Interaction of multi-functional silver nanoparticles with living cells

Recent Advances in Photodynamic Therapy: Metal-Based Nanoparticles as Tools to Improve Cancer Therapy

Cancer remains a significant global health challenge, with traditional therapies like surgery, chemotherapy, and radiation often accompanied by systemic toxicity and damage to healthy tissues. Despite progress in treatment, these approaches have limitations such as non-specific targeting, systemic toxicity, and resistance development in cancer cells. In recent years, nanotechnology has emerged as a revolutionary frontier in cancer therapy, offering potential solutions to these challenges. Nanoparticles, due to their unique physical and chemical properties, can carry therapeutic payloads, navigate biological barriers, and selectively target cancer cells. Metal-based nanoparticles, in particular, offer unique properties suitable for various therapeutic applications. Recent advancements have focused on the integration of metal-based nanoparticles to enhance the efficacy and precision of photodynamic therapy. Integrating nanotechnology into cancer therapy represents a paradigm shift, enabling the development of strategies with enhanced specificity and reduced off-target effects. This review aims to provide a comprehensive understanding of the pivotal role of metal-based nanoparticles in photodynamic therapy. We explore the mechanisms, biocompatibility, and applications of metal-based nanoparticles in photodynamic therapy, highlighting the challenges and the limitations in their use, as well as the combining of metal-based nanoparticles/photodynamic therapy with other strategies as a synergistic therapeutic approach for cancer treatment.

Systematic Investigation of Cellular Response to Hydroxyl Group Orientation Differences on Gold Glyconanoparticles

Nanoparticle (NP) surfaces act as the interface as they interact with living systems and play a critical role in defining their cellular response. The nature of these interactions should be well understood to design safer and more effective NPs to be used in a wide range of biomedical applications. At the moment, it is not clear how a subtle change in surface chemistry will affect an NP's behavior in a biological system. Thus, understanding the role of such a small change is critical and may allow one to fine-tune a biological response. In this study, the cellular response to -OH orientation differences generated on gold glyconanoparticles, which are recently considered promising therapeutic agents as they mimic a glycocalyx, is investigated. As model molecules, glucose and mannose (C2 epimer) as monosaccharides and lactose and maltose (galactose and glucose as free units, C4 epimer) as disaccharides were chosen to monitor the cellular response in A549, BEAS-2b, and MDA-MB-231 cells through cellular uptake, cytotoxicity, and cell cycle progression. The three cell lines gave various and remarkable cellular responses to the same subtle -OH differences on gold glyconanoparticles, and it is determined that not only -OH orientation differences but also the number of saccharides on gold glyconanoparticles affect the cellular response. It was shown that mannose (C2 epimer to glucose) was significant with the promise of being a therapeutic agent for lung cancer therapy, whereas the toxicological profile of MDA-MB-231 cells was affected by AuNPs-glucose the most. This study demonstrates that clearly small chemical alterations on a NP surface can result in a significant cellular response. It can be concluded that the -OH orientation at the second and fourth carbon of a carbohydrate ring has a critical role in designing and engineering novel gold glyconanoparticles (consisting of monolayer mono- or disaccharides) for a specific cancer therapy.

Functionalized Metal Nanoparticles in Cancer Therapy

Currently, there are many studies on the application of nanotechnology in therapy. Metallic nanoparticles are promising nanomaterials in cancer therapy; however, functionalization of these nanoparticles with biomolecules has become relevant as their effect on cancer cells is considerably increased by photothermal and photodynamic therapies, drug nanocarriers, and specificity by antibodies, resulting in new therapies that are more specific against different types of cancer. This review describes studies on the effect of functionalized palladium, gold, silver and platinum nanoparticles in the treatment of cancer, these nanoparticles themselves show an anticancer effect. This effect is further enhanced when the NPs are functionalized with either antibodies, DNA, RNA, peptides, proteins, or folic acid and other molecules. These NPs can penetrate the cell and accumulate in the tumor tissue, resulting in a cytotoxic effect through the generation of ROS, the induction of apoptosis, cell cycle arrest, DNA fragmentation, and a photothermal effect. NP-based therapy is a new strategy that can be used synergistically with chemotherapy and radiotherapy to achieve more effective therapies and reduce side effects.

Dextran 40 hybrid biomimetic bismuth-nanoflower designed for NIR II-triggered hypoxic tumor thermoradiotherapy via macrophage escape

At present, NIR-II-triggered photothermal biomedical applications are limited by complex synthesis reactions, mediocre photothermal conversion efficiency, and difficult degradation. Herein, we prepared biodegradable Bi flower-like nanoparticles (phospholipid-modified Bi nanoflowers, BNFs) with high photothermal conversion efficiency (∼33.52 %) in NIR-II by a simple method and then modified them with the red blood cell membrane and dextran 40 (DRBCM) to improve their in vitro stability, to escape macrophages clearance and to enhance tumor accumulation. Dextran coating onto the surface of particles as a dispersant shell stabilizes inorganic particles by maintaining the surface charges and creating steric repulsions upon compression of neighboring polymer chains. In vitro and in vivo experiments proved that combined thermoradiotherapy of DRBCM-BNFs exhibited significantly enhanced tumor inhibition efficacy than monotherapy with good biocompatibility and low toxicity due to its biodegradability. Furthermore, the mechanism studies demonstrated that DRBCM-BNFs could serve as a nano sensitizer to promote the thermoradiotherapy under NIR-II illumination and X-ray irradiation, by downregulating heat shock protein 70 (HSP70) and phosphorylated-p65 (p-p65) to reduce the thermal resistance and radioresistance of tumor cells and increasing the expression of apoptosis-related protein cleaved caspase-3. In conclusion, DRBCM-BNFs could be a promising green delivery platform for the sensitization of synergistic thermoradiotherapy.

