Cytotoxicity and antimicrobial activities of green synthesized silver nanoparticles

Clinacanthus nutans crude polysaccharide extract as a green platform for microwave-assisted synthesis of silver nanoparticles: Optimization, characterization, and evaluation of bioactivities

Clinacanthus nutans (C. nutans) is a plant in tropical Asia with proven biological activities. The optimized extraction method of C. nutans crude polysaccharide (CNP) uses water in the presence of an ultrasound-assisted mechanical method (UL_CNP). However, the use of UL_CNP for the synthesis and optimization of silver nanoparticles (AgNP), particularly their anticancer and photocatalytic properties, remains unexplored. Hence, this research aimed to employ a green method using UL_CNP and silver nitrate to produce AgNP (UL_AgNP) with a small size and assess its potential toxicity, anticancer, and photocatalytic activities. The synthesis condition was optimized using the Box-Behnken design method. The synthesized UL_AgNP showed the surface plasmon resonance peak at 458 nm. The optimized synthesis condition produced spherically shaped UL_AgNP with a size of 5.21 ± 1.92 nm and a zeta potential of -26.33 ± 0.93 mV. An X-ray diffraction analysis exhibited intense Bragg's reflection peaks at (111), (200), (220), and (311), having a face-centered cubic structure of AgNP. Attenuated total reflectance-Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy further confirmed the presence of silver in the synthesized UL_AgNP. The brine shrimp lethality test of UL_AgNP reported a lethal concentration 50 value of <7.8 μg/mL after 24 h. The UL_AgNP exhibited antiproliferative activity against MCF-7 cells with a half-maximal inhibitory concentration value of 4.96 ± 0.31 μg/mL by inducing S-phase cell cycle arrest, apoptotic effect, and reduction of cell migration. Furthermore, UL_AgNP proved its efficient photocatalytic activity against methylene blue dye (50.22 % ± 0.06 %, after 10 min at a concentration of 50 μg/mL). Therefore, the UL_AgNP exhibited promising antiproliferative activity against MCF-7 cells, highlighting their potential as a therapeutic agent. Further investigations are needed to elucidate the precise mechanism of their action.

Characterization and Biomedical Applications of Green-Synthesized Selenium Nanoparticles Using Tridax procumbens Stem Extract

Background Selenium nanoparticles (SeNPs) are one of the metal nanoparticles that have been widely utilized for their anti-microbial, anti-oxidant, anti-inflammatory activities, and other biomedical applications. Tridax procumbens (TP) stem extract is a promising herb species rich in flavonoids, tannins, alkaloids, phytosterols, and hydroxycinnamates, which play a major role in wound healing applications.  Aim The study aims to synthesize SeNPs using TP stem extract, characterizations, and its biomedical applications. Materials and methods SeNPs were synthesized using TP stem extract. The green synthesis of SeNPs was confirmed by ultraviolet-visible (UV-vis) spectra analysis. The synthesized SeNPs were characterized using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The agar well diffusion method was utilized to evaluate the anti-bacterial properties of the green synthesized SeNPs using TP stem extract. The anti-oxidant effect of SeNPs was tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, ferric-reducing anti-oxidant power assay (FRAP), and hydroxyl radical scavenging assay (H₂O₂). The anti-inflammatory effect was investigated using the bovine serum albumin assay and egg albumin denaturation method, and the cytotoxic effect of the green synthesized SeNPs was tested using the brine shrimp lethality (BSL) assay. Results The green synthesis of SeNPs was confirmed using different types of analysis techniques. The characterizations were done by UV-visible spectroscopy analysis, exhibiting a maximum peak at the range of 330 nm. SEM analysis revealed the shape of the nanoparticle to be hexagonal. The agar well diffusion method exhibited the anti-bacterial efficacy of SeNPs against wound microorganisms with a zone of inhibition of 14.6 mm for Escherichia coli (E. coli), 15.8 mm for Staphylococcus aureus (S. aureus), and 15.4 mm for Pseudomonas aeruginosa (P. aeruginosa). The TP stem-mediated SeNPs showed potential effects in anti-oxidant, anti-inflammatory, and cytotoxic activity, which shows very little toxicity. Conclusion Overall, the green synthesis of TP-stem-mediated SeNPs has great potential in biomedical applications. Thus, the synthesized SeNPs exhibit significant anti-bacterial efficacy against wound pathogens. The TP stem-mediated SeNPs showed potential effects in anti-oxidant, anti-inflammatory, and cytotoxic activity, which shows low toxicity. Furthermore, the green-synthesized SeNPs can be utilized in therapeutic management.

Synthesis of Silver Nanoparticles Using Camellia sinensis Leaf Extract: Promising Particles for the Treatment of Cancer and Diabetes

Both diabetes and cancer pose significant threats to public health. To overcome these challenges, nanobiotechnology offers innovative solutions for the treatment of these diseases. However, the synthesis of nanoparticles can be complex, costly and environmentally toxic. Therefore, in this study, we successfully synthesized Camellia sinensis silver nanoparticles (CS-AgNPs) biologically from methanolic leaf extract of C. sinensis and as confirmed by the visual appearance which exhibited strong absorption at 456 nm in UV-visible spectroscopy. The fourier transform infrared spectroscopy (FTIR) analysis revealed that phytochemicals of C. sinensis were coated with AgNPs. Scanning electron microscopy (SEM) analysis showed the spherical shape of CS-AgNPs, with a size of 15.954 nm, while X-ray diffraction spectrometry (XRD) analysis detected a size of 20.32 nm. Thermogravimetric analysis (TGA) indicated the thermal stability of CS-AgNPs. The synthesized CS-AgNPs significantly inhibited the ehrlich ascites carcinoma (EAC) cell growth with 53.42±1.101 %. The EAC cell line induced mice exhibited increased level of the serum aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), however this elevated serum parameter significantly reduced and controlled by the treatment with CS-AgNPs. Moreover, in a streptozotocin-induced diabetic mice model, CS-AgNPs greatly reduced blood glucose, total cholesterol, triglyceride, low-density lipoprotein (LDL) and creatinine levels. These findings highlight that the synthesized CS-AgNPs have significant anticancer and antidiabetic activities that could be used as promising particles for the treatment of these major diseases. However, pre-clinical and clinical trial should be addressed before use this particles as therapeutics agents.

