Biomimetic synthesis and anticancer activity of Eurycoma longifolia branch extract‐mediated silver nanoparticles

In the present study, silver nanoparticles (AgNPs) were synthesised by adding 1 mM Ag nitrate solution to different concentrations (1%, 2.5%, 5%) of branch extracts of Eurycoma longifolia, a well known medicinal plant in South–East Asian countries. Characterisation of AgNPs was carried out using techniques such as ultraviolet–visible spectrophotometry, X‐ray diffractrometry, Fourier transform infrared–attenuated total reflection spectroscopy (FTIR–ATR), scanning electron microscopy. XRD analysis revealed face centre cubic structure of AgNPs and FTIR–ATR showed that primary and secondary amide groups in combination with the protein molecules present in the branch extract were responsible for the reduction and stabilisation of AgNPs. Furthermore, antioxidant [2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐Azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid)], antimicrobial and anticancer activities of AgNPs were investigated. The highest bactericidal activity of these biogenic AgNPs was found against Escherichia coli with zone inhibition of 11 mm. AgNPs exhibited significant anticancer activity against human glioma cells (DBTRG and U87) and human breast adenocarcinoma cells (MCF‐7 and MDA‐MB‐231) with IC₅₀ values of 33, 42, 60 and 38 µg/ml.Inspec keywords: biomimetics, cancer, antibacterial activity, nanoparticles, silver, microorganisms, cellular biophysics, biomedical materials, nanomedicine, nanofabrication, X‐ray diffraction, Fourier transform infrared spectra, attenuated total reflection, ultraviolet spectra, visible spectra, proteins, molecular biophysics, biochemistryOther keywords: Biomimetic synthesis, anticancer activity, Eurycoma longifolia branch extract‐mediated silver nanoparticles, nitrate solution, medicinal plant, ultraviolet‐visible spectrophotometry, X‐ray diffractometry, Fourier transform infrared‐attenuated total reflection spectroscopy, FTIR‐ATR spectroscopy, scanning electron microscopy, XRD, face centre cubic structure, primary amide groups, secondary amide groups, protein molecules, antioxidant, 2,2‐diphenyl‐1‐picrylhydrazyl, 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid), antimicrobial activity, bactericidal activity, biogenic silver nanoparticles, Escherichia coli, zone inhibition, DBTRG human glioma cells, U87 human glioma cells, MCF‐7 human breast adenocarcinoma cells, MDA‐MB‐231 human breast adenocarcinoma cells, Ag     

Eco-friendly green synthesis of silver nanoparticles and their potential applications as antioxidant and anticancer agents

Abstract

Eco-friendly green synthesis of nanoparticles using medicinal plants gained immense importance due to its potential therapeutic uses. In the current study, silver nanoparticles (AgNPs) were synthesized using water extract of Jurinea dolomiaea leaf and root at room temperature. MTT assay was used to study anticancer potential of AgNPs against cervical cancer cell line (HeLa), breast cancer cell lines (MCF-7), and mouse embryonic fibroblast (NIH-3 T3) cell line for toxicity evaluation. The antioxidant potential was evaluated using stable DPPH radicals. In addition, the apoptotic nuclear changes prompted by AgNPs in more susceptible HeLa cells were observed using fluorescence microscope through DAPI and PI staining. Physiochemical properties of biosynthesized AgNPs were characterized using various techniques. AgNPs were formed in very short time and UV–vis spectra showed characteristic absorption peak of AgNPs. SEM and TEM showed spherical shape of AgNPs and XRD revealed their crystalline nature. EDX analysis revealed high percentage of silver in green synthesized AgNPs. FTIR analysis indicated involvement of secondary metabolites in fabrication of AgNPs. In vitro cytotoxic and antioxidant study revealed that herb and biosynthesized AgNPs exhibited significant dose-dependent and time-dependent anticancer and antioxidant potential. Furthermore, study on normal cell line and microscopic analysis of apoptosis revealed that AgNPs exhibited good safety profile as compared to cisplatin and induces significant apoptosis effect. Based on the current findings, it is strongly believe that use of J. dolomiaea offers large scale production of biocompatible AgNPs that can be used as alternative anticancer agents against cancer cell lines tested.     

