Anti-metastatic activity of biologically synthesized gold nanoparticles on human fibrosarcoma cell line HT-1080

Establishment of an amplification strategy - specific binding - convenient processing integrated aflatoxin B1 detection method based on Fe3O4-NH4/AuNPs/apt-S1

Aflatoxin B1 (AFB1) is a potent toxin in food, necessitating rapid, instant, and sensitive detection. We have engineered an electrochemical sensor to monitor AFB1 using a system composed of Fe3O4-NH4/AuNPs/apt-S1. The aptamer specifically recognizes AFB1, while 'S1' is functionalized with methylene blue to enhance the current. The RecJf exonuclease promotes the formation of the electrochemical strategy. The Fe3O4 component, with its magnet properties, enables a rapid separation of solids and liquids without the need for instrumentation. The sensor exhibits a linear range for AFB1 ranging from 1 ng to 10 μg. The regression equation is I(nA) = 446.8 × logc+2085 (where I and c represent the peak current and AFB1 concentration, respectively). The correlation coefficient is 0.9508, and the detection limit is 3.447 nM. The relative standard deviation of AFB1 in peanut oil ranges from 4.80% to 6.80%. These results demonstrate that the sensor has high sensitivity, stability, repeatability, and specificity for AFB1 detection.

Effect of gold-conjugated resveratrol nanoparticles on glioma cells and its underlying mechanism

BACKGROUND

 Glioblastoma is the most aggressive brain tumor with poor prognosis. Although Resveratrol (Rsv) is known to have therapeutic effects on glioma, the effects of gold-conjugated resveratrol nanoparticles (Rsv-AuNPs) on glioma cells are rarely reported.

OBJECTIVE

We aimed to investigate the effects of Rsv-AuNPs on glioma cells and its underlying mechanism.

METHOD

Human glioma cell line U87 was treated with different concentrations of Rsv-AuNPs. CCK-8, transwell, and wound healing assay were performed to measure the effects of Rsv-AuNPs on cell proliferation, invasion, and migration ability, respectively. Flow cytometry assay was used to detect the effects of Rsv-AuNPs on apoptosis. Changes of protein expressions related to proliferation, invasion, migration, and apoptosis were measured by Western blot assay. In addition, the inhibitory role of Rsv-AuNPs in the PI3K/AKT/mTOR signaling pathway was verified by using PI3K inhibitor LY294002.

RESULTS

Rsv-AuNPs treatment significantly suppressed proliferation, migration, and invasion of U87 cells (all P < 0.05) and increased the apoptosis rate (P < 0.05). The changes of proteins related to proliferation, migration, invasion and apoptosis were consistent (all P < 0.05). Moreover, Rsv-AuNPs treatment significantly inhibited the phosphorylation of PI3K, AKT and mTOR proteins in U87 cells (P < 0.05).

CONCLUSION

The present study found that Rsv-AuNPs inhibited the proliferation, migration, and invasion of U87 cells and induced apoptosis by inhibiting the activation of PI3K/AKT/mTOR signaling pathway. In the future, Rsv-AuNPs might be applied to the clinical treatment of glioma through more in-depth animal and clinical research.

Green Nanoformulations of Polyvinylpyrrolidone-Capped Metal Nanoparticles: A Study at the Hybrid Interface with Biomimetic Cell Membranes and In Vitro Cell Models

Noble metal nanoparticles (NP) with intrinsic antiangiogenic, antibacterial, and anti-inflammatory properties have great potential as potent chemotherapeutics, due to their unique features, including plasmonic properties for application in photothermal therapy, and their capability to slow down the migration/invasion speed of cancer cells and then suppress metastasis. In this work, gold (Au), silver (Ag), and palladium (Pd) NP were synthesized by a green redox chemistry method with the reduction of the metal salt precursor with glucose in the presence of polyvinylpyrrolidone (PVP) as stabilizing and capping agent. The physicochemical properties of the PVP-capped NP were investigated by UV-visible (UV-vis) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopies, dynamic light scattering (DLS), and atomic force microscopy (AFM), to scrutinize the optical features and the interface between the metal surface and the capping polymer, the hydrodynamic size, and the morphology, respectively. Biophysical studies with model cell membranes were carried out by using laser scanning confocal microscopy (LSM) with fluorescence recovery after photobleaching (FRAP) and fluorescence resonance energy transfer (FRET) techniques. To this purpose, artificial cell membranes of supported lipid bilayers (SLBs) made with 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine (POPC) dye-labeled with 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD, FRET donor) and/or lissamine rhodamine B sulfonyl (Rh, FRET acceptor) were prepared. Proof-of-work in vitro cellular experiments were carried out with prostate cancer cells (PC-3 line) in terms of cytotoxicity, cell migration (wound scratch assay), NP cellular uptake, and cytoskeleton actin perturbation.