Thespesia lampas mediated green synthesis of silver and gold nanoparticles for enhanced biological applications

The present study investigated the synthesis and biological applications of green, economical, and multifunctional silver and gold nanoparticles (TSAgNPs and TSAuNPs) using the ethnomedical important medicinal plant Thespesia lampas for biological activities. Relatively higher levels of antioxidant components were measured in T. lampas compared to the well-known Adhatoda vasica, and Diplocyclos palmatus suggested the potential of T. lampas for the study. Synthesized TSAgNPs and TSAuNPs were characterized through UV-Vis, XRD, SEM-EDS, HR-TEM, SAED, and FTIR techniques. SEM revealed that TSAgNPs and TSAuNPs were predominantly spherical in shape with 19 ± 7.3 and 43 ± 6.3 nm crystal sizes. The sizes of TSAgNPs and TSAuNPs were found to be12 ± 4.8 and 45 ± 2.9 nm, respectively, according to TEM measurements. The FTIR and phytochemical analyses revealed that the polyphenols and proteins present in T. lampas may act as bio-reducing and stabilizing agents for the synthesis. Synthesized NPs exhibited enhanced scavenging properties for ABTS and DPPH radicals. TSAgNPs and TSAuNPs were able to protect DNA nicking up to 13.48% and 15.38%, respectively, from oxidative stress. TSAgNPs possessed efficient antibacterial activities in a concentration-dependent manner against human pathogenic bacteria, such as E. coli, B. subtilis, P. vulgaris, and S. typhi. Furthermore, TSAgNPs and TSAuNPs showed significant cytotoxicity against FaDu HNSCC grown in 2D at 50 and 100 μg mL-1. Tumor inhibitory effects on FaDu-derived spheroid were significant for TSAgNPs > TSAuNPs at 100 μg mL-1 in 3D conditions. Dead cells were highest largely for TSAgNPs (76.65% ± 1.76%), while TSAuNPs were non-significant, and Saq was ineffectively compared with the control. However, the diameter of the spheroid drastically reduced for TSAgNPs (3.94 folds) followed by TSAuNPs (2.58 folds), Saq (1.94 folds), and cisplatin (1.83 folds) at 100 μg mL-1. The findings of the study suggested the bio-competence of TSAgNPs and TSAuNPs as multi-responsive agents for antioxidants, DNA protection, antibacterial, and anti-tumor activities to provide a better comprehension of the role of phytogenic nanoparticles in healthcare systems.

Bio-Fabricated Silver Nanoparticles from the Leaf Extract of the Poisonous Plant, Holigarna arnottiana: Assessment of Antimicrobial, Antimitotic, Anticancer, and Radical-Scavenging Properties

This study presents a novel approach to fabricate silver nanoparticles (AgNPs) using the poisonous plant, Holigarna arnottiana leaf extract. The formation of AgNPs was confirmed by a color change from green to dark brown and validated by UV analysis. FTIR analysis identified functional groups on the AgNPs, while Zeta potential analysis assessed their stability. TEM analysis established an average diameter of 18 nm and a spherical morphology for the nanoparticles. LC MS analysis coupled with database searches revealed the presence of diverse bioactive compounds, including flavonoids, nucleotides, dipeptides, enzymes, and glycosides. These compounds are postulated to act as reducing agents in the leaf extract-mediated synthesis process. Moreover, the bio-fabricated AgNPs exhibited noteworthy anticancer properties against DLA cells. In addition, AgNPs displayed substantial antimitotic effects in an assay involving Allium cepa root cells. These findings underscore the potential of the AgNPs as cytotoxic agents. The biosynthesized AgNPs showed antimicrobial activity against various bacterial pathogens, including Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus. Furthermore, the AgNPs exhibited outstanding radical-scavenging properties in the DPPH assay, suggesting their potential application in antioxidant therapies. The study collectively highlights the successful synthesis of AgNPs through a green, biocompatible approach, and demonstrates their promising potential for anticancer, antimitotic, and radical-scavenging applications.

Current Trends and Prospects for Application of Green Synthesized Metal Nanoparticles in Cancer and COVID-19 Therapies

Cancer and COVID-19 have been deemed as world health concerns due to the millions of lives that they have claimed over the years. Extensive efforts have been made to develop sophisticated, site-specific, and safe strategies that can effectively diagnose, prevent, manage, and treat these diseases. These strategies involve the implementation of metal nanoparticles and metal oxides such as gold, silver, iron oxide, titanium oxide, zinc oxide, and copper oxide, formulated through nanotechnology as alternative anticancer or antiviral therapeutics or drug delivery systems. This review provides a perspective on metal nanoparticles and their potential application in cancer and COVID-19 treatments. The data of published studies were critically analysed to expose the potential therapeutic relevance of green synthesized metal nanoparticles in cancer and COVID-19. Although various research reports highlight the great potential of metal and metal oxide nanoparticles as alternative nanotherapeutics, issues of nanotoxicity, complex methods of preparation, biodegradability, and clearance are lingering challenges for the successful clinical application of the NPs. Thus, future innovations include fabricating metal nanoparticles with eco-friendly materials, tailor making them with optimal therapeutics for specific disease targeting, and in vitro and in vivo evaluation of safety, therapeutic efficiency, pharmacokinetics, and biodistribution.

Antimicrobial, anticancer and immunomodulatory potential of new quinazolines bearing benzenesulfonamide moiety

Sulfonamides are privileged candidates with potent anti-methicillin-resistant Staphylococcus aureus (MRSA) activity and could replenish the MRSA antibiotic pipeline. The initial screening of a series of quinazolinone benzenesulfonamide derivatives 5-18 against multidrug-resistant bacterial and fungal strains revealed their potent activity. The promising compounds were conjugated with ZnONPs to study the effect of nanoparticle formation on the antimicrobial, cytotoxic and immunomodulatory activity. Compounds 5, 11, 16 and 18 revealed promising antimicrobial and cytotoxic activities with superior safety profiles and enhanced activity upon nanoformulation. The immunomodulatory potential of compounds 5, 11, 16 and 18 was assessed. Compounds 5 and 11 demonstrated an increase in spleen and thymus weight and boosted the activation of CD4⁺ and CD8⁺ T lymphocytes, confirming their promising antimicrobial, cytotoxic and immunomodulatory activity.

Alleviating the adverse effects of salinity on Roselle plants by green synthesized nanoparticles

In the present study, an eco-friendly process was made for the rapid synthesis of silver nanoparticles using aqueous leaf extract of Hibiscus sabdariffa. The process was characterized by Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible and X-ray diffraction (XRD). These green silver nanoparticles (NPs) were used for mitigating the adverse effects of salinity on seed germination and growth parameters in plants. Accordingly, two experiments were conducted. In the first experiment, seven concentrations of green silver NPs and nine levels of NaCl:CaCl were apptoed on seeds for germination, and their effects were evaluated. In the second experiment, three concentrations of green silver NPs and NaCl were hypothesized to affect plant growth parameters. Seed germination, plant height, leaf, and root fresh and dry weights, as well as relative water content (RWC), decreased significantly under salt stress. However, green silver NPs intervened by alleviating the adverse effects of stress. Accordingly, green silver NPs were beneficial due to (1) activation of the antioxidant system by enhancing antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), and superoxide dismutase (SOD); (2) increase in the amounts of proline, soluble sugars and carbohydrates for osmoprotection; (3) improvements in flavonoid and anthocyanin contents. Real-time PCR showed that flavonoid and anthocyanin contents increased because of higher expressions in chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), and anthocyanidin synthase (ANS) genes. In conclusion, green silver NPs offered an eco-friendly application for further research on agricultural development.