Biomimetic synthesis and patterning of silver nanoparticles

The creation of nanoscale materials for advanced structures has led to a growing interest in the area of biomineralization. Numerous microorganisms are capable of synthesizing inorganic-based structures. For example, diatoms use amorphous silica as a structural material, bacteria synthesize magnetite (Fe3O4) particles and form silver nanoparticles, and yeast cells synthesize cadmium sulphide nanoparticles. The process of biomineralization and assembly of nanostructured inorganic components into hierarchical structures has led to the development of a variety of approaches that mimic the recognition and nucleation capabilities found in biomolecules for inorganic material synthesis. In this report, we describe the in vitro biosynthesis of silver nanoparticles using silver-binding peptides identified from a combinatorial phage display peptide library.     

Actinobacterial‐mediated synthesis of silver nanoparticles and their activity against pathogenic bacteria

In this study, silver nanoparticles (AgNPs) were biosynthesised by using acidophilic actinobacterial SH11 strain isolated from pine forest soil. Isolate SH11 was identified based on 16S rRNA gene sequence to Streptomyces kasugaensis M338‐M1^T and S. celluloflavus NRRL B‐2493^T (99.8% similarity, both). Biosynthesised AgNPs were analysed by UV–visible spectroscopy, which revealed specific peak at λ  = 420 nm. Transmission electron microscopy analyses showed polydispersed, spherical nanoparticles with a mean size of 13.2 nm, while Fourier transform infrared spectroscopy confirmed the presence of proteins as the capping agents over the surface of AgNPs. The zeta potential was found to be −16.6 mV, which indicated stability of AgNPs. The antibacterial activity of AgNPs from SH11 strain against gram‐positive (Staphylococcus aureus and Bacillus subtilis) and gram‐negative (Escherichia coli) bacteria was estimated using disc diffusion, minimum inhibitory concentration and live/dead analyses. The AgNPs showed the maximum antimicrobial activity against E. coli, followed by B. subtilis and S. aureus. Further, the synergistic effect of AgNPs in combination with commercial antibiotics (kanamycin, ampicillin, tetracycline) was also evaluated against bacterial isolates. The antimicrobial efficacy of antibiotics was found to be enhanced in the presence of AgNPs.Inspec keywords: antibacterial activity, silver, nanoparticles, electrokinetic effects, Fourier transform infrared spectra, microorganisms, nanofabricationOther keywords: actinobacterial mediated synthesis, silver nanoparticles, pathogenic bacteria, biosynthesis, acidophilic actinobacterial SH11 strain, pine forest soil, 16S rRNA gene sequence, Streptomyces kasugaensis M338‐M1T, S. celluloflavus NRRL B‐2493T, UV–visible spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, gram positive bacteria, Staphylococcus aureus, Bacillus subtilis, gram negative bacteria, Escherichia coli, disc diffusion, wavelength 420 nm, Ag     

Green synthesis of silver nanoparticles using Mentha pulegium and investigation of their antibacterial,antifungal and anticancer activity

A simple and eco‐friendly method for efficient synthesis of stable colloidal silver nanoparticles (AgNPs) using Mentha pulegium extracts is described. A series of reactions was conducted using different types and concentrations of plant extract as well as metal ions to optimize the reaction conditions. AgNPs were characterized by using UV–vis spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering, zetasizer, energy‐dispersive X‐ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). At the optimized conditions, plate shaped AgNPs with zeta potential value of ‐15.7 and plasmon absorption maximum at 450 nm were obtained using high concentration of aqueous extract. Efficient adsorption of organic compounds on the nanoparticles was confirmed by FTIR and EDAX. The biogenic AgNPs displayed promising antibacterial activity on Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes. The highest antibacterial activity of 25 µg mL‐1 was obtained for all the strains using aqueous extract synthesized AgNPs. The aqueous extract synthesised AgNPs also showed considerable antifungal activity against fluconazole resistant Candida albicans. The cytotoxicity assay revealed considerable anticancer activity of AgNPs on HeLa and MCF‐7 cancer cells. Overall results indicated high potential of M. pulegium extract to synthesis high quality AgNPs for biomedical applications.Inspec keywords: silver, nanoparticles, nanofabrication, botany, antibacterial activity, biomedical materials, nanomedicine, ultraviolet spectra, visible spectra, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, electrokinetic effects, microorganisms, cellular biophysics, cancerOther keywords: antibacterial activity, antifungal activity, anticancer activity, stable colloidal silver nanoparticle, Mentha pulegium, plant extract, UV‐visible spectroscopy, transmission electron microscopy, atomic force microscopy, DLS, zetasizer, energy‐dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, methanolic extract, aqueous extract, plate‐shaped silver nanoparticle, zeta potential, plasmon absorption maximum, organic compounds adsorption, biogenic silver nanoparticle, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, fluconazole‐resistant Candida albicans, MTT assay, HeLa cancer cell, MCF‐7 cancer cell, Ag     

