobalt binding sites on the insulin chain B at 8 GLY, 9 SER, and 10 HIS positions. The particles exhibit a magnificent loading efficiency of 89.48 ± 0.049% and excellent release properties (86.54 ± 2.15% within 24 h). Further, based on fluorescent properties, the recovery process can be monitored under an appropriate setup, and the binding of ICoNPs to insulin receptors was confirmed by bioimaging. This work helps synthesize effective therapeutics with numerous wound-healing promoting and monitoring applications.

CuONPs/MWCNTs/carbon paste modified electrode for determination of tramadol: theoretical and experimental investigation

A practical technique was applied to fabricate CuO nanostructures for use as the electrocatalyst. The green synthesis of cupric oxide nanoparticles (CuO NPs) via co-precipitation is described in this paper using an aqueous extract of Origanum majorana as both reductant and stabilizer, accompanied by characterization via XRD, SEM, and FTIR. The XRD pattern revealed no impurities, whereas SEM revealed low agglomerated spherical particles. CuO nanoparticles and multi wall carbon nanotubes (MWCNTs) have been used to create a modified carbon paste electrode. Voltammetric methods were used to analyze Tramadol using CuONPs/MWCNT as a working electrode. The produced nanocomposite showed high selectivity for Tramadol analysis with peak potentials of ~ 230 mV and ~ 700 mV and Excellent linear calibration curves for Tramadol ranging from 0.08 to 500.0 µM with a correlation coefficient of 0.9997 and detection limits of 0.025. Also, the CuO NPs/MWCNT/CPE sensor shows an an appreciable sensitivity of 0.0773 μA/μM to tramadol. For the first time the B3LYP/LanL2DZ, quantum method was used to compute DFT to determine nanocomposites' connected energy and bandgap energy. Eventually, CuO NPs/CNT was shown to be effective in detecting Tramadol in actual samples, with a recovery rate ranging from 96 to 104.3%.

Nanoparticles in Drug Delivery: From History to Therapeutic Applications

Current research into the role of engineered nanoparticles in drug delivery systems (DDSs) for medical purposes has developed numerous fascinating nanocarriers. This paper reviews the various conventionally used and current used carriage system to deliver drugs. Due to numerous drawbacks of conventional DDSs, nanocarriers have gained immense interest. Nanocarriers like polymeric nanoparticles, mesoporous nanoparticles, nanomaterials, carbon nanotubes, dendrimers, liposomes, metallic nanoparticles, nanomedicine, and engineered nanomaterials are used as carriage systems for targeted delivery at specific sites of affected areas in the body. Nanomedicine has rapidly grown to treat certain diseases like brain cancer, lung cancer, breast cancer, cardiovascular diseases, and many others. These nanomedicines can improve drug bioavailability and drug absorption time, reduce release time, eliminate drug aggregation, and enhance drug solubility in the blood. Nanomedicine has introduced a new era for drug carriage by refining the therapeutic directories of the energetic pharmaceutical elements engineered within nanoparticles. In this context, the vital information on engineered nanoparticles was reviewed and conferred towards the role in drug carriage systems to treat many ailments. All these nanocarriers were tested in vitro and in vivo. In the coming years, nanomedicines can improve human health more effectively by adding more advanced techniques into the drug delivery system.

Comparison of In Vitro Approaches to Assess the Antibacterial Effects of Nanomaterials

The antibacterial properties of nanomaterials (NMs) can be exploited in a range of consumer products (e.g., wound dressings, food packaging, textiles, medicines). There is also interest in the exploitation of NMs as treatments for infectious diseases to help combat antibiotic resistance. Whilst the antibacterial activity of NMs has been assessed in vitro and in vivo in numerous studies, the methodology used is very varied. Indeed, while numerous approaches are available to assess the antibacterial effect of NMs in vitro, they have not yet been systematically assessed for their suitability and sensitivity for testing NMs. It is therefore timely to consider what assays should be prioritised to screen the antibacterial properties of NMs. The majority of existing in vitro studies have focused on investigating the antibacterial effects exhibited by silver (Ag) NMs and have employed a limited range of assays. We therefore compared the antibacterial effects of copper oxide (CuO) NMs to Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis at various concentrations (12.5-200 µg/mL) using a battery of tests (well and disc diffusion, plate counts-time-kill method, optical density measurement-OD, Alamar Blue and live/dead viability assays, and quantitative polymerase chain reaction). CuO NMs were most toxic to B. subtilis and E. coli, while P. aeruginosa was the least sensitive strain. All assays employed detected the antibacterial activity of CuO NMs; however, they varied in their sensitivity, time, cost, technical difficulty and requirement for specialized equipment. In the future, we suggest that a combination of approaches is used to provide a robust assessment of the antibacterial activity of NMs. In particular, we recommend that the time-kill and OD assays are prioritised due to their greater sensitivity. We also suggest that standard operating protocols are developed so that the antibacterial activity of NMs can be assessed using a harmonised approach.