Gold nanoparticles as antiangiogenic and antimetastatic agents

Angiogenesis and metastasis are two interdependent cancer hallmarks, the latter of which is the key cause of treatment failure. Thus, establishing effective antiangiogenesis/antimetastasis agents is the final frontier in cancer research. Gold nanoparticles (GNPs) may provide disruptive advancements in this regard due to their intrinsic physical and physiological features. Here, we comprehensively discuss recent potential therapeutical strategies to treat angiogenesis and metastasis and present a critical review on the state-of-the-art in vitro and in vivo evaluations of the antiangiogenic/antimetastatic activity of GNPs. Finally, we provide perspectives on the contribution of GNPs to the advancement of cancer management.

Green nanoparticles as multifunctional nanomedicines: Insights into anti-inflammatory effects, growth signaling and apoptosis mechanism in cancer

Recently, green nanotechnology got great attention due to their reliable, sustainable, and eco-friendly synthesis protocols. The green nanoparticles (GNPs) are preferred over chemically synthesized nanoparticles owing to less destructive effects associated with the synthesis procedures as well as therapeutic involvement. In this review, we have discussed the applications of GNPs in inflammation-mediated disorders, with special emphasis on cancer, initiated due to oxidative stress and inflammatory cascade. Real-time mechanism based studies on GNPs have suggested their anticancer effects through inducing apoptosis, inhibiting angiogenesis, tissue invasion metastasis, reduced replicative capabilities in addition to target specific different signaling molecules and cascades involved in the development or progression of cancer. Moreover, the association of GNPs with the inhibition or induction of autophagy for the management of cancer has also been discussed. A large number of studies showed the GNPs have multifunctional biomedical properties of theranostic prominence. Therefore, the development of GNPs with naturally established systems could upsurge their definite applications as biomedicines including target specific destruction of the cancerous cells.

Nanomaterial Technology and Soft Tissue Sarcomas

Soft tissue sarcomas (STSs) are relatively rare heterogeneous solid tumors of the mesenchymal origin. They account for approximately 1% of all malignant tumors in adults and have more than 70 histological subtypes. Consequently, the rarity and heterogeneity of STSs make their diagnosis and treatment very challenging. Nanotechnology has attracted increasing attention from researchers due to the unique physicochemical and biological properties of nanomaterials with potential medical applications as nanoprobes, drug delivery systems, photosensitizers, radioenhancers, antitumor agents, and their combinations for cancer diagnosis and treatment. This review discusses the progress made in the use of nanotechnology for the diagnosis and treatment of STSs and highlights future prospects of the STS multimodality therapy.

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

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

Modulatory Effects of Biosynthesized Gold Nanoparticles Conjugated with Curcumin and Paclitaxel on Tumorigenesis and Metastatic Pathways-In Vitro and In Vivo Studies

Background: Breast cancer is the most common cancer in women globally, and diagnosing it early and finding potential drug candidates against multi-drug resistant metastatic breast cancers provide the possibilities of better treatment and extending life. Methods: The current study aimed to evaluate the synergistic anti-metastatic activity of Curcumin (Cur) and Paclitaxel (Pacli) individually, the combination of Curcumin–Paclitaxel (CP), and also in conjugation with gold nanoparticles (AuNP–Curcumin (Au-C), AuNP–Paclitaxel (Au-P), and AuNP–Curcumin–Paclitaxel (Au-CP)) in various in vitro and in vivo models. Results: The results from combination treatments of CP and Au-CP demonstrated excellent synergistic cytotoxic effects in triple-negative breast cancer cell lines (MDA MB 231 and 4T1) in in vitro and in vivo mouse models. Detailed mechanistic studies were performed that reveal that the anti-cancer effects were associated with the downregulation of the expression of VEGF, CYCLIN-D1, and STAT-3 genes and upregulation of the apoptotic Caspase-9 gene. The group of mice that received CP combination therapy (with and without gold nanoparticles) showed a significant reduction in the size of tumor when compared to the Pacli alone treatment and control groups. Conclusions: Together, the results suggest that the delivery of gold conjugated Au-CP formulations may help in modulating the outcomes of chemotherapy. The present study is well supported with observations from cell-based assays, molecular and histopathological analyses.

