Potential theranostics application of bio-synthesized silver nanoparticles (4-in-1 system)

Anti-cancer and anti-oxidant properties of ethanolic leaf extract of Thymus vulgaris and its bio-functionalized silver nanoparticles

This study highlights the anti-oxidant and anti-cancer activities of bio-functionalized Thymus vulgaris silver nanoparticles (TVAgNPs) and bioactive compounds were compared using the human breast cancer T47D cell line. The aqueous ethanolic extract of T. vulgaris evaluated for chemical composition using the gas chromatography-mass spectrometer (GC-MS) analysis. The prepared TVAgNPs were determined by means of UV-Vis spectroscopy, FTIR spectroscopy, zeta potential, scanning electron microscopy, transmission electron microscopy, and energy-dispersed spectroscopy analysis. The T. vulgaris extract and TVAgNPs were studied for their in vitro anti-oxidant property by 2, 2-diphenyl, 1-picryl hydrazyl (DPPH) assay. Microscopic observations indicated spherical shaped and monodispersed nanoparticles and the average size of the nanoparticles was about 30 nm. Regarding the elemental composition profile of the TVAgNPs, the highest signal of silver (89.30%) was detected followed by other elements. An absorption peak was registered at 440 nm according to surface plasmon resonance (SPR) of the TVAgNPs in solution. A zeta potential of fabricated nanoparticles was approximately - 12.6 mV, indicating higher stability of the bio-functionalized TVAgNPs. The T. vulgaris extract and synthesized TVAgNPs were evaluated for their anti-cancer activity using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and Annexin V double staining with propidium iodide (PI) flow cytometric analysis toward T47D cells. The cytotoxicity properties of the bio-functionalized T. vulgaris AgNPs revealed that the sensitivity of T47D human breast cancer cells is high compared with T. vulgaris extract. The Annexin V/PI staining indicated that the fabricated TVAgNPs shows increased apoptosis in T47D cells as compared to untreated cells. Besides, the anti-oxidant activity of the TVAgNPs clarified a higher anti-radical-scavenging activity compared to Thymus vulgaris extract. Our data show that the potential biological activities of the bioactive constituents of T. vulgaris can be enhanced through bio-functionalized T. vulgaris AgNPs due to the bioorganic compounds that exist in the extract.

Novel Self-assembled Organic Nanoprobe for Molecular Imaging and Treatment of Gram-positive Bacterial Infection

Background: Increasing bacterial infections as well as a rise in bacterial resistance call for the development of novel and safe antimicrobial agents without inducing bacterial resistance. Nanoparticles (NPs) present some advantages in treating bacterial infections and provide an alternative strategy to discover new antibiotics. Here, we report the development of novel self-assembled fluorescent organic nanoparticles (FONs) with excellent antibacterial efficacy and good biocompatibility. Methods: Self-assembly of 1-(12-(pyridin-1-ium-1-yl)dodecyl)-4-(1,4,5-triphenyl-1H-imidazol-2-yl)pyridin-1-ium (TPIP) in aqueous solution was investigated using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The bacteria were imaged under a laser scanning confocal microscope. We evaluated the antibacterial efficacy of TPIP-FONsin vitro using sugar plate test. The antimicrobial mechanism was explored by SEM. The biocompatibility of the nanoparticles was examined using cytotoxicity test, hemolysis assay, and histological staining. We further tested the antibacterial efficacy of TPIP-FONsin vivo using the S. aureus-infected rats. Results: In aqueous solution, TPIP could self-assemble into nanoparticles (TPIP-FONs) with characteristic aggregation-induced emission (AIE). TPIP-FONs could simultaneously image gram-positive bacteria without the washing process. In vitro antimicrobial activity suggested that TPIP-FONs had excellent antibacterial activity against S. aureus (MIC = 2.0 µg mL^-1). Furthermore, TPIP-FONs exhibited intrinsic biocompatibility with mammalian cells, in particular, red blood cells. In vivo studies further demonstrated that TPIP-FONs had excellent antibacterial efficacy and significantly reduced bacterial load in the infectious sites. Conclusion: The integrated design of bacterial imaging and antibacterial functions in the self-assembled small molecules provides a promising strategy for the development of novel antimicrobial nanomaterials.

Potential anticancer activity of biogenic silver nanoparticles using leaf extract of Rhynchosia suaveolens: an insight into the mechanism

The present study reports a simple and eco-friendly synthesis of silver nanoparticles (AgNPs) using leaf extract of Rhynchosia suaveolens. UV-Vis analysis of R. suaveolens synthesized AgNPs (RS-AgNPs) showed surface plasmon resonance (SPR) peak at 426 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis revealed that RS-AgNPs were 10-30 nm in size with spherical shape. X-ray diffraction (XRD) analysis of RS-AgNPs confirmed the crystalline nature with face-centered cubic (FCC) lattice. Fourier transform infrared (FTIR) interprets that polyphenols and proteins take part in bioreduction and capping of RS-AgNPs. RS-AgNPs exhibited dose-dependent inhibition of proliferation of different cancer cells including DU145 and PC-3(human prostate carcinoma cell lines), SKOV3 (human ovarian carcinoma) and A549 (human lung adenocarcinoma)with IC₅₀ values of 4.35, 7.72, 4.2 and 24.7 μg/mL, respectively. The plausible reasons behind anticancer activity of RS-AgNPs were explained using different assays on the most susceptible SKOV3 cells. RS-AgNPs induced oxidative stress in SKOV3 cells by generating reactive oxygen species (ROS), enhancing lipid peroxidation (LPO) levels and decreasing glutathione (GSH) levels. RS-AgNPs induced the apoptosis of SKOV3 cells by up regulating the caspase-3, caspase -8, caspase -9, p53 and BAX and down regulating the antiapoptotic protein Bcl-2. Further, RS-AgNPs showed elevation of caspase 3/7 activity and also exhibited antimigratory effect by inhibiting the migration of SKOV3 cells into the wounded area. The findings suggested that biogenic RS-AgNPs provide an alternative approach to overcome several limitations of chemotherapy.