A review of the phytochemical mediated synthesis of AgNP (silver nanoparticle): the wonder particle of the past decade

Silver nanoparticle (AgNP) has been one of the most commonly used nanoparticles since the past decade for a wide range of applications, including environmental, agricultural, and medical fields, due to their unique physicochemical properties and ease of synthesis. Though chemical and physical methods of fabricating AgNPs have been quite popular, they posed various environmental problems. As a result, the bioinspired route of AgNP synthesis emerged as the preferred pathway for synthesis. This review focuses extensively on the biosynthesis of AgNP-mediated through different plant species worldwide in the past 10 years. The most popularly utilized application areas have been highlighted with their in-depth mechanistic approach in this review, along with the discussion on the different phytochemicals playing an important role in the bio-reduction of silver ions. In addition to this, the environmental factors which govern their synthesis and stability have been reviewed. The paper systematically analyses the trend of research on AgNP biosynthesis throughout the world through bibliometric analysis. Apart from this, the feasibility analysis of the plant-mediated synthesis of nanoparticles and their applications have been intrigued considering the perspectives of engineering, economic, and environmental limitations. Thus, the review is not only a comprehensive summary of the achievements and current status of plant-mediated biosynthesis but also provides insight into emerging future research frontier.

Biologically synthesized silver nanoparticles, mediated by Bothriochloa laguroides, inhibit biofilm formation and eradicate mature biofilm of Yersinia enterocolitica and Staphylococcus aureus

AIMS

To phytosynthesize silver nanoparticles (AgNPs) and determine their antibacterial and antibiofilm capacity against gram-positive and gram-negative bacterial strains.

METHODS AND RESULTS

AgNPs were synthesized using Bothriochloa laguroides aqueous extract as reducing and stabilizing agent. After characterization, a phytochemical screening to the extract and the AgNPs was performed. Antibacterial activity, inhibition and eradication of biofilms against Staphylococcus aureus and Yersinia enterocolitica strains were tested. Spherical AgNPs with an average size of 8 nm were obtained. Tannins, flavonoids, carbohydrates, proanthocyanidins, anthocyanins and saponins were identified in aqueous extract; meanwhile, only carbohydrates were identified in AgNPs. The MIC and MBC were determined at pmol L^-1  levels for all tested strains. Furthermore, AgNPs inhibited more than 90% of biofilms formation and eradicated more than 80% of mature biofilms at concentrations higher than MIC.

CONCLUSIONS

The AgNPs obtained in this study inhibited planktonic and sessile growth, and eradicated mature biofilms of pathogenic bacterial strains at very low concentrations.

SIGNIFICANCE AND IMPACT OF STUDY

The current study showed the promising potential of AgNPs as antibiofilm agents opening the way for the future development of a new class of antibacterial products.

Antimicrobial activity of biosynthesized silver nanoparticles, amoxicillin, and glass-ionomer cement againstStreptococcus mutansandStaphylococcus aureus

Background. The development of dental caries is associated with various microorganisms and secondary caries formation is the main cause of restorations failure. The advice for restorative dental materials that have antimicrobial properties has stimulated the introduction of materials containing different antibacterial agents.Objectives. The present study has been designed to synthesize silver nanoparticles (AgNPs) and incorporate AgNPs and amoxicillin into glass ionomer cement (GIC) to synergize its effect on oral microbes. The effect of the added antimicrobial agents on compressive strength (CS) of GIC was also evaluated.Material and methods. Biosynthesis of AgNPs was done usingCupressus macrocarpaextract and AgNPs were characterized. A total of 120 disc-shaped specimens were prepared and classified into 4 main groups where Group A includes conventional GIC, Groups B and C include GIC with AgNPs or amoxicillin, respectively, while Group D included GIC with both AgNPs and amoxicillin. Each group was tested for the antimicrobial activity against bothStreptococcus mutans(S. mutans) andStaphylococcus aureus(S. aureus). The distribution of biofilm was examined via a scanning electron microscope. The CS of the tested material was measured using a Material Test System.Results. The UV-visible spectrum showed a peak of 429 nm. Transmission electron microscopy, x-ray diffraction pattern and Fourier transform infrared analysis confirmed the formation of AgNPs with spherical to oblong polydispersed particles of diameter in the range of 13.5-25.8 nm. The maximum inhibitory zone was recorded for group D against both tested bacteria with a mean of 29 mm at first 24 h period to 15 mm at three weeks and showed antimicrobial rate 92.2% and 92.56%, against both strains, respectively. Additionally, group D disintegrated the structure ofS. aureusbiofilm and even kill bacteria in the biofilms. The addition of AgNPs and amoxicillin caused an insignificant effect on CS of GIC.Conclusion.TheAgNPs showed a synergistic effect in combination with amoxicillin and GIC dental restorative material against studied microorganisms. The agents can be safely added with minimal effect on the mechanical properties of the original cement.