Synthesis of silver nanoparticles using Eucommia ulmoides extract and their potential biological function in cosmetics

Silver nanoparticles (AgNPs) synthesized from plant extracts have recently emerged as a rapidly growing field with numerous applications in pharmaceutical and clinical contexts. The purpose of this research is to come up with a novel method for the biosynthesis of silver nanoparticles that use Eucommia ulmoides leaf extract as a reducing agent. The synthesis of AgNPs was confirmed using UV-vis spectroscopy, and the properties of AgNPs were characterized using Transmission Electron Microscope, Fourier Infrared Spectrometer, X-ray diffraction, Thermogravimetric Analysis, and Zeta potential. The results showed that the AgNPs exhibited a characteristic absorption peak at 430 nm, their diameter ranged from 4 nm to 52 nm, and C, O, and Cl elements, which might represent flavonoids and phenolic components absorbed on the surface of AgNPs. The zeta potential of AgNPs was found to be −30.5 mV, which indicates repulsion among AgNPs and they have good dispersion stability. AgNPs have been found to suppress the tyrosinase activity both in mushroom tyrosinase and A375 cells, as well as diminish ROS formation in HaCat cells. According to this study, AgNPs is a novel material that can enhance skin health by preventing melanin development.

Electrospun alginate mats embedding silver nanoparticles with bioactive properties

Polysaccharide-based composites embedding silver nanoparticles (AgNPs) represent a promising alternative to common antimicrobial materials because of the effective, broad-spectrum biocidal properties of AgNPs combined with the biocompatibility and environmental safety of the naturally occurring polymeric component. In this work, AgNPs stabilized with alginate chains (Alg@AgNPs) were successfully synthesized in situ within the polysaccharide solution through a wet chemical approach carried out at different concentrations of the silver salt precursor. Once obtained, the aqueous suspensions were electrospun to prepare non-woven membranes, showing a homogeneous nanostructured texture (with fiber diameter between 100 and 150 nm), which was found to be influenced by the size (between 20 and 35 nm) of the embedded metal nanoparticles. The biocidal potential of the nanocomposite mats was preliminarily tested against Gram-negative E. coli. The results showed that the antimicrobial response of the investigated samples occurred within a day of incubation and can be observed for AgNPs content in the polysaccharide fibers far below the nanomolar regime.

Green Ag/AgCl as an Effective Plasmonic Photocatalyst for Degradation and Mineralization of Methylthioninium Chloride

A green synthesis of Ag/AgCl with an exceptional SPR and photocatalysis property is greatly benefit to the environmental application especially pollutant removal. In this work, a novel green plasmonic photocatalysis of Ag/AgCl nanocatalyst using aqueous garlic extract (Allium Sativum L.) was successfully synthesized. The allicin and organosulfur compounds in the garlic can act as reducing agents in the green synthesis process. The nanocatalyst properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffractometer. The light-harvesting property was investigated by UV-vis absorption spectra which reveals its visible light absorption capability owing surface plasmon resonance behavior of Ag nanoparticles. The degradation and mineralization of methylthioninium chloride (MC) using this photocatalyst were evaluated under visible light and natural solar irradiation. Surface plasmon resonance of Ag nanoparticles and the presence of organosulfur from the garlic extract facilitated adsorption of MC onto the particle surface, promoting greater degradation. The photocatalytic reaction under visible light can be explained by the pseudo first-order pattern with the highest reaction rate of 0.5829 mg L−1 min−1 at pH 10. The photocatalytic activity of the Ag/AgCl under the natural sunlight reached 90% and 75% for MC and total organic carbon (TOC), respectively. The intermediate products detected during MC degradation under sunlight irradiation before final transformation to CO2, H2O, HNO3, and H2SO4 were also reported. The simplicity of Ag/AgCl green synthesis with the photocatalysis properties under visible light and sunlight can offer the convenience of applying these nanoparticles for pollutant removal in water treatment processes.

Synthesis and Characterization of Magnetic Composite Theragnostics by Nano Spray Drying

Composites of magnetite nanoparticles encapsulated with polymers attract interest for many applications, especially as theragnostic agents for magnetic hyperthermia, drug delivery, and magnetic resonance imaging. In this work, magnetite nanoparticles were synthesized by coprecipitation and encapsulated with different polymers (Eudragit S100, Pluronic F68, Maltodextrin, and surfactants) by nano spray drying technique, which can produce powders of nanoparticles from solutions or suspensions. Transmission and scanning electron microscopy images showed that the bare magnetite nanoparticles have 10.5 nm, and after encapsulation, the particles have approximately 1 μm, with size and shape depending on the material’s composition. The values of magnetic saturation by SQUID magnetometry and mass residues by thermogravimetric analysis were used to characterize the magnetic content in the materials, related to their magnetite/polymer ratios. Zero-field-cooling and field-cooling (ZFC/FC) measurements showed how blocking temperatures of the powders of the composites are lower than that of bare magnetite, possibly due to lower magnetic coupling, being an interesting system to study magnetic interactions of nanoparticles. Furthermore, studies of cytotoxic effect, hydrodynamic size, and heating capacity for hyperthermia (according to the application of an alternate magnetic field) show that these composites could be applied as a theragnostic material for a non-invasive administration such as nasal.

Cancer Therapy by Silver Nanoparticles: Fiction or Reality?

As an emerging new class, metal nanoparticles and especially silver nanoparticles hold great potential in the field of cancer biology. Due to cancer-specific targeting, the consequently attenuated side-effects and the massive anti-cancer features render nanoparticle therapeutics desirable platforms for clinically relevant drug development. In this review, we highlight those characteristics of silver nanoparticle-based therapeutic concepts that are unique, exploitable, and achievable, as well as those that represent the critical hurdle in their advancement to clinical utilization. The collection of findings presented here will describe the features that distinguish silver nanoparticles from other anti-cancer agents and display the realistic opportunities and implications in oncotherapeutic innovations to find out whether cancer therapy by silver nanoparticles is fiction or reality.