Synthesis and Adsorbent Performance of Modified Biochar with Ag/MgO Nanocomposites for Heat Storage Application

Heat storage is a major problem in the world. Many research is going on the heat storage application. This research investigates the novel Ag/MgO/biochar nanocomposites for heat storage. Ag/MgO/biochar nanocomposites were fabricated using solvent-free ball milling techniques. According to several analytical measurements, the Ag/MgO nanoparticles in biochar are uniformly dispersed across the carbon interface. This type of adsorbent material has been characterized by different techniques such as X-ray diffraction pattern analysis (XRD), FTIR analysis, scanning electron microscope (SEM), and transmission electron microscope (TEM) as all indicate the surface morphology and successful ball milling synthesis of Ag/MgO nanocomposites. The UV visible spectroscopy wavelength range of AgNPs and MgONPs is 330 nm and 470 nm, respectively. FTIR analysis revealed that different functional groups of modified biochar nanocomposites such as O-H group are 3728 cm-1 and for C-H bond is 932 cm-1, C-O group is 1420 cm-1, and C=O is 1785 cm-1, respectively. Adsorption tests showed that 1.0 gL-1 dosage with 60% phosphate removal, an ion, and 0.2 gL-1 of dosages that had 85% methylene blue decomposition, a charged synthetic dye, were the lowest absorption levels. This research suggests that ball milling offers the advantages of stabilization and chemical adaptability for customized remediation of different atmospheric contaminants. Ball milling is a facile and feasible process to fabricate carbon-metal-oxide nanomaterials.

Recent Advances in Silver Nanoparticles Containing Nanofibers for Chronic Wound Management

Infections are the primary cause of death from burns and diabetic wounds. The clinical difficulty of treating wound infections with conventional antibiotics has progressively increased and reached a critical level, necessitating a paradigm change for enhanced chronic wound care. The most prevalent bacterium linked with these infections is Staphylococcus aureus, and the advent of community-associated methicillin-resistant Staphylococcus aureus has posed a substantial therapeutic challenge. Most existing wound dressings are ineffective and suffer from constraints such as insufficient antibacterial activity, toxicity, failure to supply enough moisture to the wound, and poor mechanical performance. Using ineffective wound dressings might prolong the healing process of a wound. To meet this requirement, nanoscale scaffolds with their desirable qualities, which include the potential to distribute bioactive agents, a large surface area, enhanced mechanical capabilities, the ability to imitate the extracellular matrix (ECM), and high porosity, have attracted considerable interest. The incorporation of nanoparticles into nanofiber scaffolds constitutes a novel approach to “nanoparticle dressing” that has acquired significant popularity for wound healing. Due to their remarkable antibacterial capabilities, silver nanoparticles are attractive materials for wound healing. This review focuses on the therapeutic applications of nanofiber wound dressings containing Ag-NPs and their potential to revolutionize wound healing.

Phytofabrication of bimetallic silver-copper/biochar nanocomposite for environmental and medical applications

In the current study, a novel, green, low-cost, and sustainable path for the phyto-fabrication of Ag-Cu biochar nanocomposite (Ag-Cu/biochar) by Atriplex halimus biomass and aqueous extract is described. Surface plasmon resonance peaks were detected at 450 nm and 580 nm signifying the formation of both silver and copper nanoparticles, respectively on the biochar surface. XRD analysis confirmed the crystal structure of the phytosynthesized Ag-Cu/biochar whereas FT-IR, SEM, EDX, and XPS analyses confirmed the successful phytofabrication of the composite. Ag and Cu nanoparticles loaded on the biochar surface were almost spherically-shaped with a particle size ranging from 25 nm to 45 nm. Zeta potential of -25.5 mV showed the stability of Ag-Cu/biochar. The potential of this novel nanocomposite in the removal of doxycycline (DOX) was evident under different conditions as it reached nearly 100% under the optimum reaction conditions (DOX concentration; 50 ppm, pH; 9, a dose of Ag-Cu/biochar; 0.01 g, temperature; 25 °C, and H₂O₂ concentration; 100 mM). The promising regeneration of Ag-Cu/biochar was evident as the removal efficiency was 81% after 6 consecutive cycles. Ag-Cu/biochar was also shown an excellent antimicrobial activity against gram-negative bacteria as well a promising antioxidant activity.

Green Synthesis and Characterization of Antimicrobial Synergistic AgCl/BAC Nanocolloids

All over the world, one of the major challenges is the green synthesis of potential materials against antimicrobial resistance and viruses. This study demonstrates a simple method like chemistry lab titration to synthesize green, facile, scalable, reproducible, and stable synergistic silver chloride/benzyldimethylhexadecyl-ammonium chloride (AgCl/BAC) colloidal Nanoantimicrobials (NAMs). Nanocolloidal dispersions of AgCl in an aqueous medium are prepared by using silver nitrate (AgNO₃) as precursor and BAC as both sources of chloride and stabilizer, holding an asymmetric molecular structure. The synthetic approach is scalable and green. Both the morphology and stability of AgCl/BAC nanocolloids (NCs) were investigated as a function of different molar fractions of the reagents. AgCl/BAC NCs were characterized by transmission electron microscopy (TEM) and X-ray photoelectron and UV–vis spectroscopies. Zeta potential measurements revealed increasing positive potential values at every stage of the synthesis. Size distribution and hydrodynamic diameter of the particles were measured by dynamic light scattering (DLS), which predicted the formation of BAC layered structures associated with the AgCl nanoparticles (NPs). Small-angle X-ray scattering (SAXS) experiments verify the thickness of the BAC bilayer around AgCl. The produced AgCl/BAC NCs probably have synergistic antimicrobial properties from the AgCl core and the biocide BAC shell. AgCl/BAC NCs stability over months was investigated. The experimental evidence supports the morphological stability of the AgCl/BAC NCs, while higher positive zeta potential values anticipate a long-term antimicrobial effect: a higher surface charge causes NPs to be potentially more lethal to bacteria. AgCl/BAC antimicrobial aqueous colloidal suspensions will be used as additives for the industrial production of antimicrobial coatings.

Green synthesis of bimetallic Ag/ZnO@Biohar nanocomposite for photocatalytic degradation of tetracycline, antibacterial and antioxidant activities

In this work, a simple and green synthesis procedure for phytofabrication Zinc oxide-silver supported biochar nanocomposite (Ag/ZnO@BC) via Persicaria salicifolia biomass is investigated for the first time to uphold numerous green chemistry such as less hazardous chemical syntheses. XRD technique showed the crystal structure of the phytosynthesized Ag/ZnO@BC, whereas UV-visible spectroscopy, FT-IR, SEM, EDX, TEM, and XPS analyses indicated the successful biosynthesis of the nanocomposite. Testing the photocatalytic potential of this novel nanocomposite in the removal of TC under different conditions unraveled its powerful photodegradation efficiency that reached 70.3% under the optimum reaction conditions: TC concentration; 50 ppm, pH; 6, a dose of Ag/ZnO@BC; 0.01 g, temperature; 25 °C, and H₂O₂ concentration; 100 mM. The reusability of Ag/ZnO@BC was evident as it reached 53% after six cycles of regeneration. Ag/ZnO@BC was also shown to be a potent antimicrobial agent against Klebsiella pneumonia as well as a promising antioxidant material. Therefore, the current work presented a novel nanocomposite that could be efficiently employed in various environmental and medical applications.