HPLC-DAD finger printing, antioxidant, cholinesterase, and α-glucosidase inhibitory potentials of a novel plant Olax nana

BACKGROUND

The medicinal importance of a novel plant Olax nana Wall. ex Benth. (family: Olacaceae) was revealed for the first time via HPLC-DAD finger printing, qualitative phytochemical analysis, antioxidant, cholinesterase, and α-glucosidase inhibitory assays.

METHODS

The crude methanolic extract of O. nana (ON-Cr) was subjected to qualitative phytochemical analysis and HPLC-DAD finger printing. The antioxidant potential of ON-Cr was assessed via 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) and hydrogen peroxide (H2O2) free radical scavenging assays. Furthermore, acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities were performed using Ellman's assay, while α- glucosidase inhibitory assay was carried out using a standard protocol.

RESULTS

The qualitative phytochemical analysis of ON-Cr revealed the presence of secondary metabolites like alkaloids, flavonoids, tannins, sterols, saponins and terpenoids. The HPLC-DAD finger printing revealed the presence of 40 potential compounds in ON-Cr. Considerable anti-radical activities was revealed by ON-Cr in the DPPH, ABTS and H2O2 free radical scavenging assays with IC50 values of 71.46, 72.55 and 92.33 μg/mL, respectively. Furthermore, ON-Cr showed potent AChE and BChE inhibitory potentials as indicated by their IC50 values of 33.2 and 55.36 μg/mL, respectively. In the α-glucosidase inhibition assay, ON-Cr exhibited moderate inhibitory propensity with an IC50 value of 639.89 μg/mL.

CONCLUSIONS

This study investigated Olax nana for the first time for detailed qualitative phytochemical tests, HPLC-DAD finger printing analysis, antioxidant, anticholinesterase and α-glucosidase inhibition assays. The antioxidant and cholinesterase inhibitory results were considerable and can provide scientific basis for further studies on the neuroprotective and anti-Alzheimer's potentials of this plant. ON-Cr may further be subjected to fractionation and polarity guided fractionation to narrow down the search for isolation of bioactive compounds.

A systematic review on silver nanoparticles-induced cytotoxicity: Physicochemical properties and perspectives

With the development of nanotechnology, silver nanoparticles (Ag-NPs) have become one of the most in-demand nanoparticles owing to their exponential number of uses in various sectors. The increased use of Ag-NPs-enhanced products may result in an increased level of toxicity affecting both the environment and living organisms. Several studies have used different model cell lines to exhibit the cytotoxicity of Ag-NPs, and their underlying molecular mechanisms. This review aimed to elucidate different properties of Ag-NPs that are responsible for the induction of cellular toxicity along with the critical mechanism of action and subsequent defense mechanisms observed in vitro. Our results show that the properties of Ag-NPs largely vary based on the diversified synthesis processes. The physiochemical properties of Ag-NPs (e.g., size, shape, concentration, agglomeration, or aggregation interaction with a biological system) can cause impairment of mitochondrial function prior to their penetration and accumulation in the mitochondrial membrane. Thus, Ag-NPs exhibit properties that play a central role in their use as biocides along with their applicability in environmental cleaning. We herein report a current review of the synthesis, applicability, and toxicity of Ag-NPs in relation to their detailed characteristics.

Mechanisms Underlying Neurotoxicity of Silver Nanoparticles

The potent antimicrobial properties of nanoparticulate silver (AgNPs) have led to broad interest in using them in a wide range of commercial and medical applications. Although numerous in vivo and in vitro studies have provided evidence of toxic effects, rapid commercialization of AgNP-based nanomaterials has advanced without characterization of their potential environmental and health hazards. There is evidence that AgNPs can be translocated from the blood to the brain, regardless the route of exposure, and accumulate in the brain over time. As the brain is responsible for basic physiological functions and controls all human activities, it is important to assess the hazardous influence of AgNPs released from widely used nanoproducts and possible side effects of AgNP-based therapies. A number of studies have suggested that the size, shape and surface coating, as well as rates of silver ion release and interactions with proteins are the key factors determining the neurotoxicity of AgNPs. AgNPs target endothelial cells forming the blood-brain barrier, neurons and glial cells and leads finally to oxidative stress-related cell death. In this chapter, we review in detail current data on the impact of AgNPs on the central nervous system and discuss the possible mechanisms of their neurotoxic effects.

Biomimetic production, characterisation, in vitro cytotoxic and anticancer assessment of aqueous extract‐mediated AgNPs of Teucrium stocksianum Boiss

Owing to the numerous biological applications, cost effectiveness and low cytotoxicity of the biomimetic nanoparticles (NPs), the authors optimised the production of silver NPs (AgNPs) using aqueous extract of Teucrium stocksianum Boiss. The NPs were characterised by ultraviolet‐visible (UV‐vis) spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS) and Fourier transform‐infrared spectroscopy (FTIR). The UV‐vis spectroscopy revealed a surface plasmon resonance (410‐440 nm) at an incubation temperature of 90°C when 1 mM Ag nitrate combined to 5 mg/ml extract concentration in the ratio of 1:10. DLS results show an average zeta size of ∼44.61 nm and zeta potential of −15.3 mV. SEM and XRD confirmed the high crystallinity and cubical symmetry with an average size below 100 nm. FTIR measurement shows the presence of various functional groups, responsible for the capping and reduction of Ag metal. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide cell viability assay shows that AgNPs are less cytotoxic to J774 and L929 cells as compared with enhanced anticancer activity with low IC50 concentrations (68.24 µg/ml) against Michigan Cancer Foundation‐7 (MCF‐7) cells. The ethidium bromide/acridine orange assay shows that the AgNPs kill the cell by apoptosis. Overall, the results show that AgNPs possesses potent anticancer activities.