Migration inhibition and selective cytotoxicity of cobalt hydroxide nanosheets on different cancer cell lines

5 nm-thick cobalt hydroxide nanosheets exhibited concentration-dependent selective antitumor activity and cell migration inhibition against a variety of cancer cells.

Green Synthesis of Gold Nanoparticles Using Plant Extracts as Beneficial Prospect for Cancer Theranostics

Gold nanoparticles (AuNPs) have been widely explored and are well-known for their medical applications. Chemical and physical synthesis methods are a way to make AuNPs. In any case, the hunt for other more ecologically friendly and cost-effective large-scale technologies, such as environmentally friendly biological processes known as green synthesis, has been gaining interest by worldwide researchers. The international focus on green nanotechnology research has resulted in various nanomaterials being used in environmentally and physiologically acceptable applications. Several advantages over conventional physical and chemical synthesis (simple, one-step approach to synthesize, cost-effectiveness, energy efficiency, and biocompatibility) have drawn scientists’ attention to exploring the green synthesis of AuNPs by exploiting plants’ secondary metabolites. Biogenic approaches, mainly the plant-based synthesis of metal nanoparticles, have been chosen as the ideal strategy due to their environmental and in vivo safety, as well as their ease of synthesis. In this review, we reviewed the use of green synthesized AuNPs in the treatment of cancer by utilizing phytochemicals found in plant extracts. This article reviews plant-based methods for producing AuNPs, characterization methods of synthesized AuNPs, and discusses their physiochemical properties. This study also discusses recent breakthroughs and achievements in using green synthesized AuNPs in cancer treatment and different mechanisms of action, such as reactive oxygen species (ROS), mediated mitochondrial dysfunction and caspase activation, leading to apoptosis, etc., for their anticancer and cytotoxic effects. Understanding the mechanisms underlying AuNPs therapeutic efficacy will aid in developing personalized medicines and treatments for cancer as a potential cancer therapeutic strategy.

Green Metallic Nanoparticles for Cancer Therapy: Evaluation Models and Cancer Applications

Metal-based nanoparticles are widely used to deliver bioactive molecules and drugs to improve cancer therapy. Several research works have highlighted the synthesis of gold and silver nanoparticles by green chemistry, using biological entities to minimize the use of solvents and control their physicochemical and biological properties. Recent advances in evaluating the anticancer effect of green biogenic Au and Ag nanoparticles are mainly focused on the use of conventional 2D cell culture and in vivo murine models that allow determination of the half-maximal inhibitory concentration, a critical parameter to move forward clinical trials. However, the interaction between nanoparticles and the tumor microenvironment is not yet fully understood. Therefore, it is necessary to develop more human-like evaluation models or to improve the existing ones for a better understanding of the molecular bases of cancer. This review provides recent advances in biosynthesized Au and Ag nanoparticles for seven of the most common and relevant cancers and their biological assessment. In addition, it provides a general idea of the in silico, in vitro, ex vivo, and in vivo models used for the anticancer evaluation of green biogenic metal-based nanoparticles.

Multifunctional Biodegradable Prussian Blue Analogue for Synergetic Photothermal/Photodynamic/Chemodynamic Therapy and Intrinsic Tumor Metastasis Inhibition

To date, various Prussian blue analogues (PBAs) have been prepared for biomedical applications due to their unique structural advantages. However, the safety and effectiveness of tumor treatment still need further exploration. This contribution reports a facile synthesis of PBA with superior tumor synergetic therapeutic effects and a detailed mechanistic evaluation of their intrinsic tumor metastasis inhibition activity. The as-synthesized PBA has a uniform cube structure with a diameter of approximately 220 nm and shows high near-infrared light (NIR) photoreactivity, photothermal conversion efficiency (41.44%), and photodynamic effect. Additionally, PBA could lead to a chemodynamic effect, which is caused by the Fenton reaction and ferroptosis. The combined therapy strategy of PBA exhibits notable tumor ablation properties due to photothermal therapy (PTT)/photodynamic therapy (PDT)/chemodynamic therapy (CDT) effects without obvious toxicity in vivo. The PBA has also shown potential as a contrast agent for magnetic resonance imaging (MRI) and photoacoustic (PA) imaging. More importantly, careful investigations reveal that PBA displays excellent biodegradation and anti-metastasis properties. Further exploration of the PBA implies that its underlying mechanism of intrinsic tumor metastasis inhibition activity can be attributed to the modulation of epithelial-mesenchymal transition (EMT) expression. The considerable potential exhibited by the as-synthesized PBA makes it an ideal candidate as a synergetic therapeutic agent for tumor treatment.