Green-Synthesized Silver Nanoparticle-Assisted Radiofrequency Ablation for Improved Thermal Treatment Distribution

Thermal ablation therapy is known as an advantageous alternative to surgery allowing the treatment of multiple tumors located in hard-to-reach locations or treating patients with medical conditions that are not compatible with surgery. Appropriate heat propagation and precise control over the heat propagation is considered a weak point of thermal ablation therapy. In this work, silver nanoparticles (AgNPs) are used to improve the heat propagation properties during the thermal ablation procedure. Green-synthesized silver nanoparticles offer several attractive features, such as excellent thermal conductivity, biocompatibility, and antimicrobial activity. A distributed multiplexed fiber optic sensing system is used to monitor precisely the temperature change during nanoparticle-assisted radiofrequency ablation. An array of six MgO-based nanoparticles doped optical fibers spliced to single-mode fibers allowed us to obtain the two-dimensional thermal maps in a real time employing optical backscattering reflectometry at 2 mm resolution and 120 sensing points. The silver nanoparticles at 5, 10, and 20 mg/mL were employed to investigate their heating effects at several positions on the tissue regarding the active electrode. In addition, the pristine tissue and tissue treated with agarose solution were also tested for reference purposes. The results demonstrated that silver nanoparticles could increase the temperature during thermal therapies by propagating the heat. The highest temperature increase was obtained for 5 mg/mL silver nanoparticles introduced to the area close to the electrode with a 102% increase of the ablated area compared to the pristine tissue.

Gums-based engineered bio-nanostructures for greening the 21st-century biotechnological settings

Naturally occurring plant-based gums and their engineered bio-nanostructures have gained an immense essence of excellence in several industrial, biotechnological, and biomedical sectors of the modern world. Gums derived from bio-renewable resources that follow green chemistry principles are considered green macromolecules with unique structural and functional attributes. For instance, gum mostly obtained as exudates are bio-renewable, bio-degradable, bio-compatible, sustainable, overall cost-effective, and nontoxic. Gum exudates also offer tunable attributes that play a crucial role in engineering bio-nanostructures of interest for several bio- and non-bio applications, e.g., food-related items, therapeutic molecules, sustained and controlled delivery cues, bio-sensing constructs, and so on. With particular reference to plant gum exudates, this review focuses on applied perspectives of various gums, i.e., gum Arabic, gum albizzia, gum karaya, gum tragacanth, and gum kondagogu. After a brief introduction with problem statement and opportunities, structural and physicochemical attributes of plant-based natural gums are presented. Following that, considerable stress is given to green synthesis and stabilization of gum-based bio-nanostructures. The final part of the review focuses on the bio- and non-bio related applications of various types of gums polysaccharides-oriented bio-nanostructures.

HRMS Characterization, Antioxidant and Cytotoxic Activities of Polyphenols in Malus domestica Cultivars from Costa Rica

There is increasing interest in research into fruits as sources of secondary metabolites because of their potential bioactivities. In this study, the phenolic profiles of Malus domestica Anna and Jonagold cultivars from Costa Rica were determined by Ultra Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry (HRMS) using a quadrupole-time-of-flight analyzer (UPLC-QTOF-ESI MS), on enriched-phenolic extracts from skins and flesh, obtained through Pressurized Liquid Extraction (PLE). In total, 48 different phenolic compounds were identified in the skin and flesh extracts, comprising 17 flavan-3-ols, 12 flavonoids, 4 chalcones, 1 glycosylated isoprenoid and 14 hydroxycinnamic acids and derivatives. Among extracts, the flesh of Jonagold exhibits a larger number of polyphenols and is especially rich in procyanidin trimers, tetramers and pentamers. Evaluating total phenolic content (TPC) and antioxidant activities using ORAC and DPPH procedures yields higher values for this extract (608.8 mg GAE/g extract; 14.80 mmol TE/g extract and IC50 = 3.96 µg/mL, respectively). In addition, cytotoxicity evaluated against SW620 colon cancer cell lines and AGS gastric cancer cell lines also delivered better effects for Jonagold flesh (IC50 = 62.4 and 60.0 µg/mL, respectively). In addition, a significant negative correlation (p < 0.05) was found between TPC and cytotoxicity values against SW620 and AGS adenocarcinoma (r = -0.908, and -0.902, respectively). Furthermore, a significant negative correlation (p < 0.05) was also found between the number of procyanidins and both antioxidant activities and cytotoxicity towards SW620 (r = -0.978) and AGS (r = -0.894) cell lines. These results align with Jonagold flesh exhibiting the highest abundance in procyanidin oligomers and yielding better cytotoxic and antioxidant results. In sum, our findings suggest the need for further studies on these Costa Rican apple extracts-and particularly on the extracts from Jonagold flesh-to increase the knowledge on their potential benefits for health.

Comparative assessment of the fate and toxicity of chemically and biologically synthesized silver nanoparticles to juvenile clams

Nanoparticles (NPs) can be produced via physical, chemical, or biological approaches. Yet, the impact of the synthesis approaches on the environmental fate and effects of NPs is poorly understood. Here, we synthesized AgNPs through chemical and biological approaches (cit-AgNPs and bio-AgNPs), characterized their properties, and toxicities relative to commercially available Ag nanopowder (np-AgNPs) to the clam Mercenaria mercenaria. The chemical synthesis is based on the reduction of ionic silver using sodium borohydride as a reducing agent and trisodium citrate as a capping agent. The biological synthesis is based on the reduction of ionic silver using biomolecules extracted from an atoxigenic strain of a filamentous fungus Aspergillus parasiticus. The properties of AgNPs were determined using UV-vis, dynamic light scattering, laser Doppler electrophoresis, (single particle)-inductively coupled plasma-mass spectroscopy, transmission electron microscopy, and asymmetric flow-field flow fractionation. Both chemical and biological synthesis approaches generated spherical AgNPs. The chemical synthesis produced AgNPs with narrower size distributions than those generated through biological synthesis. The polydispersity of bio-AgNPs decreased with increases in cell free extract (CFE):Ag ratios. The magnitude of the zeta potential of the cit-AgNPs was higher than those of bio-AgNPs. All AgNPs formed aggregates in the test media i.e., natural seawater. Based on the same total Ag concentrations, all AgNPs were less toxic than AgNO₃. The toxicity of AgNPs toward the juvenile clam, Mercenaria mercenaria, decreased following the order np-AgNPs > cit-AgNPs > bio-AgNPs. Expressed as a function of dissolved Ag concentrations, the toxicity of Ag decreased following the order cit-AgNPs > bio-AgNPs > AgNO₃ ~ np-AgNPs. Therefore, the toxicity of AgNP suspensions can be attributed to a combined effect of dissolved and particulate Ag forms. These results indicate that AgNP synthesis methods determine their environmental and biological behaviors and should be considered for a more comprehensive environmental risk assessment of AgNPs.