One-Pot Preparation of Metal-Polymer Nanocomposites in Irradiated Aqueous Solutions of 1-Vinyl-1,2,4-triazole and Silver Ions

Metal-polymer nanocomposite polyvinyltriazole-silver nanoparticles were obtained using one-pot synthesis in irradiated aqueous solutions of 1-vinyl-1,2,4-triazole (VT) and silver ions. Gel permeation chromatography data show that upon radiation initiation, the molecular weight of poly(1-vinyl-1,2,4-triazole) increases with increasing monomer concentration. To study the kinetics of polymerization and the features of the radiation-chemical formation of nanoparticles, UV-Vis spectroscopy was used. TEM images show a relatively small average size of the forming nanoparticles (2-3 nm) and a narrow size distribution, which shows the effective stabilization of nanoparticles by triazole substituents at a molar ratio of VT and silver ions of 25/1. The addition of ethyl alcohol was used to increase the efficiency of synthesis and suppress the crosslinking of macromolecules in solution. The results of the work show that aqueous-alcoholic solutions of 1 wt.% VT can be used to obtain soluble nanocomposite materials. 10 wt.% monomer solutions have prospects for use in the preparation of polymer gels filled with nanoparticles.

Silver Nanoparticles Derived by Artemisia arborescens Reveal Anticancer and Apoptosis-Inducing Effects

The fight against cancer is one of the main challenges for medical research. Recently, nanotechnology has made significant progress, providing possibilities for developing innovative nanomaterials to overcome the common limitations of current therapies. In this context, silver nanoparticles (AgNPs) represent a promising nano-tool able to offer interesting applications for cancer research. Following this path, we combined the silver proprieties with Artemisia arborescens characteristics, producing novel nanoparticles called Artemisia-AgNPs. A "green" synthesis method was performed to produce Artemisia-AgNPs, using Artemisia arborescens extracts. This kind of photosynthesis is an eco-friendly, inexpensive, and fast approach. Moreover, the bioorganic molecules of plant extracts improved the biocompatibility and efficacy of Artemisia-AgNPs. The Artemisia-AgNPs were fully characterized and tested to compare their effects on various cancer cell lines, in particular HeLa and MCF-7. Artemisia-AgNPs treatment showed dose-dependent growth inhibition of cancer cells. Moreover, we evaluated their impact on the cell cycle, observing a G1 arrest mediated by Artemisia-AgNPs treatment. Using a clonogenic assay after treatment, we observed a complete lack of cell colonies, which demonstrated cell reproducibility death. To have a broader overview on gene expression impact, we performed RNA-sequencing, which demonstrated the potential of Artemisia-AgNPs as a suitable candidate tool in cancer research.

Glyconanofluorides as Immunotracers with a Tunable Core Composition for Sensitive Hotspot Magnetic Resonance Imaging of Inflammatory Activity

Nature-inspired nanosized formulations based on an imageable, small-sized inorganic core scaffold, on which biomolecules are assembled to form nanobiomimetics, hold great promise for both early diagnostics and developed therapeutics. Nevertheless, the fabrication of nanobiomimetics that allow noninvasive background-free mapping of pathological events with improved sensitivity, enhanced specificity, and multiplexed capabilities remains a major challenge. Here, we introduce paramagnetic glyconanofluorides as small-sized (<10 nm) glycomimetics for immunotargeting and sensitive noninvasive in vivo19F magnetic resonance imaging (MRI) mapping of inflammation. A very short T1 relaxation time (70 ms) of the fluorides was achieved by doping the nanofluorides' solid crystal core with paramagnetic Sm3+, resulting in a significant 8-fold enhancement in their 19F MRI sensitivity, allowing faster acquisition and improved detectability levels. The fabricated nanosized glycomimetics exhibit significantly enhanced uptake within activated immune cells, providing background-free in vivo mapping of inflammatory activity, demonstrated in both locally induced inflammation and clinically related neuropathology animal models. Fabricating two types of nanofluorides, each with a distinct chemical shift, allowed us to exploit the color-like features of 19F MRI to map, in real time, immune specificity and preferred targetability of the paramagnetic glyconanofluorides, demonstrating the approach's potential extension to noninvasive multitarget imaging scenarios that are not yet applicable for nanobiomimetics based on other nanocrystal cores.

Engineering Carbohydrate-Based Particles for Biomedical Applications: Strategies to Construct and Modify

Carbohydrate-based micro/nanoparticles have gained significant attention for various biomedical applications such as targeted/triggered/controlled drug delivery, bioimaging, biosensing, etc., because of their prominent characteristics like biocompatibility, biodegradability, hydrophilicity, and nontoxicity as well as nonimmunogenicity. Most importantly, the ability of the nanoparticles to recognize specific cell sites by targeting cell surface receptors makes them a promising candidate for designing a targeted drug delivery system. These particles may either comprise polysaccharides/glycopolymers or be integrated with various polymeric/inorganic nanoparticles such as gold, silver, silica, iron, etc., to reduce the toxicity of the inorganic nanoparticles and thus facilitate their cellular insertion. Various synthetic methods have been developed to fabricate carbohydrate-based or carbohydrate-conjugated inorganic/polymeric nanoparticles. In this review, we have highlighted the recently developed synthetic approaches to afford carbohydrate-based particles along with their significance in various biomedical applications.

