Green sol–gel synthesis of hydroxyapatite nanoparticles using lemon extract as capping agent and investigation of its anticancer activity against human cancer cell lines (T98, and SHSY5)

Nanotechnology and biomedical sciences open the door to a wide range of biological research topics and medical applications at the molecular and cellular levels. Biosynthesis of nanoparticles has been proposed as a cost-effective and environmentally friendly alternative to chemical and physical methods. Plant-mediated synthesis of nanoparticles is a green chemistry approach that connects nanotechnology with plants. Novel methods of ideally synthesizing NPs are thus proposed that are formed at ambient temperatures, neutral pH, low costs and in an environmentally friendly fashion. The goal of the current study is to examine the cytotoxic activity of hydroxyapatite nanoparticles in various kinds of human cancer cells and potential mechanisms at play. Hydroxyapatite nanoparticles were created by the sol–gel method using lemon extract as a capping and reducing agent to achieve environmentally friendly synthesis. The synthesized nanoparticles were characterized by XRD, SEM, FTIR, TGA, VSM and HRTEM. They were tested for cytotoxicity against T98 and SH-SY5Y, two human cancer cell lines. The synthesized nanostructures significantly caused in vitro cell death in cancer cells. The results confirmed that synthesized nanoparticles significantly decreased the percentage of cells that survived. Nevertheless, it is essential to perform more investigations to find out the exact mechanisms involved. Binding energy of Hydroxyapatite- SH-S5YS complex and Hydroxyapatite- T98 complex calculated by molecular docking. However, it is essential to perform more investigations to find the underlying mechanisms.     

Synthesis,Chemical–Physical Characterization,and Biomedical Applications of Functional Gold Nanoparticles: A Review

Relevant properties of gold nanoparticles, such as stability and biocompatibility, together with their peculiar optical and electronic behavior, make them excellent candidates for medical and biological applications. This review describes the different approaches to the synthesis, surface modification, and characterization of gold nanoparticles (AuNPs) related to increasing their stability and available features useful for employment as drug delivery systems or in hyperthermia and photothermal therapy. The synthetic methods reported span from the well-known Turkevich synthesis, reduction with NaBH₄ with or without citrate, seeding growth, ascorbic acid-based, green synthesis, and Brust–Schiffrin methods. Furthermore, the nanosized functionalization of the AuNP surface brought about the formation of self-assembled monolayers through the employment of polymer coatings as capping agents covalently bonded to the nanoparticles. The most common chemical–physical characterization techniques to determine the size, shape and surface coverage of AuNPs are described underlining the structure–activity correlation in the frame of their applications in the biomedical and biotechnology sectors.     

Polymer-induced synthesis of stable gold and silver nanoparticles and subsequent ligand exchange in water

A simple, inexpensive, single-step synthesis of gold and silver nanoparticles using poly(allylamine) (PAAm) as a reducing and stabilizing agent is reported. The synthetic process was carried out in aqueous solution, making the method versatile and environmentally friendly. The synthesized polymer-stabilized nanoparticles are stable in water without particle aggregation at room temperature for at least a month. We demonstrate successful ligand exchange on the polymer-stabilized gold nanoparticles (AuNPs) with a variety of omega-functionalized acid-, alcohol-, amine-, and biotin-terminated alkylthiols. The methodologies, including ligand exchange, also are applicable for the generation of finely dispersed silver nanoparticles. The synthesized gold and silver nanoparticles are characterized by UV-visible absorption spectroscopy and transmission electron microscopy (TEM). The different ligand-stabilized AuNPs are also analyzed by Fourier transform infrared (FTIR) spectroscopy.     

Rapid synthesis of bovine serum albumin-conjugated gold nanoparticles using pulsed laser ablation and their anticancer activity on hela cells