In situ biosynthesis of ultrafine metal nanoparticles within a metal-organic framework for efficient heterogeneous catalysis

The synthesis of ultrafine, uniform, well-dispersed functional nanoparticles (NPs) under mild conditions in a controlled manner remains a great challenge. In biological systems, a well-defined biomineralization process is exploited, in which the control over NPs' size, shape and distribution is temporally and spatially regulated by a variety of biomolecules in a confined space. Inspired by this, we embedded proteins into metal-organic frameworks (MOFs) and explored a novel approach to synthesize metallic NPs by taking the synergy of protein-induced biomineralization process and space-confined effect of MOFs. The generation and growth of ultrafine metal NPs (Ag or Au) was induced by the entrapped lysozyme molecules and confined by the ZIF-8 pores. Due to the narrow size distribution and homogeneous spatial distribution of metal NPs, the as-synthesized NPs exhibit remarkably elevated catalytic activity. These findings demonstrate that MOFs can be loaded with specific proteins to selectively deposit inorganic NPs via biomimetic mineralization and these novel kinds of nanohybrid materials may find applications in catalysis, sensing and optics.

Biocompatible nickel-prussian blue@silver nanocomposites show potent antibacterial activities

Aim

Silver nanoparticles have long been used as potent antibacterial agents. However, toxicity concerns of silver nanoparticles have limited their successful clinical applications. Hence, development of silver-based novel biocompatible nanomaterials for antibacterial applications is a challenging task.

Materials & methods

Accordingly, in this work, we synthesized a biocompatible silver-based nanocomposite for antibacterial applications. The nanocompostie was characterized by several analytical techniques. The nanocomposite was further tested for its cytotoxicity in cells, chicken embryo and bacteria.

Results & Conclusion

Herein, we report a simple and cost-effective method for the synthesis of nickel-prussian blue@silver nanocomposites. The nanocomposite is highly stable and shows biocompatibility observed by in vitro assay and by ex vivo chicken embryonic angiogenesis assay. The nanocomposite exhibits profound antibacterial activity toward Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtillus) bacteria. The results altogether suggest the future potential applications of nickel-prussian blue@silver nanocomposite as an antibacterial agent.

Evidence based anti-osteoporosis effects of Periplaneta americana L on osteoblasts, osteoclasts, vascular endothelial cells and bone marrow derived mesenchymal stem cells

Background

Kangfuxin (KFX) is the ethanol extract of Periplaneta americana L, which has been widely used in the Traditional Chinese Medicine for the repair and regeneration of injured organ and tissues with long history. This study is to investigate the influence of KFX in the various cellular activities and evaluate the anti-osteoporosis potential of KFX.

Methods

The influence of the KFX in the cellular activities, including: 1) migration, osteocalcin secretion of osteoblasts; 2) apoptosis of osteoclasts; 3) migration and tube formation of human umbilical vein endothelial cell (HUVEC); and 4) proliferation, cell cycle regulation and migration of bone marrow mesenchymal stem cells (BMSCs), were investigated systematically.

Results

KFX was shown to significantly 1) Promote of the migration of osteoblasts, HUVEC, and BMSCs; 2) Increase the secretion of osteocalcin and mineralization of osteoblasts; 3) Accelerate the apoptosis of osteoclasts; 4) Stimulate the proliferation and regulate the cell cycle of BMSCs.

Conclusion

Taken together, these results provide the evidence for the osteogenesis, anti-osteoporosis and angiogenesis effects of KFX, with the mechanism of activating the bone formation through stimulating the osteoblasts and HUVECs, as well as inhibiting the bone absorption by inhibiting the osteoclasts activities. The KFX was definitely shown a promising bone turnover agent with great potential for anti-osteoporosis treatment.

Multifunctional biosynthesized silver nanoparticles exhibiting excellent antimicrobial potential against multi-drug resistant microbes along with remarkable anticancerous properties

This study demonstrates the therapeutic potential of silver nanoparticles (AgNPs), which were biosynthesized using the extracts of Citrus maxima plant. Characterization through UV-Vis spectrophotometry, Dynamic Light Scattering (DLS), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) confirmed the formation of AgNps in nano-size range. These nanoparticles exhibited enhanced antioxidative activity and showed commendable antimicrobial activity against wide range of microbes including multi-drug resistant bacteria that were later confirmed by TEM. These particles exhibited minimal toxicity when cytotoxicity study was performed on normal human lung fibroblast cell line as well as human red blood cells. It was quite noteworthy that these particles showed remarkable cytotoxicity on human fibrosarcoma and mouse melanoma cell line (B16-F10). Additionally, the apoptotic topographies of B16-F10 cells treated with AgNps were confirmed by using acridine orange and ethidium bromide dual dye staining, caspase-3 assay, DNA fragmentation assay followed by cell cycle analysis using fluorescence-activated cell sorting. Taken together, these results advocate promising potential of the biosynthesized AgNps for their use in therapeutic applications.

