Green synthesis of nanoparticles and its potential application

Nanotechnology is a new and emerging technology with wealth of applications. It involves the synthesis and application of materials having one of the dimensions in the range of 1–100 nm. A wide variety of physico–chemical approaches are being used these days for the synthesis of nanoparticles (NPs). However, biogenic reduction of metal precursors to produce corresponding NPs is eco-friendly, less expensive, free of chemical contaminants for medical and biological applications where purity of NPs is of major concern. Biogenic reduction is a “Bottom Up” approach similar to chemical reduction where a reducing agent is replaced by extract of a natural products with inherent stabilizing, growth terminating and capping properties. Furthermore, the nature of biological entities in different concentrations in combination with reducing organic agents influence the size and shape of NPs. Present review focuses on microbes or plants based green synthesis of Ag, Au, Cu, Fe, Pd, Ru, PbS, CdS, CuO, CeO₂, Fe₃O₄, TiO₂, and ZnO NPs and their potential applications.     

Green synthesis of selenium nanoparticles using Rosmarinus officinalis and investigated their antimicrobial activity

BioMetals - The interest of many has been attracted by plant-mediated synthesizing procedures for nanoparticles since they provide certain qualities including being cost-effective, quick, and...     

Proliferative activity of Echinacea angustifolia root extracts on cancer cells: Interference with doxorubicin cytotoxicity

Doxorubicin is an anticancer drug that causes apoptosis in cells, but cardiotoxicity limits the cumulative dose that can remain in the blood. Echinacea extracts have been prescribed to supplement cancer chemotherapy. In a recent study, it was reported that Echinacea purpurea extracts protected noncancerous cells from apoptosis. Our study aimed to determine interference with doxorubicin chemotherapy, and if fractions and compounds from Echinacea angustifolia roots protected the cells. Cervical and breast cancer cells were treated with the Echinacea samples and doxorubicin. At 0.05 and 0.5 microM doxorubicin concentration, cynarine increased HeLa cell growth by 48-125% and 29-101%, respectively (p<0.01). At 0.05 microM doxorubicin concentration, chicoric acid increased cell growth by 23-100% (p<0.01). When MCF-7 cells were treated with Echinacea and doxorubicin, the ethyl acetate fraction increased cell growth by 20-25%, and chicoric acid increased cell growth by 10-15%. Cynarine showed proliferative activity on HeLa cells, but showed antiproliferative activity on MCF-7 cells. Results indicate that phenolic compounds are responsible for proliferative activity. Studies with individual compounds show that chicoric acid and cynarine interfered with cells treated with 0.5 microM doxorubicin. The results of this study show that Echinacea herbal medicines affect cell proliferation despite cancer treatment, and that herbal medicines require further study with respect to anticancer drugs.     

Pathway of cytotoxicity induced by folic acid modified selenium nanoparticles in MCF-7 cells

Selenium nanoparticles (Se NPs) have been recognized as promising materials for biomedical applications. To prepare Se NPs which contained cancer targeting methods and to clarify the cellular localization and cytotoxicity mechanisms of these Se NPs against cancer cells, folic acid protected/modified selenium nanoparticles (FA–Se NPs) were first prepared by a one-step method. Some morphologic and spectroscopic methods were obtained to prove the successfully formation of FA–Se NPs while free folate competitive inhibition assay, microscope, and several biological methods were used to determine the in vitro uptake, subcellular localization, and cytotoxicity mechanism of FA–Se NPs in MCF-7 cells. The results indicated that the 70-nm FA–Se NPs were internalized by MCF-7 cells through folate receptor-mediated endocytosis and targeted to mitochondria located regions through endocytic vesicles transporting. Then, the FA–Se NPs entered into mitochondria; triggered the mitochondria-dependent apoptosis of MCF-7 cells which involved oxidative stress, Ca²+ stress changes, and mitochondrial dysfunction; and finally caused the damage of mitochondria. FA–Se NPs released from broken mitochondria were transported into nucleus and further into nucleolus which then induced MCF-7 cell cycle arrest. In addition, FA–Se NPs could induce cytoskeleton disorganization and induce MCF-7 cell membrane morphology alterations. These results collectively suggested that FA–Se NPs could be served as potential therapeutic agents and organelle-targeted drug carriers in cancer therapy.     