Nanoscience research aims to produce nanoparticles without adverse effects for medical applications. The pulsed laser ablation (PLA) technique was utilized in this study to synthesize gold nanoparticles (AuNPs) using bovine serum albumin (BSA) in simulated body fluid (SBF) at the fundamental wavelength of the Nd: YAG laser (1064 nm). BSA acted as a stabilizer, reducing and capping agent to produce spherically shaped AuNPs (diameter 3–10 nm). The successful synthesis of AuNPs was confirmed through color changes and UV–vis spectroscopy. The agglomeration and precipitation of AuNPs are attributed to the presence of BSA in the solution, and electrostatic repulsion interactions between BSA and Au nanoclusters. The effect of salt concentration of SBF on BSA stability as well as the interaction of BSA conjugated AuNPs to form complexes was studied using molecular dynamic simulations. Our results show that the stability of AuNPs-BSA conjugates increase with the salt concentration of BSA. Moreover, the synthesized AuNPs exhibit low toxicity and high biocompatibility, supporting their application in drug delivery. Investigation of the cytotoxic effect of the synthesized AuNPs show that normal fibroblast cells (L929) remain intact after treatment whereas a dose-dependent inhibition effect on the growth of cervix cancer cells (HeLa) is observed. In general, this study presents an effective, environmentally-friendly, and facile approach to the synthesis of multifunctional AuNPs using the PLA technique, as a promising efficacious therapeutic treatment of cervical cancer.     

Synthesis of gold and silver nanoparticles using purified URAK

This study aims at developing a new eco-friendly process for the synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using purified URAK. URAK is a fibrinolytic enzyme produced by Bacillus cereus NK1. The enzyme was purified and used for the synthesis of AuNPs and AgNPs. The enzyme produced AgNPs when incubated with 1 mM AgNO3 for 24 h and AuNPs when incubated with 1 mM HAuCl4 for 60 h. But when NaOH was added, the synthesis was rapid and occurred within 5 min for AgNPs and 12 h for AuNPs. The synthesized nanoparticles were characterized by a peak at 440 nm and 550 nm in the UV-visible spectrum. TEM analysis showed that AgNPs of the size 60 nm and AuNPs of size 20 nm were synthesized. XRD confirmed the crystalline nature of the nanoparticles and AFM showed the morphology of the nanoparticle to be spherical. FT-IR showed that protein was responsible for the synthesis of the nanoparticles. This process is highly simple, versatile and produces AgNPs and AuNPs in environmental friendly manner. Moreover, the synthesized nanoparticles were found to contain immobilized enzyme. Also, URAK was tested on RAW 264.7 macrophage cell line and was found to be non-cytotoxic until 100 μg/ml.     

Potentials of phyto-fabricated nanoparticles as ecofriendly agents for photocatalytic degradation of toxic dyes and waste water treatment,risk assessment and probable mechanism

Nanotechnology is a promising field and has diverse applications. Primarily, nanoparticles have been synthesized via chemical and physical methods. Dyes are synthetic organic compounds that are abundantly used in industries especially in textile industry. The use of these dyes is major contributors towards environmental pollution. Their hazardous nature raises great concerns in general public. Advancement in nanotechnology can efficiently help in mitigating this problem as nanoparticles can efficiently convert these harmful dyes into less harmful chemical byproducts through a process called Photocatalysis. Although, different approaches have been used for the synthesis of nanoparticles and their Photocatalytic activity but the most efficient approach is the green synthesis using different plants. This approach is environment-friendly and cost-effective. In order to reduce the toxic effects of synthetic dyes that pollutes the environment, it is important to look for such environmental friendly approaches and highlight the role of green nanotechnology in photocatalysis. In the present review paper, we for the first time have summarized the application of biogenic nanoparticles used as Photocatalytic agent in the degradation of different dyes such MB, MO and MR. We have presented a comprehensive review of chemistry/engineering approach of the technology along with mechanistic aspects. Furthermore, key applications of nanotechnology in Photocatalysis have been discussed along with futuristic insight.     

Self-assembly of ionic liquid (BMI-PF6)-stabilized gold nanoparticles on a silicon surface: chemical and structural aspects

Ultrafine monodisperse gold nanoparticles (AuNPs) were synthesized by an elegant sputtering of gold onto 1- n-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF(6)) ionic liquid. It was found that the BMI-PF(6) supramolecular aggregates were loosely coordinated to the gold nanoparticles and were replaceable with thiol molecules. The self-assembly of BMI-PF(6)-stabilized AuNPs onto a (3-mercaptopropyl)trimethoxysilane (MPS)-functionalized silicon surface in 2D arrays, followed by dodecanethiol (DDT) treatment, have been demonstrated using X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and contact angle measurements. DDT treatment of tethered AuNPs revealed two types of interactions between AuNPs and the MPS-functionalized surface: (a) AuNPs anchor through Au-S chemisorption linkage resulting in strong immobilization and (b) some of the AuNPs are supported by physisorption, driven by BMI-PF(6). The attachment of these particles remains unchanged with sonication. The replacement of BMI-PF(6) aggregates from physisorbed AuNPs with DDT molecules advances the dilution of their interaction with the MPS-functionalized surface, and they subsequently detach from the silicon surface. The present finding is promising for the immobilization of ionic liquid-stabilized nanoparticles, which is very desirable for electronic and catalytic device fabrication. Additionally, these environmentally friendly AuNPs are expected to replace conventional citrate-stabilized AuNPs.     