Noscapinoids bearing silver nanocrystals augmented drug delivery, cytotoxicity, apoptosis and cellular uptake in B16F1, mouse melanoma skin cancer cells

PURPOSE

Noscapine (Nos) and reduced brominated analogue of noscapine (Red-Br-Nos) prevent cellular proliferation and induce apoptosis in cancer cells either alone or in combination with other chemotherapeutic drugs. However, owing to poor physicochemical properties, Nos and Red-Br-Nos have demonstrated their anticancer activity at higher and multiple doses. Therefore, in present investigation, silver nanocrystals of noscapinoids (Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals) were customized to augment drug delivery, cytotoxicity, apoptosis and cellular uptake in B16F1 mouse melanoma cancer cells.

METHODS AND RESULTS

Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals were prepared separately by precipitation method. The mean particle size of Nos-Ag2+ nanocrystals was measured to be 25.33±3.52nm, insignificantly (P>0.05) different from 27.43±4.51nm of Red-Br-Nos-Ag2+ nanocrystals. Furthermore, zeta-potential of Nos-Ag2+ nanocrystals was determined to be -25.3±3.11mV significantly (P<0.05) different from -15.2±3.33mV of Red-Br-Nos-Ag2+ nanocrystals. The shape of tailored nanocrystals was slightly spherical and or irregular in shape. The architecture of Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals was crystalline in nature. FT-IR spectroscopy evinced the successful interaction of Ag2+ nanocrystals with Nos and Red-Br-Nos, respectively. The superior therapeutic efficacy of tailored nanocrystals was measured in terms of enhanced cytotoxicity, apoptosis and cellular uptake. The Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals exhibited an IC50 of 16.6μM and 6.5μM, significantly (P<0.05) lower than 38.5μM of Nos and 10.3μM of Red-Br-Nos, respectively. Finally, cellular morphological alterations in B16F1 cells upon internalization of Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals provided the evidences for accumulation within membrane-bound cytoplasmic vacuoles and in enlarged lysosomes and thus triggered mitochondria mediated apoptosis via caspase activation.

CONCLUSION

Preliminary investigations substantiated that Nos-Ag2+ nanocrystals and Red-Br-Nos-Ag2+ nanocrystals must be further explored and utilized for the delivery of noscapinoids to melanoma cancer cells.

Biosynthesis of Silver Nanoparticles from Protium serratum and Investigation of their Potential Impacts on Food Safety and Control

Silver nanoparticles play an integral part in the evolution of new antimicrobials against the broad ranges of pathogenic microorganisms. Recently, biological synthesis of metal nanoparticles using plant extracts has been successfully consummated. In the present study, the biosynthesis of silver nanoparticles (AgNPs) was conducted using the leaf extract of plant Protium serratum, having novel ethnomedicinal. The synthesized AgNPs were characterized using UV-Visible spectroscopy, dynamic light scattering spectroscopy (DLS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy. The DLS study revealed the surface charge of the resulted nanoparticles that was highly negative, i.e., −25.0 ± 7.84 mV and the size was 74.56 ± 0.46 nm. The phytochemical and FTIR analysis confirmed the role of water-soluble phyto-compounds for the reduction of silver ions to silver nanoparticles. The potential antibacterial activity of AgNPs was studied against the food borne pathogens viz. Pseudomonas aeruginosa (IC₅₀ = 74.26 ± 0.14 μg/ml), Escherichia coli (IC₅₀ = 84.28 ± 0.36 μg/ml), Bacillus subtilis (IC₅₀ = 94.43 ± 0.4236 μg/ml). The in vitro antioxidant potential of AgNPs was evaluated using 1, 1-diphenyl-2-picryl-hydrazil (IC₅₀ = 6.78 ± 0.15 μg/ml) and hydroxyl radical assay (IC₅₀ = 89.58 ± 1.15 μg/ml). In addition, the cytotoxicity of AgNPs was performed against fibroblast cell line L-929 to evaluate their biocompatibility. The overall results of the present investigation displayed the potential use of P. serratum leaf extract as a good bio-resource for the biosynthesis of AgNPs and their implementation in diverse applications, specifically as antibacterial agent in food packaging and preservation to combat against various food borne pathogenic bacteria along with its pharmaceutical and biomedical applications.

Curcumin loaded mesoporous silica: an effective drug delivery system for cancer treatment

In the present study, we report the delivery of anti-cancer drug curcumin to cancer cells using mesoporous silica materials. A series of mesoporous silica material based drug delivery systems (S2, S4 and S6) were first designed and developed through the amine functionalization of KIT-6, MSU-2 and MCM-41 followed by the loading of curcumin. The curcumin loaded materials were characterized with several physico-chemical techniques and thoroughly screened on cancer cells to evaluate their in vitro drug delivery efficacy. All the curcumin loaded silica materials exhibited higher cellular uptake and inhibition of cancer cell viability compared to pristine curcumin. The effective internalization of curcumin in cancer cells through the mesoporous silica materials initiated the generation of intracellular reactive oxygen species and the down regulation of poly ADP ribose polymerase (PARP) enzyme levels compared to free curcumin leading to the activation of apoptosis. This study shows that the anti-cancer activity of curcumin can be potentiated by loading onto mesoporous silica materials. Therefore, we strongly believe that mesoporous silica based curcumin loaded drug delivery systems may have future potential applications for the treatment of cancers.