Modified Nanoparticles as Potential Agents in Bone Diseases: Cancer and Implant-Related Complications

Materials sized 1-100 nm are the nanotechnology's field of interest. Because of the unique properties such as the ability to penetrate biological barriers and a high surface to volume ratio, nanoparticles (NPs) are a powerful tool to be used in medicine and industry. This review discusses the role of nanotechnology in bone-related issues: osteosarcoma (bone cancer), the biocompatibility of the implants and implant-related infections. In cancer therapy, NPs can be used as (I) cytotoxic agents, (II) drug delivery platforms and (III) in thermotherapy. In implant-related issues, NPs can be used as (I) antimicrobial agents and (II) adjuvants to increase the biocompatibility of implant surface. Properties of NPs depend on (I) the type of NPs, (II) their size, (III) shape, (IV) concentration, (V) incubation time, (VI) functionalization and (VII) capping agent type.

Synthesis and characterization of gold nanoparticles from Marsdenia tenacissima and its anticancer activity of liver cancer HepG2 cells

Nowadays, the synthesis and characterization of gold nanoparticles (AuNPs) from plant based extracts and effects of their anticancer have concerned an important interest. Marsdenia tenacissima (MT), a conventional Chinese herbal medicine, has long been used for thousands of years to treat tracheitis, asthma, rheumatism, etc. In this present study, we optimize the reaction of parameters to manage the nanoparticle size, which was categorized by high-resolution transmission electron microscopy (HR-TEM). A different characterization method, for example, UV-visible spectroscopy (UV-vis), fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were performed to consider the synthesized AuNPs getting from the MT leaf extract. The MT-AuNPs were analyzed for their cytotoxicity property against HepG2 cells by MTT analysis. The apoptosis was evaluated by using reactive oxygen species (ROS), migration assay, mitochondrial membrane potential (MMP) and apoptotic protein expression. Interestingly, the findings of our study observed the cytotoxicity effect of synthesized MT-AuNPs at a concentration of 59.62 ± 4.37 μg after 24 hrs treatment. Apoptosis was induced by the MT-AuNPs with enhanced ROS, changed MMP and inhibit the migration assay. Finally, the apoptosis was confirmed by the considerable up-regulation of Bax, caspase-9 and caspase-3, while the anti-apoptotic protein expressions of Bcl-2 and Bcl-XL were down-regulated. Although, in this studies, we evaluated the characterization, synthesis and anticancer action of gold nanoparticles from MT (MT-AuNPS) helpful for liver cancer therapeutics.

Biogenic synthesis of silver nanoparticles using rhizome extract of Dysosma pleiantha and its antiproliferative effect against breast and human gastric cancer cells

Synthesis of biogenic metal nanoparticles using plant extract has gained considerable attention in recent years. The present study aims to synthesize and investigate the cytotoxic effect of silver nanoparticles (AgNPs) from Dysosma pleiantha rhizome extract. The green biosynthesis of AgNPs was verified by ultraviolet visible spectrometer, and characterized using fourier transform infrared spectroscopy, transmission electron microscopy and scanning electron microscopy. Results of microscopic studies revealed that the synthesized AgNPs were a spherical shape with an average size of 76 nm. We also examined the anti-cancer activity of biologically synthesized AgNPs. The dose-dependent cytotoxicity was observed in the breast cancer cell lines MDA-MB-231 and MDA-MB-453 treated with biogenically synthesized AgNPs, and the IC₅₀ was recorded at 33.521  and 36.25 µM respectively. The DNA fragmentation analysis showed that the MDA-MB-231 cells treated with increasing concentrations of AgNPs significantly triggered the fragmentation of DNA. In addition, the synthesized AgNPs exhibited dose dependent cytotoxic potential against human gastric cancer cell lines and the IC₅₀ was recorded at 7.14 µM. Thus, the green biosynthesized AgNPs from D. pleiantha rhizome can be used in the novel development of anticancer drugs.