Biogenic Fabrication, Characterization and Drug Loaded Antimicrobial Assay of Silver Nanoparticles Using Centratherum anthalminticum (L.) Kuntze

Bionanotechnology is considered a safe and ecofriendly route for the biosynthesis of metal nanoparticles from plant extracts, microorganisms, and biomaterials. The present study was focused on the fabrication of silver nanoparticles (<50 nm) biogenically from the novel Centratherum anthelmminticum's aqueous seed extract. The obtained nanoproduct was evaluated by X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM), UV-Visible spectroscopy, FTIR and Raman spectroscopy. The particle size and surface charge were estimated by Dynamic light scattering (DLS) and Zeta potential measurements. The nanoparticles showed cubic close packed (ccp) morphology with miller indices (111), (200), (220), (311) and (222). The λ_max for synthesized silver nanoparticles was measured in the range of 436 nm, 464 nm and 467 nm for 1 mM, 5 mM and 10 mM samples, respectively. The bioreduction of silver ions exhibited a gradual color change which confirms the formation of silver nanoparticles under UV-visible spectrum. Ag-O and Ag-N stretching vibrations corresponding to the bond formation between silver and oxygen of the carboxylate group and nitrogen of amine was corroborated by the presence of a sharp peak in Raman spectra at 245 cm^-1. Antimicrobial activity was assessed against eight bacterial and three fungal strains. The silver nanoparticles fabricated from 10 mM AgNO₃ solution showed significant results against all Gram-negative bacteria, with the further restriction in growth of C. albicans and A. niger. From in-vitro antimicrobial assay, it was observed that drug-loaded silver nanoparticles (Ciprofloxacin +10 mM) displayed a stronger potential than the synthesized silver nanoparticles and ciprofloxacin alone to restrain the development of E. coli, and E. aerogenes.

Biocontrol of mosquito vectors through herbal-derived silver nanoparticles: prospects and challenges

Mosquitoes spread several life-threatening diseases such as malaria, filaria, dengue, Japanese encephalitis, West Nile fever, chikungunya, and yellow fever and are associated with millions of deaths every year across the world. However, insecticides of synthetic origin are conventionally used for controlling various vector-borne diseases but they have various associated drawbacks like impact on non-targeted species, negative effects on the environment, and development of resistance in vector species by alteration of the target site. Plant extracts, phytochemicals, and their nanoformulations can serve as ovipositional attractants, insect growth regulators, larvicides, and repellents with least effects on the environment. Such plant-derived products exhibit broad-spectrum resistance against various mosquito species and are relatively cheaper, environmentally safer, biodegradable, easily accessible, and are non-toxic to non-targeted organisms. Therefore, in this review article, the current knowledge of phytochemical sources exhibiting larvicidal activity and their variations in response to solvents used for their extraction is underlined. Also, different methods such as physical, chemical, and biological for silver nanoparticle (AgNPs) synthesis, their mechanism of synthesis using plant extract, their potent larvicidal activity, and the possible mechanism by which these particles kill mosquito larvae are discussed. In addition, constraints related to commercialization of nanoherbal products at government and academic or research level and barriers from laboratory experiments to field trial have also been discussed. This comprehensive information can be gainfully employed for the development of herbal larvicidal formulations and nanopesticides against insecticide-resistant vector species in the near future. Graphical abstract.