The Role of Biosynthesized Silver Nanoparticles in Antimicrobial Mechanisms

Nanotechnology is an area of science in which new materials are developed. The correlation between nanotechnology and microbiology is essential for the development of new drugs and vaccines. The main advantage of combining these areas is to associate the latest technology in order to obtain new ways for solving problems related to microorganisms. This review seeks to investigate nanoparticle formation's antimicrobial properties, primarily when connected to the green synthesis of silver nanoparticles. The development of new sustainable methods for nanoparticle production has been instrumental in designing alternative, non-toxic, energy-friendly, and environmentally friendly routes. In this sense, it is necessary to study silver nanoparticles' green synthesis concerning their antimicrobial properties. Antimicrobial silver nanoparticles' mechanisms demonstrate efficiency to gram-positive bacteria, gram-negative bacteria, fungi, viruses, and parasites. However, attention is needed with the emergence of resistance to these antimicrobials. This article seeks to relate the parameters of green silver- based nanosystems with the efficiency of antimicrobial activity.

Biogenic Silver Nanoparticles of Clinacanthus nutans as Antioxidant with Antimicrobial and Cytotoxic Effects

Silver nanoparticles (AgNPs) previously synthesised using leaf (AgNP-L) and stem (AgNP-S) extracts of Clinacanthus nutans (C. nutans) were tested to evaluate antimicrobial, antioxidant, and cytotoxicity activities. The AgNPs showed good inhibition against bacteria, but not fungi. The inhibition results showed the highest activity against Staphylococcus aureus (S. aureus) with 11.35 mm (AgNP-L) and 11.52 mm (AgNP-S), while the lowest inhibition was against Escherichia coli (E. coli) with 9.22 mm (AgNP-L) and 9.25 mm (AgNP-S) in the disc diffusion method. The same trend of results was noted in the well diffusion method. The IC50 of AgNP-L and AgNP-S in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays was 417.05 μg/mL and 434.60 μg/mL, as well as 304.31 μg/mL and 326.83 μg/mL, respectively. Ferric reducing power (FRAP) assay showed that AgNP-L [872.389 μmol/L Fe(II)] and AgNP-S [612.770 μmol/L Fe(II)] exhibited significantly (p < 0.05) greater antioxidant activities than leaf extract (CNL) [152.260 μmol/L Fe(II)] and stem extract (CNS) [110.445 μmol/L Fe(II)] of C. nutans. The AgNPs were also proven to possess cytotoxic effects on the breast (MCF-7), cervical (HeLa), and colon (HT-29) cancer cells in a dose-dependent manner. AgNP-S and AgNP-L showed significantly (p < 0.05) higher cytotoxicity against MCF-7 (117.43 μg/mL) and HT-29 (78.47 μg/mL), respectively. In conclusion, the biosynthesised AgNPs from aqueous extract leaves and stem of C. nutans have demonstrated promising potential towards antioxidant, antimicrobial, and cytotoxicity activities.

Silver Nanoparticles Synthesized Using Carica papaya Leaf Extract (AgNPs-PLE) Causes Cell Cycle Arrest and Apoptosis in Human Prostate (DU145) Cancer Cells

Treatment of cancer has been limited by the poor efficacy and toxicity profiles of available drugs. There is a growing demand to develop alternative approaches to combat cancer such as use of nano-formulation-based drugs. Here, we report biosynthesis and characterization of silver nanoparticles (AgNPs) with papaya leaf extract (PLE) and its anti-cancer properties against different human cancer cells. Purified nanoparticles were characterized by standard techniques, such as TEM, STM, SEM, EDS, XRD, and FTIR. Furthermore, cytotoxic activity of AgNPs-PLE was carried out against different human cancer cells and non-tumorigenic human keratinocytes cells. AgNPs-PLE when compared with AgNPs-citric acid or PLE showed better efficacy against cancer cells and was also relatively less toxic to normal cells. Treatment of DU145 cells with AgNPs-PLE (0.5-5.0 μg/ml) for 24-48 h lowered total cell number by 24-36% (P < 0.05). Inhibition of cell growth was linked with arrest of cell cycle at G2/M phase at 24 h, while G1 and G2/M phase arrests at 48 h. ROS production was observed at earlier time points in presence of AgNPs-PLE, suggesting its role behind apoptosis in DU145 cells. Induction of apoptosis (57%) was revealed by AO/EB staining in DU145 cells along with induction of Bax, cleaved caspase-3, and cleaved PARP proteins. G1-S phase cell cycle check point marker, cyclin D1 was down-regulated along with an increase in cip1/p21 and kip1/p27 tumor suppressor proteins by AgNPs-PLE. These findings suggest the anti-cancer properties of AgNPs-PLE.

A robust electrochemical immunosensor based on core-shell nanostructured silica-coated silver for cancer (carcinoembryonic-antigen-CEA) diagnosis

This work addresses the fabrication of an efficient, novel, and economically viable immunosensing armamentarium that will detect the carcinoembryonic antigen (CEA) typically associated with solid tumors (sarcomas, carcinomas, and lymphomas) and is used as a clinical tumor marker for all these malignancies. We synthesized silver nanoparticles by single-step chemical reduction and coated with silica using a modified Stober method to fabricate silica-coated silver core-shell nanoparticles. The morphologies, structure, and size of the nanoparticles were characterized by Transmission Electron Microscopy (TEM), UV-Visible spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, Fourier Transform Infra-Red Spectroscopy (FTIR), and Dynamic Light Scattering (DLS), respectively. The results indicated that the average size of Ag nanoparticles and silica-coated Ag nanoparticles is 50 nm and 80 nm, respectively. Our TEM results indicate that the silica-shell uniformly encapsulates silver core particles. Further, a disposable electrochemical immunosensor for carcinoembryonic antigen (CEA) was proposed based on the antigen immobilized in a silica-coated silver core-shell nanoparticle film on the surface of an indium-tin-oxide (ITO) flat substrate. The morphological characteristics of the constructed biosensor were observed by scanning electron microscopy (SEM) and electrochemical methods. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were employed for the characterization of the proposed bioelectrode. The cyclic voltammogram appears to be more irreversible on silica coated silver core-shell nanoparticles. It is found that the fabricated immunosensor shows fast potentiometric response under the optimized conditions. The CEA could be determined in the linear range from 0.5 to 10 ng mL-1 with a detection limit of 0.01 ng mL-1 using the interface. The developed flat substrate of ITO for CEA detection (the model reagent) is a potentially promising immunosensing system, manifests good stability, and allows batch fabrication because of its economic feasibility.

Multifunctional and stimuli-responsive nanocarriers for targeted therapeutic delivery

INTRODUCTION

Nanocarrier-based delivery systems offer multiple benefits to overcome limitations of the traditional drug dosage forms, such as protection of the drug, enhanced bioavailability, targeted delivery to disease site, etc. Nanocarriers have exhibited tremendous successes in targeted delivery of therapeutics to the desired tissues and cells with improved bioavailability, high drug loading capacity, enhanced intracellular delivery, and better therapeutic effect. A specific design of stimuli-responsive nanocarriers allows for changing their structural and physicochemical properties in response to exogenous and endogenous stimuli. These nanocarriers show a promise in site specific controlled release of therapeutics under certain physiological conditions or external stimuli.