Anisotropic noble metal nanoparticles: Synthesis, surface functionalization and applications in biosensing, bioimaging, drug delivery and theranostics

Anisotropic nanoparticles have fascinated scientists and engineering communities for over a century because of their unique physical and chemical properties. In recent years, continuous advances in design and fabrication of anisotropic nanoparticles have opened new avenues for application in various areas of biology, chemistry and physics. Anisotropic nanoparticles have the plasmon absorption in the visible as well as near-infrared (NIR) region, which enables them to be used for crucial applications such as biological imaging, medical diagnostics and therapy ("theranostics"). Here, we describe the progress in anisotropic nanoparticles achieved since the millennium in the area of preparation including various shapes and modification of the particle surface, and in areas of application by providing examples of applications in biosensing, bio-imaging, drug delivery and theranostics. Furthermore, we also explain various mechanisms involved in cellular uptake of anisotropic nanoparticles, and conclude with our opinion on various obstacles that limit their applications in biomedical field.

STATEMENT OF SIGNIFICANCE

Anisotropy at the molecular level has always fascinated scientists and engineering communities for over a century, however, the research on novel methods through which shape and size of nanoparticles can be precisely controlled has opened new avenues for anisotropic nanoparticles in various areas of biology, chemistry and physics. In this manuscript, we describe progress achieved since the millennium in the areas of preparation of various shapes of anisotropic nanoparticles, investigate various methods involved in modifying the surface of these NPs, and provide examples of applications in biosensing and bio-imaging, drug delivery and theranostics. We also present mechanisms involved in cellular uptake of nanoparticles, describe different methods of preparation of anisotropic nanoparticles including biomimetic and photochemical synthesis, and conclude with our opinion on various obstacles that limit their applications in biomedical field.

Governing factors affecting the impacts of silver nanoparticles on wastewater treatment

Silver nanoparticles (nanosilver or AgNPs) enter municipal wastewater from various sources, raising concerns about their potential adverse effects on wastewater treatment processes. We argue that the biological effects of silver nanoparticles at environmentally realistic concentrations (μgL^-1 or lower) on the performance of a full-scale municipal water resource recovery facility (WRRF) are minimal. Reactor configuration is a critical factor that reduces or even mutes the toxicity of silver nanoparticles towards wastewater microbes in a full-scale WRRF. Municipal sewage collection networks transform silver nanoparticles into silver(I)-complexes/precipitates with low ecotoxicity, and preliminary/primary treatment processes in front of biological treatment utilities partially remove silver nanoparticles to sludge. Microbial functional redundancy and microbial adaptability to silver nanoparticles also greatly alleviate the adverse effects of silver nanoparticles on the performance of a full-scale WRRF. Silver nanoparticles in a lab-scale bioreactor without a sewage collection system and/or a preliminary/primary treatment process, in contrast to being in a full scale system, may deteriorate the reactor performance at relatively high concentrations (e.g., mgL^-1 levels or higher). However, in many cases, silver nanoparticles have minimal impacts on lab-scale bioreactors, such as sequencing batch bioreactors (SBRs), especially when at relatively low concentrations (e.g., less than 1mgL^-1). The susceptibility of wastewater microbes to silver nanoparticles is species-specific. In general, silver nanoparticles have higher toxicity towards nitrifying bacteria than heterotrophic bacteria.

Green synthesis of silver nanoparticles via plant extracts: beginning a new era in cancer theranostics

With the development of the latest technologies, scientists are looking to design novel strategies for the treatment and diagnosis of cancer. Advances in medicinal plant research and nanotechnology have attracted many researchers to the green synthesis of metallic nanoparticles due to its several advantages over conventional synthesis (simple, fast, energy efficient, one pot processes, safer, economical and biocompatibility). Medicinally active plants have proven to be the best reservoirs of diverse phytochemicals for the synthesis of biogenic silver nanoparticles (AgNPs). In this review, we discuss mechanistic advances in the synthesis and optimization of AgNPs from plant extracts. Moreover, we have thoroughly discussed the recent developments and milestones achieved in the use of biogenic AgNPs as cancer theranostic agents and their proposed mechanism of action. Anticipating all of the challenges, we hope that biogenic AgNPs may become a potential cancer theranostic agent in the near future.

Amplified Fluorescence from Polyfluorene Nanoparticles with Dual State Emission and Aggregation Caused Red Shifted Emission for Live Cell Imaging and Cancer Theranostics

A newly synthesized polyfluorene derivative with pendant di(2-picolyl)amine (PF-DPA) shows dual state emission and aggregation caused red shifted emission that was utilized for cell imaging and cancer theranostics. PF-DPA was nontoxic to normal cells but showed cytotoxicity against cancer cells, suggesting its utility for cancer therapy. PF-DPA exhibits a large and unique red shifted emission at 556 nm at higher water ratio of THF:H₂O (10:90) due to the formation of polymer nanoparticles or PDots spontaneously by intra- and intermolecular self-assembly induced aggregation. Dual state emission and aggregation caused red shifted emission (>100 nm) in PF-DPA homopolymer nanoparticles is very unique and attributed to the combined effect of intramolecular planarization and J-type aggregate formation in the PDots (25 ± 5 nm). The PF-DPA PDots exhibit bright green and orange fluorescence with exceptional live cell imaging properties and potential applications in cancer theranostics due to their selective cytotoxic nature toward cancer cells.