Chrysin-loaded folate conjugated PF127-F68 mixed micelles with enhanced oral bioavailability and anticancer activity against human breast cancer cells

Chrysin (CH), a phytoconstituent has numerous pharmacological activities including anticancer activity. However, CH suffers from a drawback of poor aqueous solubility and in turn poor bioavailability limiting its clinical utility. In this work CH loaded folate-conjugated pluronic PF127-pluronic F68 mixed micelles were prepared with an objective to augment oral bioavailability and cytotoxicity of CH in human breast cancer cell line MCF-7 by active targeting mechanism. Folate-conjugated PF127 was synthesized and used for preparation of CH-MM. Optimized batch (using factorial design) of CH-MM was characterized by Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM), in vitro CH release, in vivo study, and in vitro cell line study. FTIR study suggested encapsulation of CH into the micelle core. CH-MM showed controlled release of CH releasing higher amount (2.5 fold) in 24?h when compared to CH alone (A-CH). Further significant increase in C_max (2 fold) and AUC_0–∞ (3 fold) for CH-MM when compared to A-CH suggested significant improvement in oral bioavailability of CH. Additionally, CH-MM showed 5 fold reduction in GI₅₀ value of CH when tested in MCF-7 cells reducing GI₅₀ value of CH significantly. CH-MM can serve as a platform carrier system for active targeting of BCS class II molecules with potential anticancer activity.     

Bio-mechanochemical synthesis of silver nanoparticles with antibacterial activity

By using a bio-mechanochemical approach combining mechanochemistry (ball milling) and green synthesis for the first time, silver nanoparticles (Ag NPs) with antibacterial activity were successfully synthesized. Concretely, eggshell membrane (ESM) or Origanum vulgare L. plant (ORE) and silver nitrate were used as environmentally friendly reducing agent and Ag precursor, respectively. The whole synthesis took 30?min in the former and 45?min in the latter case. The photon cross-correlation measurements have shown finer character of the product in the case of milling with Origanum. UV–Vis measurements have shown the formation of spherical NPs in both samples. TEM study has revealed that both samples are composites of nanosized silver nanoparticles homogenously dispersed within the organic matrices. It has shown that the size and size distribution of the silver nanoparticles is smaller and more uniform in the case of eggshell membrane matrix implying lower silver mobility within this matrix. The antibacterial activity was higher for the silver nanoparticles synthesized with co-milling with Origanum plant than in the case of milling with eggshell membrane.     

Green synthesis of silver nanoparticles and biopolymer nanocomposites: a comparative study on physico-chemical,antimicrobial and anticancer activity

The current report was intended towards comparative study of green-synthesized biogenic Rhubarb silver nanoparticles (RS-AgNPs) and chitosan crosslinked silver nanocomposites (CSHD-AgNCs). The physico-chemical characterization was done by UV–visible, FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDX, TGA, XRD and zeta potential (\(\zeta \)). The analysis and spectroscopic characterization was done by SEM and TEM and their results reveal that the nanoparticles are spherical in shape, with average size ranges from 5 to 50 nm, and was gathered by face centered cubic (FCC) structure throughout the polymer matrix and stable without any protecting or capping reagents over 450 days. The antimicrobial property of RS-AgNPs and CSHD-AgNCs (\(\zeta = +29.6\) and \(+\)32.8 mV) was evaluated against E. coli and S. aureus and showed an effective inhibitory property. The RS-AgNPs and CSHD-AgNCs were assessed for their anticancer activity against HeLa cell line by MTT method, and it reveals a dose–response activity, time and cell line-dependent cytotoxicity. Based on the results obtained, the RS-AgNPs exhibited higher toxicity over CSHD-AgNCs after 24 h incubation of HeLa cells with different concentrations and is negligible for the aqueous Rhubarb extract. It was concluded that the changes in anticancer activity towards HeLa cells due to biological activity of silver nanoparticles depend on their method of biosynthesis and their physico-chemical nature.     