AREAS COVERED

This review highlights recent progresses on the multifunctional and stimuli-sensitive nanocarriers for targeted therapeutic drug delivery applications.

EXPERT OPINION

The progress from single functional to multifunctional nanocarriers has shown tremendous potential for targeted delivery of therapeutics. On our opinion, the future of targeted delivery of drugs, nucleic acids, and other substances belongs to the site-targeted multifunctional and stimuli-based nanoparticles with controlled release. Targeting of nanocarriers to the disease site enhance the efficacy of the treatment by delivering more therapeutics specifically to the affected cells and substantially limiting adverse side effects upon healthy organs, tissues, and cells.

Eco-friendly and enhanced colorimetric detection of aluminum ions using pectin-rich apple extract-based gold nanoparticles

Aluminum ions are very toxic to human health, especially in relation to neurodegenerative diseases. However, conventional methods of detecting such toxic ions suffer from the use of poisonous chemical probes and complex processes. Herein, we report an eco-friendly and enhanced colorimetric method of aluminum ion detection using green-synthesized gold nanoparticles (AuNPs) from apple (Malus domestica) extract. The apple extract-based AuNPs (AX-AuNPs) contain abundant pectin different from citrate-based AuNPs. The pectin-rich AX-AuNPs improved the sensitivity of the colorimetric detection of aluminum ions. The detection limit was about 20 μM both in artificial and drinking water-based real samples. Interestingly, it is turned out that the AX-AuNPs were aggregated naturally after the chemical assay because of solution getting decayed. For the environmental perspective, it was great that the lump of AX-AuNP aggregates could easily be removed from the solutions before solution discard. Overall, our results indicate that AX-AuNPs offer a high-selectivity, enhanced colorimetric detection of aluminum ions in a short time (less than 1 min), based on an eco-friend synthesis and disposal manner of AuNPs.

Catalytic Degradability of p-Nitrophenol Using Ecofriendly Silver Nanoparticles

In an effort to produce non-toxic and economically viable “green” protocols for waste water treatment, researchers are actively involved to develop versatile and effective silver nanoparticles (SNPs) as nano-catalyst from bio-based techniques. Since, p-nitrophenol (PNP) is one of the anthropogenic contaminants, considerable attention has been focused in catalytic degradability of PNP in wastewater treatment by curtailing serious effect on aquatic fauna. Ingestion of contaminants by aquatic organisms will not only affect the aquatic species but is also a potential threat to human health, especially if the toxic contaminants are involved in food chain. In this short report, we provided a comprehensive insight on few remarkable nanocatalysts especially based on SNPs and its biopolymer composites synthesized via ecofriendly “green” route. The beneficiality and catalytic performance of these silver nanocatalysts are concisely documented on standard model degradation reduction of PNP to p-aminophenol (PAP) in the presence of aqueous sodium borohydride. The catalytic degradation of PNP to PAP using SNPs follows pseudo first order kinetics involving six-electrons with lower activation energy. Furthermore, we provided a list of highly effective, recoverable, and economically viable SNPs, which demonstrated its potential as nanocatalysts by focusing its technical impact in the area of water remediation.

Structural and physicochemical properties of Rheum emodi mediated Mg(OH)2 nanoparticles and their antibacterial and cytotoxic potential

In the present investigation, Rheum emodi roots extract mediated magnesium hydroxide nanoparticles [Mg(OH)2 NPs] through the bio-inspired experimental technique were synthesised. Mg(OH)2 NPs were characterised by using various characterisation techniques such as field emission scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet-visible spectroscopy. The formation of Mg(OH)2 NPs was confirmed by X-ray diffraction. The structural analysis confirmed the hexagonal crystal symmetry of Mg(OH)2 NPs with space group P-3m1 and space group no. 164 using the Rietveld refinement technique. TEM micrographs illustrated the nano-size formation of Mg(OH)2 NPs of spherical shape and size ∼14.86 nm. With the aid of FTIR data, plant metabolites such as anthraquinones have been identified as a stabilising and reducing agent for the synthesis of biogenic Mg(OH)2 NPs. The synthesised Mg(OH)2 NPs showed antimicrobial and cytotoxic potential against Gram-negative and Gram-positive bacteria such as Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) and MDA-MB-231 human breast cancer cell lines.

Cytotoxic Effect of Silver Nanoparticles Synthesized by Green Methods in Cancer

Cancer is a major public health problem, but despite the several treatment approaches available, patients develop resistance in short time periods, making overcoming resistance or finding more efficient treatments an imperative challenge. Silver nanoparticles (AgNPs) have been described as an alternative option due to their physicochemical properties. The scope of this review was to systematize the available scientific information concerning these characteristics in AgNPs synthesized according to green chemistry's recommendations as well as their cytotoxicity in different cancer models. This is the first paper analyzing, correlating, and summarizing AgNPs' main parameters that modulate their cellular effect, including size, shape, capping, and surface plasmon resonance profile, dose range, and exposure time. It highlights the strong dependence of AgNPs' cytotoxic effects on their characteristics and tumor model, making evident the strong need of standardization and full characterization. AgNPs' application in oncology research is a new, open, and promising field and needs additional studies.

Green Synthesis of Silver Nanoparticles Using Artocarpus hirsutus Seed Extract and its Antibacterial Activity

Aims:

To evaluate the antibacterial activity of Artocarpus hirsutus mediated seed extract for nanoparticle synthesis.

Background:

Gastrointestinal bacteria are known for causing deadly infections in humans. They also possess multi-drug resistance and interfere with clinical treatments. Applied nanotechnology has been known to combat such infectious agents with little interference from their special attributes. Here we synthesize silver nanoparticles from Artocarpus hirsutus seed extract against two gastro-intestinal bacterial species: Enterobacter aerogenes and Listeria monocytogenes.

Objective:

To collect, dry, and process seeds of Artocarpus hirsutus for nanoparticle synthesis. To evaluate the morphological interaction of silver nanoparticles with bacteria.

Methods:

Artocarpus hirsutus seeds were collected and processed and further silver nanoparticles were synthesized by the co-precipitation method. The synthesized nanoparticles were characterized using XRD, UV, FTIR, and SEM. These nanoparticles were employed to study the antibacterial activity of nanoparticles against Enterobacter aerogenes and Listeria monocytogenes using well diffusion method. Further, morphological interaction of silver nanoparticles on bacteria was studied using SEM.

Result:

Silver nanoparticles were synthesized using Artocarpus hirsutus seed extract and characterization studies confirmed that silver nanoparticles were spherical in shape with 25-40 nm size. Antibacterial study exhibited better activity against Enterobacter aerogenes with a maximum zone of inhibition than on Listeria monocytogenes. SEM micrographs indicated that Enterobacter aerogenes bacteria were more susceptible to silver nanoparticles due to the absence of cell wall. Also, the size and charge of silver nanoparticles enable easy penetration of the bacterial cell wall.