Synthesis of biocompatible silver nanoparticles by a modified polyol method for theranostic applications: Studies on red blood cells, internalization ability and antibacterial activity

Recently, there has been ongoing research in the field of nanotechnology and nanomedicine aiming at developing multifunctional biomaterials using noble metals. The unique properties of silver (Ag) are known from ancient times and thus are being explored for their behavior on the nano scale. Silver shows high antimicrobial activity against different microorganisms, while modification of the surface of its nanostructures can be useful in active targeting regarding cancer treatment. During the synthetic procedure, in order to obtain a more uniform sample of silver nanoparticles (Ag NPs) with spherical morphology, a stabilizer is essential. The stabilizers used not only control the progression of the reaction, but also increases the biocompatibility of the NPs. Thus, we managed to synthesize spherical and rod-like Ag NPs via a polyol method and stabilize them with polyvinylpyrrolidone (PVP). The resulted Ag NPs were characterized morphologically with Transmission Electron Microscopy (TEM) and further confirmed by their structural characterization (FT-IR, UV-Vis, Dynamic Light Scattering (DLS) and Zeta Potential). For their biocompatibility profile, we studied their interaction with red blood cells (RBCs) through hemolysis assay and we monitored their structural alterations through SEM. The antimicrobial activity was tested with the agar diffusion disc assay for Gram negative and Gram positive microorganisms E. coli and S. aureus respectively. Nanoparticles' (NPs) internalization and localization studies in cancer cells were monitored with fluorescence microscopy in MCF-7 and U87-MG. According to our results it is worth it to investigate the potential of these nanomaterials since they can have a significant role in applications of theranostics in nanomedicine.

TRAIL-conjugated silver nanoparticles sensitize glioblastoma cells to TRAIL by regulating CHK1 in the DNA repair pathway

OBJECTIVES

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively triggers apoptosis in cancer cells, but not in normal cells. Resistance of glioblastoma cells to TRAIL is a major obstacle for successful clinical treatment of TRAIL. Thus, there is an essential requirement for novel approaches to sensitize TRAIL resistance. Silver nanoparticles (AgNPs) are one of the most promising nanomaterials that show immense antitumor potential via targeting various cellular and molecular processes; however, the effects of AgNPs on TRAIL sensitivity in cancer cells remain unclear. Therefore, we hypothesized that TRAIL-conjugated AgNPs (TRAIL-AgNPs) can overcome TRAIL resistance through inducing death receptor activation in glioblastoma cells, but not normal cells.

METHODS

In this study, the therapeutic effect of TRAIL-AgNPs is investigated by analyzing the cell viability, caspase activity, and CHK1 gene expression in T98 G TRAIL-Sensitive (TS) and T98 G TRAIL-Resistant (TR) glioblastoma cells.

RESULTS

It is found that TRAIL-AgNPs are more toxic compared to TRAIL and AgNPs treatments alone on TR cells. While TRAIL and AgNPs alone do not enhance the caspase activity, conjugation of TRAIL to AgNPs increases the caspase activity in TR cells. Moreover, the TRAIL-AgNPs-treated TR cells show less CHK1 expression compared to the TRAIL treatment.

CONCLUSION

These results suggest that TRAIL sensitivity of TR cells can be enhanced by conjugation of TRAIL with AgNPs, which would be a novel therapeutic approach to sensitize TRAIL resistance.

Non-cytotoxic, temperature-responsive and antibacterial POEGMA based nanocomposite coatings with silver nanoparticles

Non-cytotoxic, temperature-responsive and antibacterial poly(di(ethylene glycol)methyl ether methacrylate) - POEGMA188 based nanocomposite coatings attached to a glass surface were successfully prepared using ATRP polymerization. The thickness, morphology and wettability of the resulting coatings were analyzed using ellipsometry, AFM and contact angle measurements, respectively. The strong impact of the thicknesses of the POEGMA188 grafted brush coatings and content of AgNPs on the morphology and temperature-induced wettability changes of the nanocomposite was demonstrated. In addition to the strong temperature-dependent antibacterial activity, the proposed nanocomposite coatings have no significant cytotoxic effect towards normal cells. Moreover, the slight anti-cancer effect of AgNPs may be suggested.

Controlled release of silver ions from AgNPs using a hydrogel based on konjac glucomannan and chitosan for infected wounds

Konjac glucomannan is a biocompatible polysaccharide with high medicinal potential. In this study, we prepared a hydrogel using an optimized crosslinking konjac glucomannan and chitosan. Silver nanoparticles (AgNPs) were incorporated into the hydrogel to enhance its antimicrobial property. This nanocomposite hydrogel could absorb wound exudates due to its swelling ability, and showed self-healing property that enabled structure stability. Moreover, as a carrier, the hydrogel could modulate the release of silver ions burst, thereby reducing AgNPs cytotoxicity. Rats models with infected skin defects were used to assess wound healing. The results indicated that AgNPs hydrogels dressing could promote wound healing and reduce inflammatory response, exhibiting great clinical application potentials.

Size-dependent cellular uptake and localization profiles of silver nanoparticles

Purpose: Silver nanoparticles (AgNPs) have been widely applied in various fields as excellent antibacterial reagents over the past decades. Although the particle size is considered as the most crucial factor influencing cellular uptake, transportation, and accumulation behaviors, there are still many controversies regarding the correlation between size and uptake of AgNPs. In this study, size-dependent cellular uptake of AgNPs with different diameters was investigated in B16 cells. Methods: The uptake of AgNPs was investigated by inductively coupled plasma-mass spectrometry (ICP-MS) and transmission electron microscopic (TEM) imaging in B16 cells. Results: Twenty nanometer and 100 nm AgNPs had the lowest and highest uptake efficiency at both 12 hours and 24 hours, respectively. Smaller AgNPs crossed the plasma membrane faster with uniform distribution: 5 nm AgNPs were detected in both cytoplasm and nucleus at 0.5 hours after incubation. Larger AgNPs were extremely difficult to migrate: 100 nm AgNPs were detected in the nucleus at 12 hours after incubation. Internalization of AgNPs was directly observed, mainly within membrane-bound structures, such as intracellular vesicles and late endosomes. The uptake of all four-sized AgNPs (5 nm, 20 nm, 50 nm, 100 nm) decreased significantly after the pre-treatment with chlorpromazine hydrochloride, which can specifically inhibit the clathrin-mediated endocytosis. The internalization efficiencies of AgNPs (5 nm, 20 nm, 50 nm) were markedly reduced by methyl-β-cyclodextrin, a specific caveolin-mediated endocytosis inhibitor, whereas 5-(N-ethyl-N-isopropyl) amiloride as an inhibitor of macropinocytosis inhibited the uptake of larger sizes of AgNPs (50 nm and 100 nm). Conclusion: The results suggest that the size of AgNPs can not only affect the efficiency of cellular uptake, but also the type of endocytosis. The clathrin-mediated endocytosis may be the most common endocytic pathway for AgNPs in B16 cells, and AgNPs at each size were likely to enter cells by a major internalization pathway.