Green synthesis,characterization and biological activity of Solanum trilobatum-mediated silver nanoparticles

Biologically inspired synthesis of nanoparticles was found to be more attractive in metal nanoparticle synthesis. The present study reported an in-situ biogenic synthesis of silver nanoparticles (AgNPs) using Solanum trilobatum aqueous leaf extract. On this basis, the aqueous leaf extract of S. trilobatum acted as a reducing agent and stabilizing agent to synthesize highly stable AgNPs at ambient temperature. Eventually, the synthesized and stabilized AgNPs surface plasmon resonance was near 430 nm through a UV–visible (UV–vis) spectrophotometer. Here, the stability of the silver colloids monitored through zeta potential and mean particle size was evaluated through diffraction light scattering (DLF). Further, the average particle size was found to be 27.6 nm and spherical, confirmed with transmission electron microscopy (TEM). Also, colloidal AgNPs and aqueous extract are found to be rich sources of antioxidants and exhibit higher free radical scavenging ability. Thus, efficient inhibition with COX1 and COX2 enzymes and the protective effect with human red blood cell (HRBC) membrane stability showed significant results. These features are promising, suggesting the possibility of the AgNPs to be useful to disease-modifying for treating inflammatory disorders and associated complications.     

Green synthesis and characterization of gold nanoparticles using endophytic fungi Fusarium solani and its in-vitro anticancer and biomedical applications

The present study aimed to explore the anticancer potentials of the gold nanoparticles (NPs) obtained by green synthesis method using an endophytic strain Fusarium solani ATLOY – 8 has been isolated from the plant Chonemorpha fragrans. The formation of the NPs was analyzed by UV, FTIR, SEM and XRD. The synthesized NPs showed pink-ruby red colors and high peak plasmon band was observed between 510 and 560 nm. It is observed that intensity of absorption steadily increases the wavelength and band stabilizes at 551 nm. The XRD pattern revealed the angles at 19, 38.32, 46.16, 57.50, and 76.81° respectively. Interestingly, the FTIR band absorption noted at 1413 cm⁻¹, 1041 cm⁻¹ and 690 cm⁻¹ ascribed the presence of amine II bands of protein, C-N and C-H stretching vibrations of the nanoparticles. SEM analysis indicated that the average diameter of the synthesized nanoparticles was between 40 and 45 nm. These NPs showed cytotoxicity on cervical cancer cells (He La) and against human breast cancer cells (MCF-7) and the NPs exhibited dose dependent cytotoxic effect. IC50 value was 0.8 ± 0.5 μg/mL on MCF-7 cell line and was found to be 1.3 ± 0.5 μg/mL on MCF-7 cell lines. The synthesized NPs induced apoptosis on these cancer cell lines. The accumulation of apoptotic cells decreased in sub G0 and G1 phase of cell cycle in the MCF-7 cancer cells were found to be 55.13%, 52.11% and 51.10% after 12 h exposure to different concentrations. The results altogether provide an apparent and versatile biomedical application for safer chemotherapeutic agent with little systemic toxicity.     

Green synthesis and characterization of zinc oxide nanoparticles using Cayratia pedata leaf extract

The synthesis of Zinc oxide nanoparticles using a plant-mediated approach is presented in this paper. The nanoparticles were successfully synthesized using the Nitrate derivative of Zinc and plant extract of the indigenous medicinal plant Cayratia pedata. 0.1 mM of Zn (NO₃)₂.6H₂O was made to react with the plant extract at different concentrations, and the reaction temperature was maintained at 55 °C, 65 °C, and 75 °C. The yellow coloured paste obtained was wholly dried, collected, and packed for further analysis. In the UV visible spectrometer (UV–Vis) absorption peak was observed at 320 nm, which is specific for Zinc oxide nanoparticles. The characterization carried out using Field Emission Scanning Electron Microscope (FESEM) reveals the presence of Zinc oxide nanoparticles in its agglomerated form. From the X-ray diffraction (XRD) pattern, the average size of the nanoparticles was estimated to be 52.24 nm. Energy Dispersive Spectrum (EDX) results show the composition of Zinc and Oxygen, giving strong energy signals of 78.32% and 12.78% for Zinc and Oxygen, respectively. Fourier Transform - Infra-Red (FT-IR) spectroscopic analysis shows absorption peak of Zn–O bonding between 400 and 600 cm^?1. The various characterization methods carried out confirm the formation of nano Zinc oxide. The synthesized nanoparticles were used in the immobilization of the enzyme Glucose oxidase. Relative activity of 60% was obtained when Glucose oxidase was immobilized with the green synthesized ZnO nanoparticles. A comparative study of the green synthesized with native ZnO was also carried out. This green method of synthesis was found to be cost-effective and eco-friendly.     