Conclusion:

In this study, silver nanoparticles were synthesized using the seed extract of Artocarpus hirsutus for the first time exploiting the fact that Moraceae species have high phytonutrient content which aided in nanoparticle synthesis. This nanoparticle can be employed for large scale synthesis which when coupled with the pharmaceutical industry can be used to overcome the problems associated with conventional antibiotics to treat gastrointestinal bacteria.

Optimization of biogenic synthesis of silver nanoparticles from flavonoid-rich Clinacanthus nutans leaf and stem aqueous extracts

Background: Silver nanoparticles (AgNPs) are widely used in food industries, biomedical, dentistry, catalysis, diagnostic biological probes and sensors. The use of plant extract for AgNPs synthesis eliminates the process of maintaining cell culture and the process could be scaled up under a non-aseptic environment. The purpose of this study is to determine the classes of phytochemicals, to biosynthesize and characterize the AgNPs using Clinacanthus nutans leaf and stem extracts. In this study, AgNPs were synthesized from the aqueous extracts of C. nutans leaves and stems through a non-toxic, cost-effective and eco-friendly method. Results: The formation of AgNPs was confirmed by UV-Vis spectroscopy, and the size of AgNP-L (leaf) and AgNP-S (stem) were 114.7 and 129.9 nm, respectively. Transmission electron microscopy (TEM) analysis showed spherical nanoparticles with AgNP-L and AgNP-S ranging from 10 to 300 nm and 10 to 180 nm, with average of 101.18 and 75.38 nm, respectively. The zeta potentials of AgNP-L and AgNP-S were recorded at -42.8 and -43.9 mV. X-ray diffraction analysis matched the face-centred cubic structure of silver and was capped with bioactive compounds. Fourier transform infrared spectrophotometer analysis revealed the presence of few functional groups of phenolic and flavonoid compounds. These functional groups act as reducing agents in AgNPs synthesis. Conclusion: These results showed that the biogenically synthesized nanoparticles reduced silver ions to silver nanoparticles in aqueous condition and the AgNPs formed were stable and less toxic.

Green synthesis of silver nanoparticles using methanolic fruit extract of Aegle marmelos and their antimicrobial potential against human bacterial pathogens

Plant-based synthesis of nanoparticles has generated worldwide interest because of cost-effectiveness, eco-friendly nature and plethora of applications. In the present investigation, antimicrobial potential of silver nanoparticles (AgNPs) of methanolic extract of Aegle marmelos fruit has been investigated. Agar well diffusion method was used for determining antimicrobial activity of solvent extracts (viz., petroleum ether, chloroform, acetone, methanol and aqueous), and AgNPs. Among these, methanolic extract of A. marmelos showed highest inhibitory activity against B. cereus (16.17 ± 0.50 mm) followed by P. aeruginosa (13.33 ± 0.62 mm) and E. coli. Phytochemical analysis of methanolic extract of A. marmelos revealed the presence of tannins, saponins, steroids, alkaloids, flavonoids, and glycosides. AgNPs synthesized using A. marmelos methanolic extract, characterized by UV-Visible spectroscopy, atomic force microscopy, dynamic light scattering, and X-ray diffraction showed a peak at 436 nm and size ranged between 159 and 181 nm. Evaluation of the antimicrobial potential of green synthesized AgNPs recorded the highest inhibitory activity against B. cereus (19.25 ± 0.19 mm) followed by P. aeruginosa (16.50 ± 0.30 mm) and S. dysentriae. The minimum inhibitory concentration (MIC) of synthesized AgNPs was found to be in the range of 0.009875-0.0395 mg/100 μl which was quite lower than the MIC of crude extract i.e. 0.0781-0.3125 mg/100 μl. The results obtained indicated that the different crude extracts of A. marmelos plant as well as AgNPs have a strong and effective antimicrobial potential that provide a marvelous source for the development of new drug molecules of herbal origin which may be used for the welfare of humanity.

Biosynthesis of hematite nanoparticles using Rheum emodi and their antimicrobial and anticancerous effects in vitro

The synthesis of magnetic Hematite nanoparticles (α-Fe2O3) via green route has been a long lasting challenge for the scientific and technological fascination of many researchers. In the present investigation, iron oxide nanoparticles (α-Fe2O3) were synthesized using Rheum emodi roots in a cost effective and ecofriendly method. Their physicochemical property orchestration involved techniques such as UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray (EDX), X-ray diffraction (XRD), Thermogravimetric Analysis (TGA), Vibrating sample magnetometer (VSM), and Atomic force microscopy (AFM). Through TEM, FESEM and AFM analysis, α-Fe2O3NPs were confirmed spherical in shape and the average diameter of particle is ~12 nm as depicted through TEM image. Thermal property was investigated by TGA. Magnetic behavior was observed in R. emodi mediated α-Fe2O3NPs by magnetic hysteresis measurements. FTIR analysis revealed the presence of anthraquinones in R. emodi roots extract which play the central role in stabilization of the α-Fe2O3NPs. Further, the crystalline nature of the nanoparticle sample was determined with XRD experiment and SAED fringes calculation. The crystal was also confirmed with Rietveld refinement of XRD profile fitted with R-3c model Additionally, magnetic interaction with bacterial cell wall showed antimicrobial property against Escherichia coli, Gram-negative and Staphylococcus aureus, Gram-positive species. The approach transcribed in this paper reveals a novel methodology that utilizes α-Fe2O3 NPs to initiate apoptosis and inhibition of cervical cancer cells.

Biogenic synthesis of silver nanoparticles: Antibacterial and cytotoxic potential

In green chemistry, the application of a biogenic material as a mediator in nanoparticles formation is an innovative nanotechnology. Our current investigation aimed at testing the cytotoxic potential and antimicrobial ability of silver nanoparticles (AgNPs) that were prepared using Calligonum comosum roots and Azadirachta indica leaf extracts as stabilizing and reducing agents. An agar well diffusion technique was employed to detect synthesized AgNPs antibacterial ability on Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus bacterial strains. Furthermore, their cytotoxic capability against LoVo, MDA-MB231 and HepG2 ca cells was investigated. For phyto-chemical detection in the biogenic AgNPs the Fourier-transform infrared spectroscopy (FT-IR) was considered. Zeta sizer, TEM (Transmission Electron Microscope) and FE-SEM (Field Emission Scanning Electron Microscope) were used to detect biogenic AgNPs' size and morphology. The current results showed the capability of tested plant extract for conversion of Ag ions to AgNPs with a mean size ranging between 90.8 ± 0.8 and 183.2 ± 0.7 nm in diameter. Furthermore, prepared AgNPs exhibited apoptotic potential against HepG2, LoVo, and MDA-MB 231cell with IC₅₀ ranging between 10.9 and 21.4 μg/ml and antibacterial ability in the range of 16.0 ± 0.1 to 22.0 ± 1.8 mm diameter. Activation of caspases in AgNPs treated cells could be the main indicator for their positive effect causing apoptosis. The current investigation suggested that the green production of AgNPs could be a suitable substitute to large-scale production of AgNPs, since stable and active nanoparticles could be obtained.