"Command" surfaces with thermo-switchable antibacterial activity

In the presented work "smart" antibacterial surfaces based on silver nanoparticles (AgNPs) embedded in temperature-responsive poly(di(ethylene glycol)methyl ether methacrylate) - (POEGMA188) as well as poly(4-vinylpyridine) - (P4VP) coatings attached to a glass surface were successfully prepared. The composition, thickness, morphology and wettability of the resulting coatings were analyzed using ToF-SIMS, XPS, EDX, ellipsometry, AFM, SEM and CA measurements, respectively. Temperature-switched killing of the bacteria was tested against Escherichia coli ATCC 25922 (representative of Gram-negative bacteria) and Staphylococcus aureus ATCC 25923 (representative of Gram-positive bacteria) at 4 and 37 °C. In general at 4 °C no significant difference was observed between the amounts of bacteria accounted on the grafted brush coatings and within the control sample. In contrast, at 37 °C almost no bacteria were visible for temperature-responsive coating with AgNPs, whereas the growth of bacteria remains not disturbed for "pure" coating, indicating strong temperature-dependent antibacterial properties of AgNPs integrated into brushes.

Functional Studies of Anodic Oxidized β-Ti-28Nb-11Ta-8Zr Alloy for Mechanical, In-vitro and Antibacterial Capability

We developed an osseocompatible β-type Ti-28Nb-11Ta-8Zr (TNTZ) alloy that displays the excellent elastic modulus, cellular response, corrosion resistance and antibacterial capability demanded for bone-mimetic materials. The TNTZ alloy exhibited an elastic modulus of 49 GPa, which approximates that of human bones and prevent stress shielding effects. A further anodic oxidation and subsequent post-annealing modification formed a crystalline nanoporous TNTZ oxide layer (NPTNTZO(c)) on the alloy surface, potentially promoting interlocking with the extracellular matrix of bone cells and cell proliferation. Osteoblast viability tests also verified that NPTNTZO(c) enhanced cell growth more significantly than that of flat TNTZ. In addition, potentiodynamic polarization tests in Hanks' balanced salt solution (HBSS) revealed that both TNTZ and NPTNTZO(c) exhibited better corrosion resistance than commercial pure titanium. Finally, NPTNTZO(c) reinforced with silver nanoparticles (NPTNTZO

Exploiting in vitro potential and characterization of surface modified Zinc oxide nanoparticles of Isodon rugosus extract: Their clinical potential towards HepG2 cell line and human pathogenic bacteria

Little is known about biogenically synthesized Zinc oxide nanoparticles (ZnONPs) from Isodon rugosus. Synthesis of metal oxide NPs from essential oil producing medicinal plants results in less harmful side effects to the human population as compared to chemically synthesized NPs. In this article, we report biogenic synthesis of ZnONPs from in vitro derived plantlets and thidiazuron (TDZ) induced callus culture of Isodon rugosus. Synthesized NPs were characterized using UV-spectra, XRD, FTIR, SEM and EDX. Furthermore, the NPs were evaluated for their potential cytotoxic (against HepG2 cell line) and antimicrobial (against drug resistant Staphylococcus epidermidis, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa) activities. Pure crystalline ZnONPs with hexagonal and triangular shapes were obtained as a result of callus extract (CE) and whole plant extract (WPE), respectively. ZnONPs showed potent cytotoxic and antimicrobial potential. The antimicrobial and cytotoxic activities of ZnONPs were found to be shape and surface bound phytochemicals dependent. CE mediated hexagonal ZnONPs showed superior anti-cancer and antimicrobial activities as compared to WPE mediated triangular shaped ZnONPs. It is concluded that biogenic ZnONPs have incredible potential as theranostic agents and can be adopted as useful drug delivery system in next generation treatment strategies.

Shining Light on Chitosan: A Review on the Usage of Chitosan for Photonics and Nanomaterials Research

Chitosan (CS) is a natural polymer derived from chitin that has found its usage both in research and commercial applications due to its unique solubility and chemical and biological attributes. The biocompatibility and biodegradability of CS have helped researchers identify its utility in the delivery of therapeutic agents, tissue engineering, wound healing, and more. Industrial applications include cosmetic and personal care products, wastewater treatment, and corrosion protection, to name a few. Many researchers have published numerous reviews outlining the physical and chemical properties of CS, as well as its use for many of the above-mentioned applications. Recently, the cationic polyelectrolyte nature of CS was found to be advantageous for stabilizing fascinating photonic materials including plasmonic nanoparticles (e.g., gold and silver), semiconductor nanoparticles (e.g., zinc oxide, cadmium sulfide), fluorescent organic dyes (e.g., fluorescein isothiocyanate (FITC)), luminescent transitional and lanthanide complexes (e.g., Au(I) and Ru(II), and Eu(III)). These photonic systems have been extensively investigated for their usage in antimicrobial, wound healing, diagnostics, sensing, and imaging applications. Highlighted in this review are the different works involving some of the above-mentioned molecular-nano systems that are prepared or stabilized using the CS polymer. The advantages and the role of the CS for synthesizing and stabilizing the above-mentioned optically active materials have been illustrated.