PAMAM-modified citric acid-coated magnetic nanoparticles as pH sensitive biocompatible carrier against human breast cancer cells

Denderimer-modified magnetic nanoparticles are a promising drug delivery nanosystem which can improve the therapeutic efficacy of chemotherapy drugs and can also be beneficial as magnetic resonance (MR) images contrast agent. The present study introduces the preparation and characterization of the potential therapeutic efficiency of curcumin (CUR)-loaded denderimer-modified citric acid coated Fe₃O₄ NPs. Polyamidoamine (PAMAM, generation G₅) was used to encapsulate citric acid coated Fe₃O₄ nanoparticles. The successful preparation of CUR-loaded nanocarriers were confirmed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM) techniques. The loading capacity and encapsulation efficiency of CUR molecules were 12?±?0.03% and 45.58?±?0.41%, respectively. The anticancer effect of void CUR and CUR-loaded nanocarriers were compared to each other by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay on treated MCF-7 cell line. It can be concluded that application of nanoparticles can be more effective strategy for controlled and slow release of CUR in human breast cancer treatment.     

Bio‐inspired synthesis of silver nanoparticles from leaf extracts of Cleistanthus collinus (Roxb.): its potential antibacterial and anticancer activities

In this investigation, the biological synthesis method was adopted to synthesise silver nanoparticles (AgNPs) by using the leaf extracts of Cleistanthus collinus (C. collinus). This plant has traditionally been used to remove the harmful pest from the agriculture field. Leaf extract of C. collinus was used as bioreductant on the precursor solvent of AgNO₃. The synthesised AgNPs were characterised by spectroscopic method such as UV–vis spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, dynamic light scattering and microscopic method by field‐emission scanning electron microscopy analysis. The AgNPs were studied for both antibacterial and antifungal activities and found to exhibit potential antibacterial activity against Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa. The anticancer activity of AgNPs was screened against A‐431 osteosarcoma cell line by [3‐(4, 5‐dimetheylthiazol‐2)‐2, 5 diphenyl tetrazolium bromide] assay and the IC₅₀ value was found to be 91.05 ± 1.53 μg/ml. This trend of eco‐friendly stable synthesis of AgNPs could prove a better substitute for the chemical methods and offer greater opportunity to use these nanosilvers in agricultural and biomedical sectors.Inspec keywords: bio‐inspired materials, silver, nanoparticles, nanomedicine, antibacterial activity, cancer, biomedical materials, microorganisms, nanofabrication, attenuated total reflection, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, light scattering, scanning electron microscopy, field emission electron microscopy, cellular biophysicsOther keywords: bio‐inspired synthesis, silver nanoparticles, Cleistanthus collinus, antibacterial activity, anticancer activity, leaf extracts, biological synthesis method, bioreductant, precursor solvent, UV‐visible spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, dynamic light scattering, field‐emission scanning electron microscopy, Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, A‐431 osteosarcoma cell line, 3‐(4, 5‐dimetheylthiazol‐2)‐2,5 diphenyl tetrazolium bromide assay, eco‐friendly stable synthesis, Ag     

Ipomea carnea-based silver nanoparticle synthesis for antibacterial activity against selected human pathogens

The biosynthesis of silver nanoparticles (AgNps) has a wide range of applications, and here we develop a rapid synthesis using the leaf extract of Ipomea carnea. We demonstrated that 100?mL of a 1?mM silver nitrate solution was reduced to AgNps by 500?µL of I. carnea extract in 5?min and that one or more of the chemical constituents present in the extract acted as the reducing agent. Surface plasmon resonance peaks were observed from 410 to 440?nm for AgNps synthesised using the plant extract, and the peaks showed a characteristic blue shift with variation of pH from 2 to 8. Particle size analysis revealed the size of the AgNps to be from 30 to 130?nm, which was also confirmed by dynamic light scattering, atomic force microscopy and transmission electron microscopy. Additionally, the antibacterial effects of the AgNps were evaluated against selected human pathogens such as Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Klebsiella pneumoniae, Aeromonas hydrophila, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa. Finally, the AgNps were impregnated with a cellulose acetate membrane to form an antimycobacterial membrane. Antimycobacterial activity against a non-pathogenic Mycobacterium smegmatis showed that the AgNp-embedded membrane system has a zone of inhibition of 14?mm.     