Rapid synthesis of stable and functional conjugates of DNA/gold nanoparticles mediated by Tween 80

Gold nanoparticles conjugated with DNA represent an attractive and alternative platform for broad applications in biosensors, medical diagnostic, and biological analysis. However, current methods to conjugate DNA to gold nanoparticles are time-consuming. In this study, we report a novel approach to rapidly conjugate DNA to gold nanoparticles (AuNPs) to form functional DNA/AuNPs in 2-3 h using Tween 80 as protective agent. With a fluorescence-based technique, we determine that the DNA density on the surface of AuNPs achieves about ～60 strands per particles, which is comparable to the loading density in the current methods. Moreover, the DNA/AuNPs synthesized by our approach exhibit an excellent stability as a function of temperature, pH, and freeze-thaw cycle, and the functionality of DNA/AuNPs conjugates is also verified. The work presented here has important implications to develop the fast and reproducible synthesis of stable DNA-functionalized gold nanoparticles.     

Gold nanoparticles induced apoptosis via oxidative stress and mitochondrial dysfunctions in MCF‐7 breast cancer cells

Green synthesis of functionalized gold nanoparticles has been considered to be more biocompatible and has gained much attention in recent years. The eco‐friendly synthesis, long half‐life of drugs, low cost, and nontoxicity make them an appealing potential option for the biomedical field. The leaf aqueous extract of 10 different plants, namely, Araucaria heterophylla (Ah), Lagerstroemia indica (Li), Combretum indicum (Ci), Melia azedarach (Ma), Muntingia calabura (Mc), Hygrophila auriculata (Ha), Rivina humilis (Rh), Callistemon lanceolatus (Cl), Pterygota alata (Pa), and Vateria indica (Vi) was used for the synthesis of gold nanoparticles (AuNPs). Among them, six plants supported the synthesis of stable AuNPs. The generation of ruby red from pale yellow color proved AuNPs synthesis and which was further confirmed by the absorption peak in UV–Vis spectroscopy. Enhanced antioxidant activity was found with Pa–AuNPs compared with other phytosynthesized AuNPs. Pa–AuNPs were thus characterized by HR‐TEM, EDX, XRD, and FTIR. Pa–AuNPs exhibited potent dose‐dependent anticancer efficacy and an effective dose of IC₅₀ mediated apoptosis and necrosis in MCF‐7 breast cancer cells. Pa–AuNPs significantly enhanced the generation of ROS, in effect inducing mitochondrial membrane sensitization to trigger the cascade of apoptosis. The research highlights the effectiveness of AuNPs on cancer cells in vitro and, in turn, a progressive step toward novel biomedical applications. These findings indicate that phytosynthesized AuNPs may be an enticing anti‐cancer strategy for breast cancer without eliciting toxicity to normal cells.     

Synthesis of silver nanoparticles via green method using ultrasound irradiation in seaweed <Emphasis Type="Italic">Kappaphycus alvarezii</Emphasis> media

Green methods are a safer alternative to natural chemical and physical methods for the synthesis of silver nanoparticles (Ag-NPs), due to their being environmentally friendly and cost effective. This study offers a new green approach using ultrasound irradiation as the reducing agent and seaweed Kappaphycus alvarezii (K. alvarezii) as the natural bio-media. The seaweed K. alvarezii/Ag-NPs was characterised by ultraviolet–visible (UV–vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope with energy dispersive X-ray (FESEM-EDX), zeta potential, and Fourier transform infrared (FTIR) studies. UV–vis shows that surface plasmon resonance (SPR) arises from this solution due to the combined oscillations from the nanoparticles. The XRD study indicates the crystalline nature of the Ag-NPs. From the TEM images, the Ag-NPs are almost spherical with an average diameter of 11.78 nm. The FTIR spectrum provides adequate evidence of phytochemicals stabilising the nanoparticles. Synthesised Ag-NPs were successfully obtained using this green method.     