Efficacy of green nanoparticles against cancerous and normal cell lines: a systematic review and meta-analysis

This study aimed to perform a systematic review and meta-analysis of papers discussing the efficacy of microbial synthesised metallic nanoparticles (MNPs) against cancerous and normal cell lines by exploiting Bayesian generalised linear (BGL) model. Data was systematically collected from published papers via Cochrane library, Web of Science, PubMed, Science Direct, ProQuest, Scopus, and Embase. Impressively, most of the studies were carried out on HeLa and A549 cancer cell lines. Specifically, a hefty 65.67% of studies employed bacteria to biofabricate MNPs. Significantly, BGL meta-analysis represented highly valuable information. Hence, based on adjusted analysis, the MNPs with the size of 25-50 nm were found to be far less cytotoxic than the MNPs with the size of ≤25 nm (OR = 0.233, P ˂ 0.05) against either cancerous or normal cell lines. Interestingly, it was found that the odds of cytotoxicity in cancerous cell lines were practically nine times more than normal cell lines, representing the substantially more cytotoxicity of MNPs in cancerous cell lines (OR = 9.004, P ˂ 0.001). Green MNPs mentioned here may be developed as novel anti-cancer agents, which could lead to a revolution in the treatment of cancer.

Contradictory effects of silver nanoparticles on activated sludge wastewater treatment

Increased amount of nano-silver will be released into domestic and industrial waste streams due to its extensive application. However, great controversy still exists on the effects of silver nanoparticle (Ag-NP) on biological wastewater treatment processes and a toxicology model has not been built yet. Four sequencing batch reactors with activated sludge has been run for over three months with different silver species at a concentration of 1mg Ag/L in influent. Both freshly prepared Ag-NPs and aged Ag-NPs were tested with released silver ion as control. Results in this study showed that Ag-NPs, especially freshly prepared Ag-NPs, can help to maintain or even increase the diversity of microbial community in activated sludge and the biomass concentration even under long-term treatment. It indicates that the hormesis model need to be considered for the toxicology of Ag-NPs.

DNA-dependent protein kinase modulates the anti-cancer properties of silver nanoparticles in human cancer cells

Silver nanoparticles (Ag-np) were reported to be toxic to eukaryotic cells. These potentially detrimental effects of Ag-np can be advantageous in experimental therapeutics. They are currently being employed to enhance the therapeutic efficacy of cancer drugs. In this study, we demonstrate that Ag-np treatment trigger the activation of DNA-PKcs and JNK pathway at selected doses, presumably as a physiologic response to DNA damage and repair in normal and malignant cells. Ag-np altered the telomere dynamics by disrupting the shelterin complex located at the telomeres and telomere lengths. The genotoxic effect of Ag-np was not restricted to telomeres but the entire genome as Ag-np induced γ-H2AX foci formation, an indicator of global DNA damage. Inhibition of DNA-PKcs activity sensitised the cancer cells towards the cytotoxicity of Ag-np and substantiated the damaging effect of Ag-np at telomeres in human cancer cells. Abrogation of JNK mediated DNA repair and extensive damage of telomeres led to greater cell death following Ag-np treatment in DNA-PKcs inhibited cancer cells. Collectively, this study suggests that improved anti-proliferative and cytotoxic effects of Ag-np treatment in cancer cells can be achieved by the inhibition of DNA-PKcs.

Evaluation of oxidative stress induction in rats following exposure to silver nanorods

The study investigated the oxidative stress induction by the 10 and 25 nm silver nanorods (SNRs) following intra-tracheal instillation in rats after 1 day, 1 week, 1 month and 3 months post instillation periods at 1 and 5 mg/kg b.w. doses. The blood was withdrawn by retro orbital plexus method after exposure periods and different oxidative stress markers were estimated. The results showed that the both sizes of SNRs induced increased levels of malondialdehyde (MDA) and depleted glutathione (GSH) levels after 1 day and 1 week post exposure periods. The 10 and 25 nm SNRs at both doses displayed that significantly reduced levels of superoxide dismutase (SOD) and catalase following 1 day and 1 week post exposure periods. Also, the results have shown that decrease in total antioxidant capacity (TAC) of both sizes of SNRs significantly following 1 day and 1 week post exposure periods, indicating the oxidative stress induction by SNRs. In spite, there were no significant changes in oxidative stress markers following 1 month and 3 months post exposure periods may be due to recovery. The increased levels of MDA and decreased levels of GSH, SOD, catalase and TAC activity are strongly associated to ROS production and lipid peroxidation, suggesting the induction of oxidative stress in rats. The 10 nm SNRs at 5 mg/kg b.w. dose exposures in rats have shown greater changes in all oxidative stress parameters, indicating the greater induction of oxidative stress when compared with the 25 nm SNRs, representing the size-dose-dependent induction of oxidative stress of SNRs.

Antibacterial effects of titanium embedded with silver nanoparticles based on electron-transfer-induced reactive oxygen species

Although titanium embedded with silver nanoparticles (Ag-NPs@Ti) are suitable for biomedical implants because of the good cytocompatibility and antibacterial characteristics, the exact antibacterial mechanism is not well understood. In the present work, the antibacterial mechanisms of Ag-NPs@Ti prepared by plasma immersion ion implantation (PIII) are explored in details. The antibacterial effects of the Ag-NPs depend on the conductivity of the substrate revealing the importance of electron transfer in the antibacterial process. In addition, electron transfer between the Ag-NPs and titanium substrate produces bursts of reactive oxygen species (ROS) in both the bacteria cells and culture medium. ROS leads to bacteria death by inducing intracellular oxidation, membrane potential variation, and cellular contents release and the antibacterial ability of Ag-NPs@Ti is inhibited appreciably after adding ROS scavengers. Even though ROS signals are detected from osteoblasts cultured on Ag-NPs@Ti, the cell compatibility is not impaired. This electron-transfer-based antibacterial process which produces ROS provides insights into the design of biomaterials with both antibacterial properties and cytocompatibility.

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.