Biosynthesis and Characterization of Silver Nanoparticles Using Phoenix dactylifera Fruits Extract and their In Vitro Antimicrobial and Cytotoxic Effects

Background:

In this article, silver nanoparticles (AgNPs) were synthesized by the biological green technique, using the aqueous extracts obtained from fruits of Phoenix dactylifera (date palm). This method is simple, rapid, non-toxic, and sustainable, and substitutes for the conventional physical/chemical methods. The cytotoxic activities of AgNPs derived from date fruit extract have not been mentioned in the earlier studies.

Methods:

The biosynthesized AgNPs are analyzed by Fourier transform infrared spectroscopy (FT-IR), UV-visible spectroscopy (UV-vis), and Transmission Electron Microscopy (TEM) methods. The assessment of antimicrobial effect towards human pathogenic microbial strains and their potential cytotoxicity against human breast cancer cell lines (MCF-7) were also evaluated.

Results:

FT-IR spectral studies showed that phytomolecules such as carbohydrates, phenolic acids and flavonoids present in date fruits extract are involved in the reduction and capping of the AgNPs. UV-vis spectrum revealed Surface Plasmon Resonance (SPR) at 425 nm which attributes the presence of AgNPs in aqueous extract. TEM micrographs showed that AgNPs particle diameter is ranged from 20 nm to 100 nm with spherical morphology. The biosynthesized AgNPs exhibited significant antimicrobial activity towards human microbial strains. Phytosynthesized NPs also induce cytotoxicity via necrosis, apoptosis and mitodepressive mechanisms that can disturb the cellular components at various stages of cell cycle.

Conclusion:

The present study concludes that biologically synthesized AgNPs using Phoenix dactylifera is cost-effective, rapid, non-toxic, and sustainable and can be effectively used as an adjunct for the treatment of breast carcinoma.

Multifunctional mesoporous curcumin encapsulated iron-phenanthroline nanocluster: A new Anti-HIV agent

A new strategy to encapsulating the drug curcumin into the hydrophobic core of the iron-phenanthroline nanocomplex (NIP) and eventually its release is signified. NIP was prepared via coordinate interaction between Fe²⁺ and the lone pairs present on the N atoms of the bidentate phenanthroline ligand (spherical morphology, diameter 18.8 nm, mesoporous with pore size 2.443 nm, amorphous). Thereafter, curcumin was successfully encapsulated (NCIP) in NIP, resulting in its enhanced stability (spherical morphology, diameter 46.8 nm). The nanocomplex NIP was used for drug delivery applications. We evaluated the anti-HIV effects of NCIP in vitro on cultures of HIV infected human microglia. The treatment of HIV-1 infected microglia with NCIP significantly decreased the expression of HIV-p24 by 41% and pro-inflammatory mediators TNF-α, IL-8 and NO by 61.2%, 41% and 50.2%, respectively, compared to NIP. Flow cytometry data also support the decrease in TNF-α and IL-8 expression in case of NCIP. NCIP induced antioxidative effects by increasing the gene expression of catalase (CAT) and simulatenously decreasing hemeoxygenase-1 (HMOX-1) gene expression, thereby maintaining homeostasis which reduces neuroinflammation. These results support our premise that NCIP may be a significant adjuvant when used with traditional anti-retroviral regimens and may ameliorate HIV-1 associated neurotoxicity.

Morphology control of colloidal silver bio-nanoparticles leaves shape using Sesbania sesban

Sesbania sesban extract solution (SSL) was used as a reducing and stabilizing agent for the synthesis of colloidal silver nanoparticles (AgNPs). The effect of time on the formation of nanoparticles was investigated using ultraviolet–visible spectroscopy. The AgNPs were synthesized after 25 min and characterized by high-resolution transmission electron microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The average sizes of nanoparticles were estimated to be between 10 and 30 nm. The XRD of AgNPs, after 4 months, showed the stability of nanoparticles in air. The effects of silver nitrate concentrations and SSL concentrations on the morphology and size of synthesized AgNPs were observed by SEM.

Characterization and cytotoxic effect of biogenic silver nanoparticles on mitotic chromosomes of Drimia polyantha (Blatt. & McCann) Stearn

Noble metal nanoparticles afford a tool for investigation and its application in biological systems has had the greatest impact in biology and biomedicine. The present work reports an ecofriendly approach for the synthesis of silver nanoparticles (AgNPs) using an aqueous leaf extract of Getonia floribunda. The silver nanoparticles were characterized by using following instruments viz. UV-vis spectrophotometer, FTIR, XRD AFM and HR-TEM. The UV-vis spectrum showed a characteristic absorption peak at 404 nm. FTIR data reveals the possible involvement of various functional groups for reduction and biocapping of AgNPs. XRD data confirmed the crystalline nature of silver nanoparticles. Morphology, size and distribution of the AgNPs were determined by using AFM and HR-TEM. The average size of AgNPs ranges between 10 and 25 nm and are spherical in shape. The silver nanoparticles were evaluated for their cytotoxic effect on mitotic chromosomes of root meristematic cells of D. polyantha using different concentrations viz. 4, 8, 12 and 16 μg/ml at the time interval of 6, 12, 18 and 24 h. It is evident from the results that the higher concentration of AgNPs found to inhibit mitotic index and caused chromosomal abnormalities such as chromosomal bridge, sticky chromosomes, laggard anaphase, diagonal anaphase, c-metaphase and chromosomal breaks. Therefore, it can be concluded that higher concentrations of silver nanoparticles may induce significant inhibition of root meristem activity and causing DNA damage.

Phytofunctionalized silver nanoparticles: green biomaterial for biomedical and environmental applications

Variegated physicochemical routes with emerging modifications have been adopted and reported for silver nanoparticle synthesis for centuries. Nano-biotechnology aimed at the synthesis of nanomaterials, including silver nanoparticles, through utilization of biological media has acquired an auspicious role in science for human welfare. Despite recurrent nanoscale researches on physicochemical routes, coeval stages are predominated by greener methods in silver nanoparticle synthesis for the utilization of its inherent toxicity and exceedingly smaller sizes for biological and environmental applications. One of the principles of green routes for silver nanoparticle synthesis is reduction and stabilization via phytochemicals extracted from plants in a one-pot protocol of phytofunctionalization. Plants are preferred for their abundant availability, environmental non-toxicity and economical favorability and chiefly for the ease of aptness, unlike microbial pathways having tedious requirements of cellular culture maintenance conditions. The present work reviewed the most recent milestones set in the selection of types and parts of plants and optimized synthetic conditions employed in the fabrication of silver nanoparticles, in addition to quantitative and qualitative characterization. Furthermore, the use of phytofunctionalized silver nanoparticles for microbial growth inhibition and environmental remediation was also studied. Through the meticulous review of literature, potential applications were highlighted, which can provide researchers with a plethora of avenues for future investigations for remediation of the environment, in terms of both combating pathogenic microbes and environmental detoxification.