Augmented anticancer activity of naringenin-loaded TPGS polymeric nanosuspension for drug resistive MCF-7 human breast cancer cells

Naringenin (NAR) is a naturally occurring plant flavonoid, found predominantly in citrus fruits, possesses a wide range of pharmacological properties. However, despite the therapeutic potential of NAR, its clinical development has been hindered due to low aqueous solubility and inefficient transport across biological membranes resulting in low bioavailability at tumor sites. In our previous studies, nanosuspension of naringenin (NARNS) was prepared using high pressure homogenization method using different polymers. D-α-Tocopheryl polyethylene glycol succinate 1000 (TPGS) was added as a co-stabilizer. All formulation characterization studies were performed. As a continuation of our previous research, current study has further evaluated the ability of the TPGS-coated NARNS, to reverse drug-resistance of P-gp-over expressing MCF-7 human breast adenocarcinoma cell line and animal model. MTT-based colorimetric assay revealed higher cytotoxic efficacy of NARNS than free NAR in MCF-7 cells. NARNS treatment significantly increased intracellular ROS level, mitochondrial membrane potential, caspase-3 activity, lipid peroxidation status (TBARS) and decreased GSH levels when compared to free NAR treatment in MCF-7 cells. It has been also noticed that the presence of apoptotic indices (membrane blebbing, nuclear fragmentation) in NARNS treated cancer cells. Further, NARNS exhibited dose-dependent in vitro antitumor activity with DLA cells. A significant increase in the life span and a decrease in the cancer cell number and tumor weight were noted in the tumor-induced mice after treatment with NARNS.     

Doxorubicin-CdS nanoparticles: a potential anticancer agent for enhancing the drug uptake of cancer cells

A novel strategy of enhancing the drug uptake by cancer cells through the combination of anticancer drug doxorubicin with cadium sulfide (CdS) nanoparticles has been explored by using confocal fluorescence scanning microscopy as well as electrochemical studies, which demonstrates that CdS nanoparticles can readily conjugate with doxorubicin on the targeted cancer cells and facilitate the uptake of drug molecules in the human leukemia K562 cells. Besides, our observations also indicate that the aggregation of the leukemia cells occured when CdS nanoparticles were introduced into the relative target system together with doxorubicin, suggesting that the specific association of CdS nanoparticles with biologically active molecules on the surface of leukemia K562 cells may change some biorecognition or signal transfer pathway among cancer cells. It is suggested that the competitive binding of CdS nanoparticles with accompanying anticancer drug to the membrane of leukemia K562 cells could efficiently prevent the drug release by the drug resistant leukemia cells and thus inhibit the relative multidrug resistance (MDR) of targeted cancer cells.     

Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity

High‐quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20–40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, colloids, particle size, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, microorganisms, nanomedicine, biomedical materialsOther keywords: Green synthesis, flower extract, Malva sylvestris, antibacterial activity, high‐quality colloidal silver nanoparticles, hydroalcoholic extracts, plant extract, reducing agents, stabilising agents, transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, UV– vis spectroscopy, colloidal solutions, particle size distribution, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, disk diffusion, minimum inhibitory concentrations, minimum bactericidal concentrations assays, ethanolic extract, size 430 nm, size 485 nm, size 504 nm, size 20 nm to 40 nm, Ag     

Synthesis of gold and silver nanoparticles using Mukia maderaspatna plant extract and its anticancer activity