In Vitro and In Vivo Toxicity Evaluation of Colloidal Silver Nanoparticles Used in Endodontic Treatments

INTRODUCTION

Silver nanoparticles have been used for different purposes in dentistry, including endodontic treatments. The aim of this study was to determine the cytotoxicity of different types of silver nanoparticles on mouse fibroblast cell line L929 and the reaction of subcutaneous connective tissue of Wistar rats to these nanoparticles.

METHODS

Silver nanoparticles of an average size of 5 nm were synthesized with ammonia (SNA) or polyvinylpyrrolidone (SNP). L929 was exposed to SNA and SNP (0.1-100 μg/mL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and enzyme-linked immunosorbent assays were performed after 6, 24, and 48 hours. Culture medium was used as the control. Sixteen rats received, individually, 3 polyethylene tubes filled with a fibrin sponge embedded in 100 μL SNA or SNP (1 μg/mL). A fibrin sponge with no embedding was the control. Tissue reaction was performed qualitatively and quantitatively after 7, 15, 30, and 90 days of implantation in the dorsal connective tissue of Wistar rats.

RESULTS

SNA and SNP were cytotoxic to L929 in higher concentrations, with SNA significantly more toxic than SNP. SNA and SNP did not induce significant interleukin-1β and interleukin-6 production. The release of stem cell factor by L929 increased 48 hours after the treatment with SNP at 5 μg/mL. Histologic examination showed that the inflammatory responses caused by SNA and SNP at 1 μg/mL were similar to the control in all experimental periods.

CONCLUSIONS

It was concluded that SNA and SNP were not cytotoxic at 25 μg/mL or lower concentrations. However, for safe clinical use, further studies establishing others points of its toxicologic profile are recommended.

The Combination of Laser Therapy and Metal Nanoparticles in Cancer Treatment Originated From Epithelial Tissues: A Literature Review

Several methods have been employed for cancer treatment including surgery, chemotherapy and radiation therapy. Today, recent advances in medical science and development of new technologies, have led to the introduction of new methods such as hormone therapy, Photodynamic therapy (PDT), treatments using nanoparticles and eventually combinations of lasers and nanoparticles. The unique features of LASERs such as photo-thermal properties and the particular characteristics of nanoparticles, given their extremely small size, may provide an interesting combined therapeutic effect. The purpose of this study was to review the simultaneous application of lasers and metal nanoparticles for the treatment of cancers with epithelial origin. A comprehensive search in electronic sources including PubMed, Google Scholar and Science Direct was carried out between 2000 and 2013. Among the initial 400 articles, 250 articles applied nanoparticles and lasers in combination, in which more than 50 articles covered the treatment of cancer with epithelial origin. In the future, the combination of laser and nanoparticles may be used as a new or an alternative method for cancer therapy or diagnosis. Obviously, to exclude the effect of laser's wavelength and nanoparticle's properties more animal studies and clinical trials are required as a lack of perfect studies.

Lactose-modified DNA tile nanostructures as drug carriers

BACKGROUND

DNA hybridization allows the preparation of nanoscale DNA structures with desired shape and size. DNA structures using simple base pairing can be used for the delivery of drug molecules into the cells. Since DNA carries multiple negative charges, their cellular uptake efficiency is low. Thus, the modification of the DNA structures with molecules that may enhance the cellular internalization may be an option.

OBJECTIVE

The objective of this study is to construct DNA-based nanocarrier system and to investigate the cellular uptake of DNA tile with/without lactose modification.

METHODS

Doxorubicin was intercalated to DNA tile and cellular uptake of drug-loaded DNA-based carrier with/without lactose modification was investigated in vitro. HeLa, BT-474, and MDA-MB-231 cancer cells were used for cellular uptake studies and cytotoxicity assays. Using fluorescence spectroscopy, flow cytometry, and confocal microscopy, cellular uptake behavior of DNA tile was investigated. The cytotoxicity of DNA tile structures was determined with WST-1 assay.

RESULTS

The results show that modification with lactose effectively increases the intracellular uptake of doxorubicin loaded DNA tile structure by cancer cells compared with the unmodified DNA tile.

CONCLUSION

The findings of this study suggest that DNA-based nanostructures modified with carbohydrates can be used as suitable multifunctional nanocarriers with simple chemical modifications.

Glucose-functionalized Au nanoprisms for optoacoustic imaging and near-infrared photothermal therapy

Targeted imaging and tumor therapy using nanomaterials has stimulated research interest recently, but the high cytotoxicity and low cellular uptake of nanomaterials limit their bioapplication. In this paper, glucose (Glc) was chosen to functionalize Au nanoprisms (NPrs) for improving the cytotoxicity and cellular uptake of Au@PEG-Glc NPrs into cancer cells. Glucose is a primary source of energy at the cellular level and at cellular membranes for cell recognition. A coating of glucose facilitates the accumulation of Au@PEG-Glc NPrs in a tumor region much more than Au@PEG NPrs. Due to the high accumulation and excellent photoabsorbing property of Au@PEG-Glc NPrs, enhanced optoacoustic imaging of a tumor in vivo was achieved, and visualization of the tumor further guided cancer treatment. Based on the optical-thermal conversion performance of Au@PEG-Glc NPrs, the tumor in vivo was effectively cured through photothermal therapy. The current work demonstrates the great potential of Au@PEG-Glc NPrs in optoacoustic imaging and photothermal cancer therapy in future.

Peptides conjugated to silver nanoparticles in biomedicine – a “value-added” phenomenon

This review presents a glimpse of the various aspects of nanoparticles, in particular silver nanoparticles and their conjugation to peptides, thus opening an avenue for new discoveries in nanomaterials.