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.

An investigation on the cytotoxicity and caspase-mediated apoptotic effect of biologically synthesized gold nanoparticles using Cardiospermum halicacabum on AGS gastric carcinoma cells

Background

Gastric cancer is the fourth most common cancer and second leading cause of cancer death worldwide. Cardiospermum halicacabum is used to treat nerve disorders, stiffness, rheumatism, ear ache, snake bite, and so on.

Methods

In this study, the reaction parameters were optimized to control the size of the nanoparticle, which was confirmed by transmission electron microscopy. Various characterization techniques such as selected area diffraction pattern, UV-visible spectroscopy, energy-dispersive X-ray analysis, dynamic light scattering, Fourier-transform infrared spectroscopy, and atomic force microscopy were employed to analyze the synthesized AuNPs obtained from C. halicacabum (CH-AuNP) against gastric carcinoma cell line.

Results

The cytotoxic effect of CH-AuNP against AGS, SNU-5, and SNU-16 cell lines was detected by MTT assay. The induction of apoptosis by CH-AuNP in AGS was analyzed by double staining technique using TUNEL and DAPI staining assays. Further to confirm the molecular mechanism exhibited by CH-AuNP to induce apoptosis, the intracellular ROS level was assessed and immunoblotting was performed to assess the apoptotic signaling molecules that often deregulated in cancerous condition.

Conclusion

The results clearly prove that CH-AuNP increases ROS and induces apoptosis in AGS, suggesting that CH-AuNP may be an effective anticancer drug with no side effects to treat gastric cancer.

Cytotoxicity of Plant-Mediated Synthesis of Metallic Nanoparticles: A Systematic Review

In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety of metallic nanoparticles used as anti-cancer agents remains a concern. The goal of this systematic review was to compare the cytotoxicity of different plant-mediated syntheses of metallic nanoparticles based on their potency, therapeutic index, and cancer cell type susceptibility in the hopes of identifying the most promising anti-cancer agents. A literature search of electronic databases including Science Direct, PubMed, Springer Link, Google Scholar, and ResearchGate, was conducted to obtain research articles. Keywords such as biosynthesis, plant synthesis, plant-mediated, metallic nanoparticle, cytotoxicity, and anticancer were used in the literature search. All types of research materials that met the inclusion criteria were included in the study regardless of whether the results were positive, negative, or null. The therapeutic index was used as a safety measure for the studied compound of interest. Data from 76 selected articles were extracted and synthesised. Seventy-two studies reported that the cytotoxicity of plant-mediated synthesis of metallic nanoparticles was time and/or dose-dependent. Biosynthesised silver nanoparticles demonstrated higher cytotoxicity potency compared to gold nanoparticles synthesised by the same plants (Plumbago zeylanica, Commelina nudiflora, and Cassia auriculata) irrespective of the cancer cell type tested. This review also identified a correlation between the nanoparticle size and morphology with the potency of cytotoxicity. Cytotoxicity was found to be inversely proportional to nanoparticle size. The plant-mediated syntheses of metallic nanoparticles were predominantly spherical or quasi-spherical, with the median lethal dose of 1⁻20 µg/mL. Nanoparticles with other shapes (triangular, hexagonal, and rods) were less potent. Metallic nanoparticles synthesised by Abutilon inducum, Butea monosperma, Gossypium hirsutum, Indoneesiella echioides, and Melia azedarach were acceptably safe as anti-cancer agents, as they had a therapeutic index of >2.0 when tested on both cancer cells and normal human cells. Most plant-mediated syntheses of metallic nanoparticles were found to be cytotoxic, although some were non-cytotoxic. The results from this study suggest a focus on a selected list of potential anti-cancer agents for further investigations of their pharmacodynamic/toxicodynamic and pharmacokinetic/toxicokinetic actions with the goal of reducing the Global Burden of Diseases and the second leading cause of mortality.