Green synthesis and physiochemical characterization of nickel oxide nanoparticles: Interaction studies with Calf thymus DNA

One of the most promising applications of nanomaterials is that of nanobiosensors, using biomolecules such as nucleic acids as receptors. This study aimed to synthesize nickel oxide nanoparticles (NiO NPs) by an environmentally friendly green synthesis, using the extract of the herb Coriandrum sativum (coriander). The synthesized NPs were characterized using UV–Visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, X‐ray photon spectroscopy, field emission scanning electron microscopy coupled with energy dispersive spectroscopy, dynamic light scattering, zeta potential and transmission electron microscopy. All results confirmed the synthesis of pure, spherical, positively charged NiO NPs of around 95 nm in diameter with prominent hydroxyl groups attached to the surface. Furthermore, interaction studies of synthesized NiO NPs with calf thymus DNA (CT DNA) were performed using UV–Visible spectroscopy, UV–thermal melting, circular dichroism, and fluorescence spectroscopy. CT DNA served as a substitute for nucleic acid biosensors. All experimental studies indicated that the NiO NPs bound electrostatically with CT DNA. These studies may facilitate exploring the potential of NiO NP–nucleic acid conjugated materials to be used as nanobiosensors for various applications, especially in pharmacological, epidemiological, and environmental diagnostic applications, and in detection.     

Biogenic selenium nanoparticles: characterization,antimicrobial activity and effects on human dendritic cells and fibroblasts

Tailored nanoparticles offer a novel approach to fight antibiotic‐resistant microorganisms. We analysed biogenic selenium nanoparticles (SeNPs) of bacterial origin to determine their antimicrobial activity against selected pathogens in their planktonic and biofilm states. SeNPs synthesized by Gram‐negative Stenotrophomonas maltophilia [Sm‐SeNPs(?)] and Gram‐positive Bacillus mycoides [Bm‐SeNPs(+)] were active at low minimum inhibitory concentrations against a number of clinical isolates of Pseudomonas aeruginosa but did not inhibit clinical isolates of the yeast species Candida albicans and C. parapsilosis. However, the SeNPs were able to inhibit biofilm formation and also to disaggregate the mature glycocalyx in both P. aeruginosa and Candida spp. The Sm‐SeNPs(?) and Bm‐SeNPs(+) both achieved much stronger antimicrobial effects than synthetic selenium nanoparticles (Ch‐SeNPs). Dendritic cells and fibroblasts exposed to Sm‐SeNPs(?), Bm‐SeNPs(+) and Ch‐SeNPs did not show any loss of cell viability, any increase in the release of reactive oxygen species or any significant increase in the secretion of pro‐inflammatory and immunostimulatory cytokines. Biogenic SeNPs therefore appear to be reliable candidates for safe medical applications, alone or in association with traditional antibiotics, to inhibit the growth of clinical isolates of P. aeruginosa or to facilitate the penetration of P. aeruginosa and Candida spp. biofilms by antimicrobial agents.     

Manipulation of cell cycle kinetics: Influence on the cytotoxicity of doxorubicin in human breast cancer cells

In vitro exposure of estrogen receptor-negative (ER-) EVSA-T human breast cancer cells to insulin and/or estradiol had no effect on cell cycle distribution, in contrast to a 3–5-fold increase in the percentages of cells in the S-phase of the cell cycle in the ER+ MCF-7 cell line. Estrogen pretreatment of MCF-7 cells followed by incubation with doxorubicin resulted in an augmented inhibition of cell growth compared to unstimulated controls. This delay in growth was accompanied by a decrease in the percentages of cells actively synthesizing DNA, and by an augmented percentage of cells exhibiting a G₂M-amount of DNA at the end of a 6–9 day period of culture in complete growth medium.     