Biogenesis of silver nanoparticles using endophytic fungus Pestalotiopsis microspora and evaluation of their antioxidant and anticancer activities

An endophytic fungal strain isolated from the leaves of Gymnema sylvestre was identified as Pestalotiopsis microspora VJ1/VS1 based on nucleotide sequencing of internal transcribed spacer region (ITS 1-5.8S-ITS 2) of 18S rRNA gene (NCBI accession number KX213894). In this study, an efficient and ecofriendly approach has been reported for the synthesis of silver nanoparticles (AgNPs) using aqueous culture filtrate of P. microspora. Ultraviolet-visible analysis confirmed the synthesis of AgNPs by showing characteristic absorption peak at 435 nm. Fourier transform infrared spectroscopy analysis revealed the presence of phenolic compounds and proteins in the fungal filtrate, which are plausibly involved in the biosynthesis and capping of AgNPs. Transmission electron microscopy (TEM) showed that the AgNPs were spherical in shape of 2-10 nm in size. Selected area electron diffraction and X-ray diffraction studies determined the crystalline nature of AgNPs with face-centered cubic (FCC) lattice phase. Dynamic light scattering analysis showed that the biosynthesized AgNPs possess high negative zeta potential value of -35.7 mV. Biosynthesized AgNPs were proved to be potential antioxidants by showing effective radical scavenging activity against 2,2'-diphenyl-1-picrylhydrazyl and H2O2 radicals with IC50 values of 76.95±2.96 and 94.95±2.18 µg/mL, respectively. The biosynthesized AgNPs exhibited significant cytotoxic effects against B16F10 (mouse melanoma, IC50 =26.43±3.41 µg/mL), SKOV3 (human ovarian carcinoma, IC50 =16.24±2.48 µg/mL), A549 (human lung adenocarcinoma, IC50 =39.83±3.74 µg/mL), and PC3 (human prostate carcinoma, IC50 =27.71±2.89 µg/mL) cells. The biosynthesized AgNPs were found to be biocompatible toward normal cells (Chinese hamster ovary cell line, IC50 =438.53±4.2 µg/mL). Cytological observations on most susceptible SKOV3 cells revealed concentration-dependent apoptotic changes that include cell membrane blebbing, cell shrinkage, pyknotic nuclei, karyorrhexis followed by destructive fragmentation of nuclei. The results together in this study strongly provided a base for the development of potential and versatile biomedical applications of biosynthesized AgNPs in the near future.

Synthesis and Characterization of Sygyzium cumini Nanoparticles for Its Protective Potential in High Glucose-Induced Cardiac Stress: a Green Approach

There exists a complex and multifactorial relationship between diabetes and cardiovascular disease. Hyperglycemia is an important factor imposing damage (glucose toxicity) on cardiac cell leading to diabetic cardiomyopathy. There are substantial clinical evidences on the adverse effects of conventional therapies in the prevention/treatment of diabetic cardiovascular complications. Currently, green-synthesized nanoparticles have emerged as a safe, efficient, and inexpensive alternative for therapeutic uses. The present study discloses the silver nanoparticle biosynthesizing capability and cardioprotective potential of Syzygium cumini seeds already reported to have antidiabetic properties. Newly generated silver nanoparticles S. cumini MSE silver nanoparticles (SmSNPs) were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), zeta sizer, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Using methanolic extract of S. cumini seeds, an average size of 40-100-nm nanoparticles with 43.02 nm and -19.6 mV zeta potential were synthesized. The crystalline nature of SmSNPs was identified by using XRD. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assays revealed the antioxidative potential to be 66.87 (±0.7) % and 86.07 (±0.92) % compared to 60.29 (±0.02) % and 85.67 (±1.27) % for S. cumini MSE. In vitro study on glucose-stressed H9C2 cardiac cells showed restoration in cell size, nuclear morphology, and lipid peroxide formation upon treatment of SmSNPs. Our findings concluded that S. cumini MSE SmSNPs significantly suppress the glucose-induced cardiac stress in vitro by maintaining the cellular integrity and reducing the oxidative damages therefore establishing its therapeutic potential in diabetic cardiomyopathy.

Multi-functional nano silver: A novel disruptive and theranostic agent for pathogenic organisms in real-time

The present study was aimed at evaluating the fluorescence property, sporicidal potency against Bacillus and Clostridium endospores, and surface disinfecting ability of biogenic nano silver. The nano silver was synthesized using an actinobacterial cell-filtrate. The fluorescence property as well as imaging facilitator potency of this nano silver was verified adopting spectrofluorometer along with fluorescent and confocal laser scanning microscope wherein strong emission and bright green fluorescence, respectively, on the entire spore surface was observed. Subsequently, the endospores of B. subtilis, B. cereus, B. amyloliquefaciens, C. perfringens and C. difficile were treated with physical sporicides, chemical sporicides and nano silver, in which the nano silver brought about pronounced inhibition even at a very low concentration. Finally, the environmental surface-sanitizing potency of nano silver was investigated adopting cage co-contamination assay, wherein vital organs of mice exposed to the nano silver-treated cage did not show any signs of pathological lesions, thus signifying the ability of nano silver to completely disinfect the spore or reduce the count required for infection. Taken these observations together, we have shown the multi-functional biological properties of the nano silver, synthesized using an actinobacterial cell-filtrate, which could be of application in advanced diagnostics, biomedical engineering and therapeutics in the near future.