The present investigation reveals the in vitro cytotoxic effect of the biosynthesised metal nanoparticles on the MCF 7 breast cancer cell lines. The gold and silver nanoparticles were synthesised through an environmentally admissible route using the Mukia Maderaspatna plant extract. Initially, the biomolecules present in the plant extract were analysed using phytochemical analysis. Further, these biomolecules reduce the metal ion solution resulting from the formation of metal nanoparticles. The reaction parameters were optimised to control the size of nanoparticles which were confirmed by UV visible spectroscopy. Various instrumental techniques such as Fourier transform‐infrared spectroscopy, high resolution transmission electron microscopy, energy dispersive X‐ray and scanning electron microscopy were employed to characterise the synthesised gold and silver nanoparticles. The synthesised gold and silver nanoparticles were found to be 20–50 nm and were of different shapes including spherical, triangle and hexagonal. MTT and dual staining assays were carried out with different concentrations (1, 10, 25, 50 and 100 µg/ml) of gold and silver nanoparticles. The results show that the nanoparticles exhibited significant cytotoxic effects with IC 50 value of 44.8 µg/g for gold nanoparticles and 51.3 µg/g for silver nanoparticles. The observations in this study show that this can be developed as a promising nanomaterial in pharmaceutical and healthcare sector.Inspec keywords: gold, silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, cancer, cellular biophysics, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, scanning electron microscopyOther keywords: gold nanoparticle synthesis, silver nanoparticle synthesis, Mukia maderaspatna plant extract, anticancer activity, MCF 7 breast cancer cell line, biomolecule, phytochemical analysis, size 20 nm to 50 nm, healt hcare sector, pharmaceutical sector, nanomaterial, dual staining assay, MTT assay, scanning electron microscopy, energy dispersive X‐ray spectrocopy, high resolution transmission electron microscopy, Fourier transform‐infrared spectroscopy, instrumental technique, ultraviolet‐visible spectroscopy, metal nanoparticle formation, metal ion solution     

Bio-synthesis of gold and silver nanoparticles from Candida guilliermondii and their antimicrobial effect against pathogenic bacteria

In the present study we investigated the extra cellular synthesis of gold and silver nanoparticles by using the yeast Candida guilliermondii. The formation of noble metal nanoparticles was monitored by the UV-Visible spectroscopy. As prepared gold and silver nanoparticles showed distinct surface plasmon peaks at 530 nm and 425 nm respectively. Phase and morphology of the as synthesized materials were investigated by X-ray diffraction and electron microscopy techniques respectively. XRD patterns confirmed the formation of gold and silver nanoparticles with face centered cubic structures. Bio-TEM images showed the formation of near spherical, well dispersed gold and silver nanoparticles in the size range of 50-70 nm and 10-20 nm respectively. The biosynthesized nanoparticles were tested for their antimicrobial activity against five pathogenic bacterial strains. The highest efficiency for both gold and silver nanoparticles was observed against Staphylococcus aureus. A comparative study was also done to find the effect of chemically synthesized noble metal nanoparticles against the above test strains. Chemically synthesized particles had no antimicrobial activity against any of the pathogenic strains. The results obtained suggest that biosynthesized gold and silver nanoparticles can be used as effective antimicrobial agents against some of the potential harmful pathogenic microorganisms.     

Cytotoxic potentials of biologically fabricated platinum nanoparticles from Streptomyces sp. on MCF‐7 breast cancer cells

Biosynthesis of novel therapeutic nano‐scale materials for biomedical and pharmaceutical applications has been enormously developed, since last decade. Herein, the authors report an ecological way of synthesising the platinum nanoparticles (PtNPs) using Streptomyces sp. for the first time. The produced PtNPs exhibited the face centred cubic system. The fourier transform infrared spectrum revealed the existence of amino acids in proteins which serves as an essential reductant for the formation of PtNPs. The spherical morphology of the PtNPs with an average size of 20–50 nm was observed from topographical images of atomic force microscopy and field emission scanning electron microscopy. The X‐ray fluorescence spectrum confirms the presence of PtNPs with higher purity. The PtNPs size was further confirmed with transmission electron microscopy analysis and the particles were found to exist in the same size regime. Additionally, PtNPs showed the characteristic surface plasmon resonance peak at 262 nm. Dynamic light scattering studies report that 97.2% of particles were <100 nm, with an average particle diameter of about 45 nm. Furthermore, 3‐(4, 5‐dimethyl‐2‐thiazolyl)‐2, 5‐diphenyl‐tetrazolium assay based in vitro cytotoxicity analysis was conducted for the PtNPs, which showed the inhibitory concentration (IC₅₀) at 31.2 µg/ml against Michigan Cancer Foundation‐7 breast cancer cells.Inspec keywords: biomedical materials, materials preparation, nanoparticles, nanomedicine, nanofabrication, cellular biophysics, microorganisms, cancer, platinum, Fourier transform infrared spectra, proteins, atomic force microscopy, scanning electron microscopy, fluorescence, transmission electron microscopy, surface plasmon resonance, light scatteringOther keywords: cytotoxic potentials, biologically fabricated platinum nanoparticles, Streptomyces sp, MCF‐7 breast cancer cells, biosynthesis, therapeutic nanoscale materials, biomedical applications, pharmaceutical applications, Fourier transform infrared spectrum, amino acids, spherical morphology, topographical images, atomic force microscopy, field emission scanning electron microscopy, X‐ray fluorescence spectrum, transmission electron microscopy analysis, surface plasmon resonance, dynamic light scattering, 3‐(4, 5‐dimethyl‐2‐thiazolyl)‐2, 5‐diphenyl‐tetrazolium assay, cytotoxicity analysis, Pt     