Synthesis,Characterization, and Applications of Copper Nanoparticles

Copper nanoparticles with different structural properties and effective biological effects may be fabricated using new green protocols. The control over particle size and in turn size-dependent properties of copper nanoparticles is expected to provide additional applications. Various methods for the synthesis of copper nanoparticles have been reported including chemical methods, physical methods, biological methods, and green synthesis. Biological methods involve the use of plant extracts, bacteria, and fungi. Commendable work has been done regarding the synthesis and stability of copper nanoparticles. There is a need to summarize the behavior of copper nanoparticles in different media under various conditions. Here, a complete list of the literature on the synthesis of copper nanoparticles, their properties, stabilizing agents, factors affecting the morphology, and their applications is presented. The importance of copper nanoparticles compared to other metal nanoparticles are due to high conductivity. Methods for the synthesis of copper nanoparticles, including green protocols using plants and micro-organisms compared chemical methods, have also been reviewed.     

KIT‐6 Mesoporous Silica‐coated Magnetite Nanoparticles: A Highly Efficient and Easily Reusable Catalyst for the Synthesis of Benzo[d]imidazole Derivatives

KIT‐6 mesoporous silica‐coated magnetite nanoparticles as highly ordered large‐pore nanoparticles supply an environmentally friendly procedure for the synthesis of benzo[d]imidazoles through condensation of 1,2‐diaminobenzene with aryl aldehydes. These compounds were obtained in high yields and short reaction times. The catalyst could be easily recovered using an external magnet and reused for six cycles with almost consistent activity. All of the synthesized compounds were characterized by their physical constant, comparison with authentic samples, ir, 1H nmr, 13C nmr spectroscopy, and elemental analysis.     

Green biosynthesis of gold nanoparticles using Croton sparsiflorus leaves extract and evaluation of UV protection,antibacterial and anticancer applications

Our study reports greener synthesis of gold nanoparticles (AuNPs) tethered to the extract of Croton sparsiflorus and in vitro evaluation of UV-protection, antibacterial and anticancer activities. Sophisticated instrumental analytical techniques such as UV–vis spectrophotometer, FT-IR, XRD, FE-SEM, and TEM were employed for the existence and confirmation of the nanoparticles. FT-IR and HPLC analysis were executed in the identification of the plausible functional groups implicated in the reduction of gold ions to AuNPs. UV protection property and antibacterial action of AuNPs-coated cotton fabric were also presented. Moreover, in vitro anticancer evaluation against HepG2 cell line was conducted by MTT assay for Croton sparsiflorus extract derived AuNPs in different concentrations (50 to 150 μg/ml). Thus, the results of this work revealed that greener synthesized AuNPs exhibited good therapeutic applications as UV-protection, antibacterial and anticancer agents.     

Regulation of the PI3K/AKT/mTOR signaling pathway with synthesized bismuth oxide nanoparticles from Ginger (Zingiber officinale) extract: Mitigating the proliferation of colorectal cancer cells

In order to overcome the limitations of conventional therapeutic systems in the treatment of cancer, nanoparticles (NPs) have been rapidly produced and developed as a separate treatment method for control of cancer. Synthesis of nanoparticles using plant-based materials (green synthesis), due to the easy and cost-effective synthesis, production of non-toxic, sustainable and environmentally friendly products, can be considered the most appropriate method for preparation of NPs. In this study, after synthesis of Bi₂O₃ NPs using Ginger (Zingiber officinale) root (rhizome) extract, the synthesized NPs were characterized and their potential application as selective anticancer agents against HCT116 colorectal cancer cells was evaluated through regulation of PI3K/AKT/mTOR signaling pathway, whereas the human kidney (HK-2) cells were used as normal cells. FTIR analysis showed a band at 673 cm^?1 attributed to Bi-O vibration with a fingerprint region at 1291 cm^?1 demonstrating the attachment of the organic molecules to the synthesized Bi₂O₃ NPs. UV–visible study showed a λ_max of around 268 nm, whereas XRD analysis showed eight clear peaks, demonetizing the crystalline phase of synthesized Bi₂O₃ NPs. TEM analysis showed that spherical-shaped Bi₂O₃ NPs have a size range of 20–50 nm with a man size of around 35 nm. Finally, DLS analysis determined that Bi₂O₃ NPs have a hydrodynamic size of about 71.19 nm (PDI of 0.179) and a zeta potential value of ?44.39 mV, revealing the good colloidal stability of NPs. Cellular assays (MTT, LDH, flow cytometry, and RT-qPCR) showed that synthesized Bi₂O₃ NPs selectively induced anticancer effects against HCT116 colorectal cancer cells through membrane leakage, generation of ROS, induction of apoptosis via dysregulation of Bax, Bcl-2 and caspase-3 at mRNA level mediated via regulation of PI3K/AKT/mTOR signaling pathway. In conclusion, it may be suggested that the presence study could provide useful information for the potential anticancer effects mediated by synthesized Bi₂O₃ NPs in vitro, although further studies, including in vivo studies and clinical trials, are needed to support our findings.     