Biophysical insights into the interaction of human serum albumin with Cassia fistula leaf extracts inspired biogenic potent antibacterial and anticancerous gold nanoparticles

In the present investigation, the characterization of Cassia fistula leaf extracts (CFLE) mediated gold nanoparticles (CF-GNPs) and its binding features with human serum albumin (HSA) through interaction have been probed. The results from UV-visible, TEM and EDX analysis proved the formation of CF-GNPs. The functional groups like OH, NH, CN etc present in the phytochemicals of CFLE were mainly acted as reducing and protecting agent which was confirmed by FTIR study. The zeta potential (-17.8 mV) and hydrodynamic size (20.4 nm) of the CF-GNPs were also measured by DLS. The microbicidal effect of the CF-GNPs was estimated against gram negative bacterium, Escherichia coli (DH5-Alpha) and MIC was found to be 2.8 nM. Anticancer activity of the CF-GNPs was also checked against A375 (skin melanoma) cell lines where IC₅₀ was 6.5 nM. The interaction study of CF-GNPs with HSA and conformational alteration of HSA upon interaction were investigated by the fluorescence, lifetime, synchronous, circular dichroism spectrum and zeta potential measurement. The negative value of Gibb's free energy indicated spontaneity of the CF-GNPs-HSA complex formation. The fluorescence lifetime measurement confirmed the construction of ground state CF-GNPs-HSA complex passing through static quenching mechanism and determined the distance from donor to acceptor also. Circular dichroism spectroscopy signified unchangeable native structure of HSA with minor decrease of alpha helix structure (54.5% to 51.1%) upon interaction. The more negative zeta potential value (-25.9 mV) of CF-GNPs-HSA system than the CF-GNPs (-17.8 mV) proved the adsorption of HSA on the outer surface of CF-GNPs.Communicated by Ramaswamy H. Sarma.

Simple and cleaner system of silver nanoparticle synthesis using kenaf seed and revealing its anticancer and antimicrobial potential

The clean and eco-friendly synthesis of silver nanoparticles (AgNPs) has provided promising characteristics with impressive biomedical related potential. Here, we have employed a green process for the synthesis of AgNPs using kenaf seed (KS) extract as a bilateral mediator for reducing and capping of Ag⁺ ions under hydrothermal condition. The synthesis pathways, such as varying amounts of KS, Ag ion concentration and autoclaving time were optimized. The manifestation of a strong absorption peak from 420-430 nm in UV-vis spectroscopy indicated the successful synthesis of KS@AgNPs. Fourier transform infrared spectroscopy confirmed the presence of hydroxyl and carbonyl functionalities involved in the reduction and stabilization of Ag⁺ ions. Furthermore, transmission electron microscopy revealed that the KS@AgNPs are spherical in shape having a size around 7-11 nm, whereas high-quality crystals were evidenced by x-ray diffraction analysis. Moreover, inductively coupled plasma-optical emission spectrometry revealed that 19.6 μg l^-1 of Ag⁺ ions were released from the KS@AgNPs. In cell line studies, KS@AgNPs at a higher dose were shown to be non-toxic to the healthy (NIH3T3) cells, while strong anti-proliferative response was found in the case of lung cancer (A549) cells. Furthermore, a significant zone of inhibition was observed for both Gram-positive and Gram-negative microorganisms, and a combination of KS@AgNPs with ampicillin revealed a notable synergistic anti-pathogenic effect. Overall, our study proved the potentiality of KS as an efficient bio-resource for the synthesis of AgNPs and also its original feature as an anti-cancer and antimicrobial agent.

Effect of feed supplementation with biosynthesized silver nanoparticles using leaf extract of Morus indica L. V1 on Bombyx mori L. (Lepidoptera: Bombycidae)

Herein, we report the synthesis of silver nanoparticles (AgNPs) by a green route using the aqueous leaf extract of Morus indica L. V1. The synthesized AgNPs exhibited maximum UV-Vis absorbance at 460 nm due to surface plasmon resonance. The average diameter (~54 nm) of AgNPs was measured from HR-TEM analysis. EDX spectra also supported the formation of AgNPs, and negative zeta potential value (-14 mV) suggested its stability. Moreover, a shift in the carbonyl stretching (from 1639 cm-1 to 1630 cm-1) was noted in the FT-IR spectra of leaf extract after AgNPs synthesis which confirm the role of natural products present in leaves for the conversion of silver ions to AgNPs. The four bright circular rings (111), (200), (220) and (311) observed in the selected area electron diffraction pattern are the characteristic reflections of face centered cubic crystalline silver. LC-MS/MS study revealed the presence of phytochemicals in the leaf extract which is responsible for the reduction of silver ions. MTT assay was performed to investigate the cytotoxicity of AgNPs against two human cell lines, namely HepG2 and WRL-68. The antibacterial study revealed that MIC value of the synthesized AgNPs was 80 µg/ml against Escherichia coli K12 and Staphylococcus aureus (MTCC 96). Finally, the synthesized AgNPs at 10 µg/ml dosages showed beneficial effects on the survivability, body weights of the Bombyx mori L. larvae, pupae, cocoons and shells weights via enhancing the feed efficacy.