佛波醇制备工艺优化及其衍生物的合成表征与细胞毒活性研究

目前佛波醇制备过程比较繁琐,本研究首先对制备工艺进行优化,使制备周期缩短至3天。然后以佛波醇、二十碳五烯酸、二十二碳六烯酸、花生酸为原料,设计合成了18个新化合物,运用1H NMR,13C NMR,HR-MS对化合物进行结构表征,并测试了这些化合物对人正常胚肺成纤维细胞(MRC-5)的毒性。结果显示13个化合物对正常细胞毒性较大(IC50<38.12μmol/L),5个化合物毒性较小(IC50> 100μmol/L)。佛波醇的12位羟基、13位羟基分别与长链饱和脂肪酸形成单酯时毒性较低,实验结果为佛波醇的结构修饰提供参考。     

Green synthesis,characterization, enhanced functionality and biological evaluation of silver nanoparticles based on Coriander sativum

The present study focused on the green synthesis of silver nanoparticles from Coriander sativum (CS) containing structural polymers, phenolic compounds and glycosidic bioactive macromolecules. Plant phenolic compounds can act as antioxidants, lignin, and attractants like flavonoids and carotenoids. Henceforth, silver nanoparticles (AgNPs) were prepared extracellularly by the combinatorial action of stabilizing and reduction of the CS leaf extract. The biologically synthesized CS-AgNPs were studied by UV-spectroscopy, zeta potential determination, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis to characterize and confirm the formation of crystalline nanoparticles. The synthesized nanoparticles demonstrated strong antimicrobial activity against all microbial strains examined with varying degrees. The scavenging action on free radicals by CS-AgNPs showed strong antioxidant efficiency with superoxide and hydroxyl radicals at different concentrations as compared with standard ascorbic acid. The presence of in vitro anticancer effect was confirmed at different concentrations on the MCF-7 cell line as revealed with decrease in cell viability which was proportionately related to the concentration of CS-AgNPs illustrating the toxigenic nature of synthesized nanoparticles on cancerous cells.     

One-pot synthesis of cinnamylideneacetophenones and their in vitro cytotoxicity in breast cancer cells

A series of cinnamylideneacetophenones were synthesized via a modified Claisen–Schmidt condensation reaction and evaluated for cytotoxicity against breast cancer cells using the Alamar Blue™ assay. Derivatives 17 and 18 bearing a 2-nitro group on the B ring, exhibited sub-micromolar cytotoxicity in MCF-7 cells (IC₅₀ = 71 and 1.9 nM), respectively. Derivative 17 also displayed sub-micromolar (IC₅₀ = 780 nM) cytotoxicity in MDA-MB-468 cells. Additionally, 17 and 18 displayed significantly less cytotoxicity than the chemotherapeutic doxorubicin in non-tumorigenic MCF-10A cells. This study provides evidence supporting the continued development of nitro-substituted cinnamylideneacetophenones as small molecules to treat breast cancer.     

Green synthesis of silver nanoparticles using Rhodobacter Sphaeroides

The use of microorganisms in the synthesis of nanoparticles emerges as an eco-friendly and exciting approach. In this study, silver nanoparticles were successfully synthesized from AgNO₃ by reduction of aqueous Ag⁺ ions with the cell filtrate of Rhodobacter sphaeroides. Nanoparticles were characterized by means of UV–vis absorption spectroscopy, X-Ray Diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Crystalline nature of the nanoparticles in the fcc structure are confirmed by the peaks in the XRD pattern corresponding to (111), (200), (220) and (311) planes, bright circular spots in the selected are a electron diffraction (SAED) and clear lattice fringes in the high-resolution TEM image. Also, the size of silver nanoparticles was controlled by the specific activity of nitrate reductase in the cell filtrate.     