Polymer decorated gold nanoparticles in nanomedicine conjugates

Noble metal, especially gold nanoparticles and their conjugates with biopolymers have immense potential for disease diagnosis and therapy on account of their surface plasmon resonance (SPR) enhanced light scattering and absorption. Conjugation of noble metal nanoparticles to ligands specifically targeted to biomarkers on diseased cells allows molecular-specific imaging and detection of disease. The development of smart gold nanoparticles (AuNPs) that can deliver therapeutics at a sustained rate directly to cancer cells may provide better efficacy and lower toxicity for treating cancer tumors. We highlight some of the promising classes of targeting systems that are under development for the delivery of gold nanoparticles. Nanoparticles designed for biomedical applications are often coated with polymers containing reactive functional groups to conjugate targeting ligands, cell receptors or drugs. Using targeted nanoparticles to deliver chemotherapeutic agents in cancer therapy offers many advantages to improve drug/gene delivery and to overcome many problems associated with conventional radiotherapy and chemotherapy. The targeted nanoparticles were found to be effective in killing cancer cells which were studied using various anticancer assays. Cell morphological analysis shows the changes occurred in cancer cells during the treatment with AuNPs. The results determine the influence of particle size and concentration of AuNPs on their absorption, accumulation, and cytotoxicity in model normal and cancer cells. As the mean particle diameter of the AuNPs decreased, their rate of absorption by the intestinal epithelium cells increased. These results provide important insights into the relationship between the dimensions of AuNPs and their gastrointestinal uptake and potential cytotoxicity. Furthermore gold nanoparticles efficiently convert the absorbed light into localized heat, which can be exploited for the selective laser photothermal therapy of cancer. We also review the emerging technologies for the fabrication of targeted gold colloids as imagining agents.

Biocompatible 3D SERS substrate for trace detection of amino acids and melamine

A novel, low-cost and biocompatible three-dimensional (3D) substrate for surface-enhanced Raman spectroscopy (SERS) is fabricated using gold nanoparticles (AuNPs) loaded on cellulose paper for detection of amino acids and melamine. Dysosma pleiantha rhizome (Dp-Rhi) capped AuNPs (Dp-Rhi_AuNPs) were prepared by in situ using aqueous extract of Dp-Rhi and in situ functionalized Dp-Rhi on AuNPs surface was verified by Fourier transform infrared spectroscopy and zeta potentials analysis shows a negative (-18.4mV) surface charges, which confirm that presence of Dp-Rhi on AuNPs. The biocompatibility of Dp-Rhi_AuNPs is also examined by cell viability of FaDu cells using MTS assay and compared to control group. In conclusion, the SERS performance of AuNPs@cellulose paper substrates were systematically demonstrated and examined with different excitation wavelengths (i.e. 532, 632.8 and 785nm lasers) and the as-prepared 3D substrates provided an enhancement factor approaching 7 orders of magnitude compared with conventional Raman intensity using para-nitrothiophenol (p-NTP), para-aminothiophenol (p-ATP) and para-mercaptobenzoic acid (p-MBA) as probe molecules. The strong electromagnetic effect was generated at the interface of AuNPs and pre-treated roughened cellulose paper is also investigated by simulation in which the formation of possible Raman hot-spot zone in fiber-like microstructure of cellulose paper decorated with AuNPs. Notably, with optimized condition of as-prepared 3D AuNPs@cellulose paper is highly sensitive in the SERS detection of aqueous tyrosine (10^-10M) and melamine (10^-9M).

Lantana camara Linn root extract-mediated gold nanoparticles and their in vitro antioxidant and cytotoxic potentials

The Lantana camara Linn root extract derived gold nanoparticles (Au NPs) were characterized by Ultraviolet-Visible spectroscopy, X-ray diffraction, fourier transform-infrared, high resolution transmission electron microscopy, selected area electron diffraction pattern and energy dispersive X-ray analyses. In DPPH assay, the inhibitory concentration (IC₅₀) of Au NPs and gallic acid was 24.17 and 5.39 μg/ml, whereas, for cytotoxicity assay, the IC₅₀ of Au NPs was 17.72 and 32.98 μg/ml on MBA-MB-231 and Vero cells, respectively. Thus, the Au NPs possess significant in vitro antioxidant and cytotoxic properties which could be considered as potential alternate for the development of anticancer drug in future.