Green synthesized AgNPs decorated on Ketjen black for enhanced catalytic dye degradation

Research on Chemical Intermediates - The green synthesis of nanoparticles using plant-based materials as an alternative to chemical and physical routes provides economic and environmental benefits....     

In Vitro Evaluation of Antibacterial and Antifungal Activity of Biogenic Silver and Copper Nanoparticles: The First Report of Applying Biogenic Nanoparticles against Pilidium concavum and Pestalotia sp. Fungi

There is increased attention paid to metallic nanoparticles due to their intensive use in various branches of agriculture and biotechnology, such as pest management, nanosensors, gene delivery, seed treatment, etc. There has been growing interest in applying environmentally friendly strategies for synthesizing nanoparticles without using substances which are hazardous to the environment. Biological practices for the synthesis of nanoparticles have been considered as possible ecofriendly alternatives to chemical synthesis. In the present study, we used biogenic silver and copper nanoparticles which were prepared by a previously reported green method. Moreover, the problem of chemical residues, which usually remain along with chemically synthesized nanoparticles and limit their application, was solved by developing such a green synthesis approach. To study the antibacterial activity of silver and copper nanoparticles, Pseudomonas aeruginosa was used; for the evaluation of antifungal activity, the pathogenic fungi Botrytis cinerea, Pilidium concavum and Pestalotia sp. were applied. To the best of our knowledge, this study represents the first time that the antifungal impact of a nanoparticle has been tested on Pilidium concavum and Pestalotia sp. Silver nanoparticles were found to be the more effective antimicrobial agent against all examined pathogens in comparison to copper nanoparticles. Data from such investigations provide valuable preliminary data on silver nanoparticle-based compounds or composites for use in the management of different pathogens.     

Catalytic Activity of Microbially‐formed Palladium Nanoparticles

The catalytic behavior of microbially‐formed palladium nanoparticles using Clostridium pasteurianum BC1 is reported. To our knowledge, this is the first study that evaluates the electrochemical catalytic activity of microbially‐formed palladium nanoparticles. Pd nanoparticles formed using immobilized microbes were found to exhibit an average mass activity of 177 mA mg⁻¹ which was almost twice the activity of the abiotically formed controls (94 mA mg⁻¹). The results of this study aim to support the use of nanoparticles formed using facile and environmentally‐friendly microbial synthesis methods as a suitable alternative as opposed to standard physical and chemical synthesis methods.     

Biogenic synthesis of gold and silver nanoparticles used in environmental applications: A review

Due to their physical, chemical, optical, and mechanical properties, metallic nanoparticles (MNPs) are increasingly being used, with an emphasis on silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs). In recent years, green synthesis has gained prominence for exploring the use of naturally available biological sources for the obtention of metallic nanoparticles. Among these, algae and plants stand out due to the presence of polysaccharides, proteins, polyphenols, and vitamins (among others) in their composition, which can act in the reduction and stabilisation of MNPs, and these biogenic materials have been characterised mainly by spectrometric and microscopic techniques. In addition, due to the numerous advantages of nanoparticles (NPs) synthetize from biogenic source, such as their simplicity and cost benefits, they have been used in the development of sensors applied in the determination of contaminants present in environmental samples and in the catalytic reduction of organic and inorganic contaminants. Therefore, this review describes the synthesis, mechanisms, characterization, and environmental analytical applications of NPs obtained by biogenic synthesis as well as the perspectives and challenges of these NPs.