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

BACKGROUND

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

METHODS

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

RESULT

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

CONCLUSION

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

Green synthesis of silver nanoparticles: biomolecule-nanoparticle organizations targeting antimicrobial activity

Since discovery of the first antibiotic drug, penicillin, in 1928, a variety of antibiotic and antimicrobial agents have been developed and used for both human therapy and industrial applications. However, excess and uncontrolled use of antibiotic agents has caused a significant growth in the number of drug resistant pathogens. Novel therapeutic approaches replacing the inefficient antibiotics are in high demand to overcome increasing microbial multidrug resistance. In the recent years, ongoing research has focused on development of nano-scale objects as efficient antimicrobial therapies. Among the various nanoparticles, silver nanoparticles have gained much attention due to their unique antimicrobial properties. However, concerns about the synthesis of these materials such as use of precursor chemicals and toxic solvents, and generation of toxic byproducts have led to a new alternative approach, green synthesis. This eco-friendly technique incorporates use of biological agents, plants or microbial agents as reducing and capping agents. Silver nanoparticles synthesized by green chemistry offer a novel and potential alternative to chemically synthesized nanoparticles. In this review, we discuss the recent advances in green synthesis of silver nanoparticles, their application as antimicrobial agents and mechanism of antimicrobial mode of action.

Biogenic synthesis of AgNPs using Artemisia oliveriana extract and their biological activities for an effective treatment of lung cancer

Silver nanoparticles (AgNPs) were synthesized using Artemisia oliveriana extract, and their physicochemical characteristics were studied. The antioxidant and antimicrobial activities of the AgNPs, as well as their anticancer effects on the lung cancer cell line (A549), using 1,1-diphenyl-2-picrylhydrazyl (DPPH), MIC and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) techniques respectively demonstrated that the synthesized AgNPs mainly affected the gram-positive bacteria rather than the gram-negative bacteria, and exhibited significant cellular toxicity on the A549 cell line. Further, the cellular uptake of the AgNPs results indicated that the AgNPs accumulated within the cell. Moreover, their impact on the expression of apoptotic genes including Bax, Bcl-2, caspase-3 (CASP3), caspase-9 (CASP9) and miR-192 using real-time PCR demonstrated substantial increase in the expression of all mentioned genes (p<.001). Finally, the apoptotic effects of the AgNPs through DNA fragmentation test, flow cytometry and cell cycle analysis indicated the induction of apoptosis in the A549 cell line. The results revealed that the AgNPs synthesized using A. oliveriana extract have potential biological applications.

Novel nano-insulin formulation modulates cytokine secretion and remodeling to accelerate diabetic wound healing

Little is known about insulin's wound healing capability in normal as well as diabetic conditions. We here report specific interaction of silver nanoparticles (AgNPs) with insulin by making a ~2 nm thick coat around the AgNPs and its potent wound healing efficacy. Characterization of the interaction of human insulin with silver nanoparticles showed confirmed alteration of amide-I in insulin whereas amide-II and III remained unaltered. Further, nanoparticles protein interaction kinetics showed spontaneous interaction at physiological temperature with ΔG, ΔS, Ea and Ka values -7.48, 0.076, 3.84 kcal mol^-1 and 6 × 10⁵ s^-1 respectively. Insulin loaded AgNPs (IAgNPs) showed significant improvement in healing activity in vitro (HEKa cells) and in vivo (Wister Rats) in comparison with the control in both normal and diabetic conditions. The underlying mechanism was attributed to a regulation of the balance between pro (IL-6, TNFα) and anti-inflammatory cytokines (IL-10) at the wound site to promote faster wound remodeling.