Hyaluronidase-triggered anticancer drug and siRNA delivery from cascaded targeting nanoparticles for drug-resistant breast cancer therapy

Drug resistance renders standard chemotherapy ineffective in the treatment of connective tissue growth factor (CTGF)-overexpressing breast cancer.By co-embedding the breast tumor cell-penetrating peptide (PEGA-pVEC) and hyaluronic add (HA) as a targeting media,novel cascaded targeting nanoparticles (HACT NPs) were created on a rattle mesoporous silica (rmSiO2) scaffold for the pinpoint delivery of siRNAs along with an anticancer drug,aiming at overcoming the drug resistance of CTGF-overexpressing breast cancer in vivo.The targeting nanoparticles selectively accumulated in the vasculature under the guidance of the PEGA-pVEC peptide,cascaded by receptor-mediated endocytosis with the aid of another targeting agent,HA,presenting a greater in vivo tumor targeting ability than single targeting ligand vectors.In addition,an HA shell prevented the leakage of therapeutic drugs during the cargo transport process,until the hyaluronidase (HAase)-triggered degradation upon lysosomes entering,guaranteeing a controllable drug release inside the target cells.When the protective shell disintegrates,the released siRNA took charge to silence the gene associated with drug resistance,CTGF,thus facilitating doxorubicin-induced apoptosis.The cascaded targeting media (PEGA-pVEC and HA) advances precision-guided therapy in vivo,while the encapsulation of siRNAs into a chemotherapy drug delivery system provides an effident strategy for the treatment of drug resistance cancers.     

Synthesis of oleic acid-stabilized silver nanoparticles and analysis of their antibacterial activity

The development of new and simple green chemical methods for synthesizing colloidal solutions of functional nanoparticles is desirable for environment-friendly applications. In the present work, we report a feasible method for synthesizing colloidal solutions of silver nanoparticles (Ag NPs) based on the modified Tollens technique. The Ag NPs were stabilized by using oleic acid as a surfactant and were produced for the first time by the reduction of silver ammonium complex [Ag(NH₃)₂]⁺_(aq) by glucose with UV irradiation treatment. A stable and nearly monodisperse aqueous Ag NPs solution with average-sized particles (~ 9–10 nm) was obtained. The Ag NPs exhibited high antibacterial activity against both Gram-negative Escherichia Coli (E. coli) and Gram-positive Staphylococcus aureus bacteria. Electron microscopic images and analyses provided further insights into the interaction and bactericidal mechanism of the Ag NPs. The proposed method of synthesis is an effective way to produce highly bactericidal colloidal solutions for medical, microbiological, and industrial applications.     

Medicinal plants mediated the green synthesis of silver nanoparticles and their biomedical applications

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Green nano synthesis is a rapidly expanding field of interest in nanotechnology due to its feasibility, low toxicity, eco‐friendly nature, and long‐term viability. Some plants have long been used in medicine because they contain a variety of bioactive compounds. Silver has long been known for its antibacterial properties. Silver nanoparticles have taken a special place among other metal nanoparticles. Silver nanotechnology has a big impact on medical applications like bio‐coating, novel antimicrobial agents, and drug delivery systems. This review aims to provide a comprehensive understanding of the pharmaceutical qualities of medicinal plants, as well as a convenient guideline for plant‐based silver nanoparticles and their antimicrobial activity.