Silver Nanoparticle-Mediated Cellular Responses in Various Cell Lines: An in Vitro Model

Silver nanoparticles (AgNPs) have attracted increased interest and are currently used in various industries including medicine, cosmetics, textiles, electronics, and pharmaceuticals, owing to their unique physical and chemical properties, particularly as antimicrobial and anticancer agents. Recently, several studies have reported both beneficial and toxic effects of AgNPs on various prokaryotic and eukaryotic systems. To develop nanoparticles for mediated therapy, several laboratories have used a variety of cell lines under in vitro conditions to evaluate the properties, mode of action, differential responses, and mechanisms of action of AgNPs. In vitro models are simple, cost-effective, rapid, and can be used to easily assess efficacy and performance. The cytotoxicity, genotoxicity, and biocompatibility of AgNPs depend on many factors such as size, shape, surface charge, surface coating, solubility, concentration, surface functionalization, distribution of particles, mode of entry, mode of action, growth media, exposure time, and cell type. Cellular responses to AgNPs are different in each cell type and depend on the physical and chemical nature of AgNPs. This review evaluates significant contributions to the literature on biological applications of AgNPs. It begins with an introduction to AgNPs, with particular attention to their overall impact on cellular effects. The main objective of this review is to elucidate the reasons for different cell types exhibiting differential responses to nanoparticles even when they possess similar size, shape, and other parameters. Firstly, we discuss the cellular effects of AgNPs on a variety of cell lines; Secondly, we discuss the mechanisms of action of AgNPs in various cellular systems, and try to elucidate how AgNPs interact with different mammalian cell lines and produce significant effects; Finally, we discuss the cellular activation of various signaling molecules in response to AgNPs, and conclude with future perspectives on research into AgNPs.

Gold nanoparticle-conjugated quercetin inhibits epithelial-mesenchymal transition, angiogenesis and invasiveness via EGFR/VEGFR-2-mediated pathway in breast cancer

OBJECTIVES

Epidermal growth factor plays a critical role in breast malignancies by enhancing cell proliferation, invasion, angiogenesis and metastasis. Epithelial-mesenchymal transition (EMT) is a crucial process by which epithelial cells lose polarity and acquire migratory mesenchymal properties. Gold nanoparticles are an efficient drug delivery vehicle for carrying chemotherapeutic agents to target cancer cells and quercetin is an anti-oxidative flavonoid known with potent anti-malignant cell activity.

MATERIALS AND METHODS

Cell viability was assessed by MTT assay, and protein expression was examined by Western blotting and immunocytochemistry. Cell invasion was monitored using invasion chambers, and cell migration was analysed by scratch wound-healing assay. In vitro and ex vivo angiogenesis studies were performed by capillary-like tube formation assay and chick embryo angiogenesis assay (CEA). 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary carcinoma in Sprague-Dawley rats.

RESULTS

We observed a significant reduction in protein expression of vimentin, N-cadherin, Snail, Slug, Twist, MMP-2, MMP-9, p-EGFR, VEGFR-2, p-PI3K, Akt and p-GSK3β, and enhanced E-cadherin protein expression in response to AuNPs-Qu-5 treatment. AuNPs-Qu-5 inhibited migration and invasion of MCF-7 and MDA-MB-231 cells compared to free quercetin. AuNPs-Qu-5-treated HUVECs had reduced cell viability and capillary-like tube formation. In vitro and in vivo angiogenesis assays showed that AuNPs-Qu-5 suppressed tube and new blood vessel formation. Treatment with AuNPs-Qu-5 impeded tumour growth in DMBA-induced mammary carcinoma in SD rats compared to treatment with free quercetin.

CONCLUSION

Our results suggest that AuNPs-Qu-5 inhibited EMT, angiogenesis and metastasis of the breast cancer cells tested by targeting the EGFR/VEGFR-2 signalling pathway.

Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches

Recent advances in nanoscience and nanotechnology radically changed the way we diagnose, treat, and prevent various diseases in all aspects of human life. Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in biomedical applications. AgNPs play an important role in nanoscience and nanotechnology, particularly in nanomedicine. Although several noble metals have been used for various purposes, AgNPs have been focused on potential applications in cancer diagnosis and therapy. In this review, we discuss the synthesis of AgNPs using physical, chemical, and biological methods. We also discuss the properties of AgNPs and methods for their characterization. More importantly, we extensively discuss the multifunctional bio-applications of AgNPs; for example, as antibacterial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anti-cancer agents, and the mechanism of the anti-cancer activity of AgNPs. In addition, we discuss therapeutic approaches and challenges for cancer therapy using AgNPs. Finally, we conclude by discussing the future perspective of AgNPs.

Combination of salinomycin and silver nanoparticles enhances apoptosis and autophagy in human ovarian cancer cells: an effective anticancer therapy

Ovarian cancer is one of the most important malignancies, and the origin, detection, and pathogenesis of epithelial ovarian cancer remain elusive. Although many cancer drugs have been developed to dramatically reduce the size of tumors, most cancers eventually relapse, posing a critical problem to overcome. Hence, it is necessary to identify possible alternative therapeutic approaches to reduce the mortality rate of this devastating disease. To identify alternative approaches, we first synthesized silver nanoparticles (AgNPs) using a novel bacterium called Bacillus clausii. The synthesized AgNPs were homogenous and spherical in shape, with an average size of 16–20 nm, which are known to cause cytotoxicity in various types of human cancer cells, whereas salinomycin (Sal) is able to kill cancer stem cells. Therefore, we selected both Sal and AgNPs to study their combined effect on apoptosis and autophagy in ovarian cancer cells. The cells treated with either Sal or AgNPs showed a dose-dependent effect with inhibitory concentration (IC)-50 values of 6.0 µM and 8 µg/mL for Sal and AgNPs, respectively. To determine the combination effect, we measured the IC₂₅ values of both Sal and AgNPs (3.0 µM and 4 µg/mL), which showed a more dramatic inhibitory effect on cell viability and cell morphology than either Sal or AgNPs alone. The combination of Sal and AgNPs had more pronounced effect on cytotoxicity and expression of apoptotic genes and also significantly induced the accumulation of autophagolysosomes, which was associated with mitochondrial dysfunction and loss of cell viability. Our data show a strong synergistic interaction between Sal and AgNPs in tested cancer cells. The combination treatment increased the therapeutic potential and demonstrated the relevant targeted therapy for the treatment of ovarian cancer. Furthermore, we provide, for the first time, a mode of action for Sal and AgNPs in ovarian cancer cells: enhanced apoptosis and autophagy.