Biosynthesis of gold nanoparticles using green roof species Portulaca grandiflora and their cytotoxic effects against C6 glioma human cancer cells

Leaf and stem extracts of popular green roof vegetation, Portulaca grandiflora, were used for the synthesis of gold nanoparticles. The synthesized gold nanoparticles were characterized using UV–visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. FTIR results indicated the presence of proteins and polyphenols in plant extracts which were responsible for the reduction and stabilization of gold nanoparticles. SEM and TEM images confirmed the formation of spherical, rhombus, triangular, tetragonal, pentagonal, rods and hexagonal shaped gold nanoparticles. The size of the particles was in the range of 8 and 72 nm. The antiproliferative effects of synthesized gold nanoparticles were assessed using C6 glioma human cancer cells. Results indicated that gold nanoparticles synthesized using leaf extracts (150 µg/mL) and stem extracts (200 µg/mL) of P. grandiflora decreased the viability of C6 glioma cell lines up to 50%. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 1732–1740, 2016

Biosynthesis of gold nanoparticles: A green approach

Nanotechnology is an immensely developing field due to its extensive range of applications in different areas of technology and science. Different types of methods are employed for synthesis of nanoparticles due to their wide applications. The conventional chemical methods have certain limitations with them either in the form of chemical contaminations during their syntheses procedures or in later applications and use of higher energy. During the last decade research have been focussed on developing simple, clean, non-toxic, cost effective and eco-friendly protocols for synthesis of nanoparticles. In order to get this objective, biosynthesis methods have been developed in order to fill this gap. The biosynthesis of nanoparticles is simple, single step, eco-friendly and a green approach. The biochemical processes in biological agents reduce the dissolved metal ions into nano metals. The various biological agents like plant tissues, fungi, bacteria, etc. are used for biosynthesis for metal nanoparticles. In this review article, we summarised recent literature on biosynthesis of gold nanoparticles which have revolutionised technique of synthesis for their applications in different fields. Due to biocompatibility of gold nanoparticles, it has find its applications in biomedical applications. The protocol and mechanism of biosynthesis of gold nanoparticles along with various applications have also been discussed.

Gold-conjugated resveratrol nanoparticles attenuate the invasion and MMP-9 and COX-2 expression in breast cancer cells

Gold nanoparticles (AuNPs) with antitumorigenic effects obstruct the initiation, development and progression of tumors via the regulation of various processes, such as proliferation and apoptosis. However, the effects of AuNPs on breast cancer metastasis have not been well studied, and their response to 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulation remains unclear. Therefore, we synthesized resveratrol-capped gold nanoparticles (Rev-AuNPs) using green nanotechnology and investigated their potential anti-invasive properties in human breast cancer cells in response to TPA stimulation. The Rev-AuNPs formed spherical nanoparticles of 22.28±2.98 nm in diameter. Next, we found that non-cytotoxic concentrations of Rev-AuNPs significantly suppressed the TPA-induced migration and invasion abilities of breast cancer cells. Rev-AuNPs suppressed TPA-induced enzymatic activity and the expression of matrix metalloproteinase (MMP)-9 and cyclooxygenase-2 (COX-2). Furthermore, Rev-AuNP treatment remarkably downregulated TPA-induced nuclear translocation and transcriptional activation of nuclear transcription factor-κB (NF-κB) and activator protein-1 (AP-1). Rev-AuNPs reduced the phosphorylation of phosphoinositide 3-kinase/Akt (PI3K/Akt) and extracellular signal-regulated kinase (ERK)1/2 signaling, but did not affect the phosphorylation of Jun N-terminal kinase (JNK) or p38 MAPK in the TPA-stimulated breast cancer cells. Notably, Rev-AuNPs generally showed better anti-invasive activity than resveratrol without cytotoxicity. The inhibitory effect of Rev-AuNPs on MMP-9, COX-2, NF-κB, AP-1, PI3K/Akt and ERK activation was stronger than that of resveratrol for the same concentrations. We also demonstrated that Rev-AuNPs induced heme oxygenase-1 (HO-1) expression and that the inhibition of MMP-9 and COX-2 expression and MMP-9 enzymatic activity of Rev-AuNPs were abrogated by siRNA knockdown of HO-1 expression. Our findings revealed that the anti-invasive effects of Rev-AuNPs in response to TPA-stimulation were mediated by the suppression of MMP-9, COX-2, NF-κB, AP-1, PI3K/Akt and ERK and/or the activation of HO-1 signaling cascades. This novel finding emphasizes the pharmacological ability of Rev-AuNPs to treat breast cancer metastasis.