Biomimetic synthesis of silver nanoparticles using Matricaria chamomilla extract and their potential anticancer activity against human lung cancer cells

Herbs having various natural substances can be utilized for the biosynthesis of Silver nanoparticles (AgNPs) and act as a stable, reliable and biocompatible alternative instead of the current physical and chemical approaches. It has been reported that Matricaria chamomilla possesses unique properties, especially anti-cancerous effects. The objective of the current work was to assess the chemical characteristics and anticancer effects of biosynthesized AgNPs applying aqueous extracts of M. chamomilla against A549 lung cancer cells. UV-visible spectrum showed the maximum absorption of the biosynthesized AgNPs at 430 nm. The crystalline structure of biosynthesized AgNPs in optimal conditions was confirmed by XRD. Moreover, the presence of Ag as the ingredient element was exhibited via EDX analysis. FT-IR results also verified the AgNPs synthesis using a plant extract. The spherical shapes of the AgNPs with an average diameter size around 45.12 nm and a zeta potential value of -34 mV were characterized using DLS, and confirmed through FE-SEM and TEM. In vitro cytotoxicity assay using MTT revealed that the biosynthesized AgNPs exhibited a dose- and time- dependent cytotoxic effect against A549 lung cancer cells. Moreover, the apoptotic effects of the AgNPs were demonstrated using DAPI staining, real-time PCR and flow cytometry. According to these findings, using M. chamomilla in combination with AgNPs via green-synthesis approach may be an efficient strategy for effective treatment of lung cancer.

Bactericidal Properties of Plants-Derived Metal and Metal Oxide Nanoparticles (NPs)

Nanoparticles (NPs) are nano-sized particles (generally 1–100 nm) that can be synthesized through various methods. The wide range of physicochemical characteristics of NPs permit them to have diverse biological functions. These particles are versatile and can be adopted into various applications, particularly in biomedical field. In the past five years, NPs’ roles in biomedical applications have drawn considerable attentions, and novel NPs with improved functions and reduced toxicity are continuously increasing. Extensive studies have been carried out in evaluating antibacterial potentials of NPs. The promising antibacterial effects exhibited by NPs highlight the potential of developing them into future generation of antimicrobial agents. There are various methods to synthesize NPs, and each of the method has significant implication on the biological action of NPs. Among all synthetic methods, green technology is the least toxic biological route, which is particularly suitable for biomedical applications. This mini-review provides current update on the antibacterial effects of NPs synthesized by green technology using plants. Underlying challenges in developing NPs into future antibacterials in clinics are also discussed at the present review.

A review on biosynthesis of silver nanoparticles and their biocidal properties

Use of silver and silver salts is as old as human civilization but the fabrication of silver nanoparticles (Ag NPs) has only recently been recognized. They have been specifically used in agriculture and medicine as antibacterial, antifungal and antioxidants. It has been demonstrated that Ag NPs arrest the growth and multiplication of many bacteria such as Bacillus cereus, Staphylococcus aureus, Citrobacter koseri, Salmonella typhii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, Vibrio parahaemolyticus and fungus Candida albicans by binding Ag/Ag+ with the biomolecules present in the microbial cells. It has been suggested that Ag NPs produce reactive oxygen species and free radicals which cause apoptosis leading to cell death preventing their replication. Since Ag NPs are smaller than the microorganisms, they diffuse into cell and rupture the cell wall which has been shown from SEM and TEM images of the suspension containing nanoparticles and pathogens. It has also been shown that smaller nanoparticles are more toxic than the bigger ones. Ag NPs are also used in packaging to prevent damage of food products by pathogens. The toxicity of Ag NPs is dependent on the size, concentration, pH of the medium and exposure time to pathogens.

Green synthesis of silver nanoparticles using Anthemis atropatana extract: characterization and in vitro biological activities

This study aim to synthesize silver nanoparticles (AgNPs) using Anthemis atropatana extract and to evaluate their chemical characteristics and antimicrobial and cytotoxic effects. The biosynthesis of AgNPs is verified using UV-visible spectrum which showing maximum absorption in 430 nm wavelength. Transmission electron microscope (TEM) and scanning electron microscope (SEM) results revealed that AgNPs has a spherical shape with an average size of 38.89 nanometres. The crystalline structure of green synthesized AgNPs in optimal conditions was confirmed by XRD analysis. The pattern of XRD peaks related to face-centred cubic (fcc) (111), (200), (220), (311) and (222) observed. Also, FTIR results verified the AgNPs synthesis using plant extract. In biological tests, the MTT results indicate the dose dependence of cytotoxic effects of AgNPs on colon cancer cell lines (HT29). The AgNPs had maximum cytotoxicity on HT29 cancer cell line at 100 μg/ml concentration, which were statistically significant comparing control cells (p < .001). Moreover, real time PCR and flow cytometry results confirmed the apoptotic effects of AgNPs. According to the results, it seems that the green synthesis of AgNPs is an eco-friendly and cost effective approach. This research provides insight into the development of new anticancer and antibacterial agents.