Chloro and bromo-pyrazole curcumin Knoevenagel condensates augmented anticancer activity against human cervical cancer cells: design,synthesis, in silico docking and in vitro cytotoxicity analysis

Abstract

With an endeavor to develop novel curcumin analogs as potential anti-cancer agents, we designed and synthesized a series of Knoevenagel condensates by clubbing pyrazole carbaldehydes at the active methylene carbon atom of the curcumin backbone. Molecular docking studies were carried out to target the proposed derivatives on human kinase β (IKKβ), a potential anti-cancer target. The chloro derivative displayed five hydrogen bond interactions with a docking score of ?11.874?kcal/mol higher than curcumin (docking score =??7.434?kcal/mol). This was supported by the fact that the propellant shaped derivatives fitted aptly into the binding pocket. Molecular simulations studies were also conducted on the lead molecule and the results figured out that the stable complexes were developed as the minimal deviations per residue of protein within the range of 0.11–0.92 Å. The screened compounds were synthesized, characterized and evaluated in vitro for cytotoxicity against cervical cancer cell line, HeLa using standard cell proliferation assay. Chloro derivative and bromo analog demonstrated IC₅₀ (half maximal inhibitory concentration) value of 14.2 and 18.6 µg/ml, respectively, significantly lower than 42.4 µg/ml of curcumin and higher than 0.008 µg/ml of paclitaxel. Induction of apoptosis was evaluated in the terms of cleavage of caspase-3 enzyme and they also exhibited 69.6 and 65.4% of apoptosis significantly higher than 19.9% induced by curcumin. In conclusion, chloro and bromo derivatives must be evaluated under a set of stringent in vitro and in vivo parameters for translating in to a clinically viable product.

Communicated by Ramaswamy H. Sarma     

Decitabine augments cytotoxicity of cisplatin and doxorubicin to bladder cancer cells by activating hippo pathway through RASSF1A

During the past decade, microRNAs have continuously been suggested as a promising therapeutic tool due to their beneficial effects, such as their multi-targets and multi-functions in pathologic conditions. As a pathologic phenotype is generally regulated by multiple signaling pathways, in this study we identified a microRNA regulating multiple target genes within cardiac hypertrophic signaling pathways. microRNA-133a is known to play a crucial role in cardiac hypertrophy. However, the role of microRNA-133a, which may regulate several signaling pathways in norepinephrine-induced cardiac hypertrophy via multi-targeting, has not been investigated. In the current study, we showed that microRNA-133a can protect cardiomyocyte hypertrophy against norepinephrine stimulation in neonatal rat ventricular cardiomyocytes via new targets, PKCδ and Gq, all of which are related to downstream signaling pathways of the α₁-adrenergic receptor. Taken together, these results suggest the advantages of the therapeutic use of microRNAs as an effective potential drug regulating multiple signaling pathways under pathologic conditions.     

Preparation and characterization of magnetic gold nanoparticles to be used as doxorubicin nanocarriers

Magnetic targeted drug delivery (MTD), using magnetic gold nanoparticles (Fe₃O₄@Au NPs) conjugated with an anti-cancer drug is a promise modality for cancer treatment. In this study, Fe₃O₄@Au NPs were prepared and functionalized with thiol-terminated polyethylene glycol (PEG), then loaded with anti-cancer drug doxorubicin (DOX). The physical properties of the prepared NPs were characterized using different techniques. Transmission electron microscopy (TEM) revealed the mono dispersed nature of Fe₃O₄@Au NPs with an average size of 20 nm which was confirmed using Dynamic light scattering (DLS) measurements. Zeta potential measurements along with UV–VIS spectroscopy demonstrated surface DOX loading on Fe₃O₄@Au NPs. Energy Dispersive X-ray Spectroscopy (EDX) assured the existence of both iron and gold elements in the prepared NPs. The paramagnetic properties of the prepared NPs were assessed by vibrating sample magnetometer (VSM). The maximum DOX-loading capacity was 100 μg DOX/mg of Fe₃O₄@Au NPs. It was found that DOX released more readily at acidic pH. In vitro studies on MCF-7 cell line elucidated that DOX loaded Fe₃O₄@Au NPs (Fe₃O₄@Au-PEG-DOX) have more potent therapeutic effect than free DOX. Knowledge gained in this study may open the door to pursue Fe₃O₄@Au NPs as a viable nanocarriers for different molecules delivery in many diagnostic and therapeutic applications.