Green synthesis of therapeutic nanoparticles: an expanding horizon

Nanotechnology continues to achieve tremendous awards in therapeutics, but the economical and ecofriendly production of nanoparticles (NPs) is still in infancy, simply due to the nanotoxicity, unprecedented health hazards and scale up issues. Green nanotechnology was introduced in the quest to mitigate such risks by utilizing natural resources as biological tool for NP synthesis. The key advantages offered by green approach include lower capital and operating expenses, reduced environmental impacts, superior biocompatibility and higher stability. In this review, we shed light on the biosynthesis of therapeutic NPs along with their numerous biomedical applications. Toxicity aspects of NPs and the impact of green approach on it, is also discussed briefly.

Structural characterization, antioxidant and anticancer properties of gold nanoparticles synthesized from leaf extract(decoction)of Antigonon leptopus Hook. &Arn

Tea is an aromatic beverage prepared by pouring boiling water over alleviated leaves of the tea plant. Tea prepared from the aerial parts of Antigonon leptopus has been traditionally used as remedy for cold, diabetes and pain in many countries. The gold nanoparticles (Au NPs) synthesized from powdered leaf extract (decoction) of A. leptopus were characterized by UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) pattern and energy dispersive X-ray (EDX) analyses to define the formation of Au NPs. Further, the synthesized Au NPs were well characterized based on their strong surface plasmon resonance (SPR), crystalline nature, functional groups, size and dispersed shapes, purity and Bragg's reflections of face centered cubic (fcc) structure of metallic gold. The Au NPs showed higher free radical scavenging property when compared to the effect of leaf extract. Cytotoxicity study of synthesized Au NPs exhibited the growth inhibitory property at the concentration (GI50) of 257.8 μg/mL in human adenocarcinoma breast cancer (MCF-7) cells after 48 h. Thus, the Au NPs synthesized from the Mexican creeper, A. leptopus revealed the important biological properties: as a free radical as well as anticancer agent. We conclude that the A. leptopus derived biological materials have promising potential as a source for the development of anticancer drug in future.

Applications of biosynthesized metallic nanoparticles - a review

We present a comprehensive review of the applications of biosynthesized metallic nanoparticles (NPs). The biosynthesis of metallic NPs is the subject of a number of recent reviews, which focus on the various "bottom-up" biofabrication methods and characterization of the final products. Numerous applications exploit the advantages of biosynthesis over chemical or physical NP syntheses, including lower capital and operating expenses, reduced environmental impacts, and superior biocompatibility and stability of the NP products. The key applications reviewed here include biomedical applications, especially antimicrobial applications, but also imaging applications, catalytic applications such as reduction of environmental contaminants, and electrochemical applications including sensing. The discussion of each application is augmented with a critical review of the potential for continued development.

Acalypha indica Linn: Biogenic synthesis of silver and gold nanoparticles and their cytotoxic effects against MDA-MB-231, human breast cancer cells

This study reports the in vitro cytotoxic effect of biologically synthesized silver and gold nanoparticles against MDA-MB-231, human breast cancer cells. Formation of silver and gold nanoparticles was observed within 30 min and the various characterization techniques such as UV–vis spectrophotometer, FE-SEM, TEM and XRD studies were confirmed the synthesis of nanoparticles. Further, MTT, acridine orange and ethidium bromide (AO/EB) dual staining, caspase-3 and DNA fragmentation assays were carried out using various concentrations of silver and gold nanoparticles ranging from 1 to 100 μg/ml. At 100 μg/ml concentration, the plant extract derived nanoparticles exhibited significant cytotoxic effects and the apoptotic features were confirmed through caspase-3 activation and DNA fragmentation assays. Thus, the results of the present study indicate that biologically synthesized silver and gold nanoparticles might be used to treat breast cancer; however, it necessitates clinical studies to ascertain their potential as anticancer agents.

Dark-field microscopy in imaging of plasmon resonant nanoparticles

Dark-field microscopy (DFM) and spectroscopy base on localized surface plasmon resonance (LSPR) have been widely applied in biological sensing and single-molecule imaging. Using plasmonic nanoparticles with controlled geometrical, optical, and surface chemical properties as the probes, the scattering light depending on the surrounding environment can be detected by DF microscope. Signal-to-noise radio and time resolution of the conventional DFM is not sufficient to identify single molecular dynamics. To break these limitations, significant improvements have been made in recent years. This critical review is focused on the developments of the DFM and the utilization of DFM as a powerful technology in the application of LSPR detection.