Therapeutic application of anti-angiogenic nanomaterials in cancers

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, plays a vital role in physiological and pathological processes (embryonic development, wound healing, tumor growth and metastasis). The overall balance of angiogenesis inside the human body is maintained by pro- and anti-angiogenic signals. The processes by which drugs inhibit angiogenesis as well as tumor growth are called the anti-angiogenesis technique, a most promising cancer treatment strategy. Over the last couple of decades, scientists have been developing angiogenesis inhibitors for the treatment of cancers. However, conventional anti-angiogenic therapy has several limitations including drug resistance that can create problems for a successful therapeutic strategy. Therefore, a new comprehensive treatment strategy using antiangiogenic agents for the treatment of cancer is urgently needed. Recently researchers have been developing and designing several nanoparticles that show anti-angiogenic properties. These nanomedicines could be useful as an alternative strategy for the treatment of various cancers using anti-angiogenic therapy. In this review article, we critically focus on the potential application of anti-angiogenic nanomaterial and nanoparticle based drug/siRNA/peptide delivery systems in cancer therapeutics. We also discuss the basic and clinical perspectives of anti-angiogenesis therapy, highlighting its importance in tumor angiogenesis, current status and future prospects and challenges.

Bio-effect of nanoparticles in the cardiovascular system

Nanoparticles (NPs; < 100 nm) are increasingly being applied in various fields due to their unique physicochemical properties. The increase in human exposure to NPs has raised concerns regarding their health and safety profiles. The potential correlation between NP exposure and several cardiovascular (CV) events has been demonstrated. The aim of this review is to provide a comprehensive evaluation of the current knowledge regarding the bio-toxic impacts of titanium oxide, silver, silica, carbon black, carbon nanotube, and zinc oxide NPs exposure on the CV system in terms of in vivo and in vitro experiments, which is not fully understood presently. Moreover, the potential toxic mechanisms of NPs in the CV system that are still being questioned are elaborately discussed, and the underlying capacity of NPs used in medicine for CV events are summarized. It will be an important instrument to extrapolate relevant data for human CV risk evaluation and management. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2881-2897, 2016.

Sulfonated Schiff base Sn(IV) complexes as potential anticancer agents

Syntheses, crystal structures and biological activities of the diphenoxo-bridged diorgano dinuclear Sn(IV) compounds [Sn(Et)₂(HL)(H₂O)]₂ (1) and [Sn(n-Bu)₂(HL)(H₂O)]₂ (2) derived from the Schiff base 2-[(2,3-dihydroxyphenyl)methylideneamino]benzenesulfonic acid trihydrate (H₃L·3H₂O) are described. The monoprotonated form (HL^2-) of the Schiff base behaves as O,O'-bidentate ligand, chelating the metal by the two phenoxo oxygen atoms. The hexacoordinated metal centres in 1 and 2 are bridged by a phenoxo oxygen and the remaining coordination positions are fulfilled by the other phenoxo oxygen, two organic groups (ethyl for 1 and n-butyl for 2) and a water molecule. A two dimensional zigzag sheet in 1 and three dimensional polymeric networks in H₃L·3H₂O and 2 are stabilized by a number of non-covalent, H-bonding and π⋯π stacking interactions. The DNA binding activities of these complexes have been studied by UV-vis and fluorescence spectroscopies. Their antiproliferative efficacies have been evaluated on A-549, HeLa and MDA-MB-231 cancer cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. IC₅₀ values (1.35±0.23, 2.43±0.54 and 1.74±0.04μM for 2) are indicative of a substantial cytotoxicity of 2, mainly towards the A-549 lung cancer cell line. The greater antiproliferative efficacy of 2has further been studied by fluorescence activated cell sorting (FACS) and nuclear morphology by Hoechst/propidium iodide (PI) double staining method. The possible mode of the apoptotic pathway for 2has been substantiated by the reactive oxygen species (ROS) generation studies.

Polysaccharide-capped silver Nanoparticles inhibit biofilm formation and eliminate multi-drug-resistant bacteria by disrupting bacterial cytoskeleton with reduced cytotoxicity towards mammalian cells

Development of effective anti-microbial therapeutics has been hindered by the emergence of bacterial strains with multi-drug resistance and biofilm formation capabilities. In this article, we report an efficient green synthesis of silver nanoparticle (AgNP) by in situ reduction and capping with a semi-synthetic polysaccharide-based biopolymer (carboxymethyl tamarind polysaccharide). The CMT-capped AgNPs were characterized by UV, DLS, FE-SEM, EDX and HR-TEM. These AgNPs have average particle size of ~20-40 nm, and show long time stability, indicated by their unchanged SPR and Zeta-potential values. These AgNPs inhibit growth and biofilm formation of both Gram positive (B. subtilis) and Gram negative (E. coli and Salmonella typhimurium) bacterial strains even at concentrations much lower than the minimum inhibitory concentration (MIC) breakpoints of antibiotics, but show reduced or no cytotoxicity against mammalian cells. These AgNPs alter expression and positioning of bacterial cytoskeletal proteins FtsZ and FtsA. CMT-capped AgNPs can effectively block growth of several clinical isolates and MDR strains representing different genera and resistant towards multiple antibiotics belonging to different classes. We propose that the CMT-capped AgNPs can have potential bio-medical application against multi-drug-resistant microbes with minimal cytotoxicity towards mammalian cells.