Silver nanoparticles disrupt regulation of steroidogenesis in fish ovarian cells

Despite the influx of silver nanoparticles (nAg) into the marine environment, their effects on fish reproduction remain completely unexplored. Using ovarian primary cells from marine medaka (Oryzias melastigma), in vitro studies were carried out to evaluate the effects of two differently coated nAg particles (Oleic Acid, (OA) nAg and Polyvinylpyrrolidone, (PVP) nAg) on fish ovarian tissues, using AgNO3 as a positive control. Cytotoxicity was evaluated by MTT assay and expression of key genes regulating steroidogenesis (StAR, CYP 19a, CYP 11a, 3βHSD and 20βHSD) were determined by Q-RT-PCR. EC50 values for PVP nAg, OA nAg and AgNO3 were 7.25μgL(-1), 924.4μgL(-1), and 42.0μgL(-1) respectively, showing that toxicity of silver was greatly enhanced in the PVP coated nano-form. Down regulation of CYP 19a was observed in both nAg and AgNO3 treatments, while down regulation of 3βHSD was only found in the OA nAg and AgNO3 treatments. For the first time, our results demonstrated that nAg can affect specific genes regulating steroidogenesis, implicating nAg as a potential endocrine disruptor.

Novel Mn3 [Co(CN)6]2@SiO2@Ag Core-Shell Nanocube: Enhanced Two-Photon Fluorescence and Magnetic Resonance Dual-Modal Imaging-Guided Photothermal and Chemo-therapy

The versatile Mn3[Co(CN)6]2@SiO2@Ag core-shell NCs are prepared by a simple coprecipitation method. Ag nanoparticles with an average diameter of 12 nm deposited on the surface of Mn3[Co(CN)6]2@SiO2 through S-Ag bonding are fabricated in ethanol solution by reducing silver nitrate (AgNO3 ) with NaBH4 . The NCs possess T1 -T2 dual-modal magnetic resonance imaging ability. The inner Prussian blue analogs (PBAs) Mn3[Co(CN)6]2 exhibit bright two-photon fluorescence (TPF) imaging when excited at 730 nm. Moreover, the TPF imaging intensity displays 1.85-fold enhancement after loading of Ag nanoparticles. Besides, the sample also has multicolor fluorescence imaging ability under 403, 488, and 543 nm single photon excitation. The as-synthesized Mn3[Co(CN)6]2@SiO2@Ag NCs show a DOX loading capacity of 600 mg g(-1) and exhibit an excellent ability of near-infrared (NIR)-responsive drug release and photothermal therapy (PTT) which is induced from the relative high absorbance in NIR region. The combined chemotherapy and PTT against cancer cells in vitro test shows high therapeutic efficiency. The multimodal treatment and imaging could lead to this material a potential multifunctional system for biomedical diagnosis and therapy.

Carbohydrate polymer inspired silver nanoparticles for filaricidal and mosquitocidal activities: A comprehensive view

The carbohydrate polymer inspired silver nanoparticles (AgNPs) are designed and synthesized through ultrasound assisted green process using unique combination of a biomolecule (tyrosine) and a natural polymer (starch). A comprehensive mechanistic study on the reactive oxygen species (ROS) mediated filaricidal (against Setaria cervi) and mosquitocidal (against second and fourth instar larvae of Culex quinquefasciatus) activities of AgNPs has been made for the first time for controlling filariasis by taking care of both filariid and its vector. The mechanism may help in formulating antifilarial drug based on carbohydrate polymer inspired AgNPs. The role of carbohydrate polymer in inspiring bioactivity of AgNPs has been looked into and its activities have been compared with the commercially available AgNPs. Cytotoxicity of AgNPs on macrophages of Wistar rat has been evaluated to ensure its selectivity towards filariid and larvae.

Gene Expression, Protein Function and Pathways of Arabidopsis thaliana Responding to Silver Nanoparticles in Comparison to Silver Ions, Cold, Salt, Drought, and Heat

Silver nanoparticles (AgNPs) have been widely used in industry due to their unique physical and chemical properties. However, AgNPs have caused environmental concerns. To understand the risks of AgNPs, Arabidopsis microarray data for AgNP, Ag⁺, cold, salt, heat and drought stresses were analyzed. Up- and down-regulated genes of more than two-fold expression change were compared, while the encoded proteins of shared and unique genes between stresses were subjected to differential enrichment analyses. AgNPs affected the fewest genes (575) in the Arabidopsis genome, followed by Ag⁺ (1010), heat (1374), drought (1435), salt (4133) and cold (6536). More genes were up-regulated than down-regulated in AgNPs and Ag⁺ (438 and 780, respectively) while cold down-regulated the most genes (4022). Responses to AgNPs were more similar to those of Ag⁺ (464 shared genes), cold (202), and salt (163) than to drought (50) or heat (30); the genes in the first four stresses were enriched with 32 PFAM domains and 44 InterPro protein classes. Moreover, 111 genes were unique in AgNPs and they were enriched in three biological functions: response to fungal infection, anion transport, and cell wall/plasma membrane related. Despite shared similarity to Ag⁺, cold and salt stresses, AgNPs are a new stressor to Arabidopsis.

In vitro studies of the toxic effects of silver nanoparticles on HeLa and U937 cells

In the last decade, much attention has been paid to studies of the effect of silver nanoparticles (Ag NPs) on tumor cells. Apart from elucidation of the mechanism of NPs' interaction with mammalian cells, these studies are aimed at discovering new effective antitumor drugs. In this work, we report about the toxic effects of Ag NPs observed on two types of tumor cells: HeLa (adhesive cells) and U937 (suspension cells). The Ag NPs were obtained by an original method of biochemical synthesis. Particle size was 13.2±4.72 nm, and zeta potential was -61.9±3.2 mV. The toxicity of Ag NPs in the concentration range 0.5-8.0 μg Ag/mL was determined by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cytofluorometry after 4 and 24 hours' incubation. It was found that Ag NPs had high toxicity toward both cell types. The minimal concentrations where a toxicity effect was registered (toxicity thresholds) lied in the range 0.5-2.0 μg Ag/mL. In parallel with the Ag NP solution, cells were incubated with water solutions of the NP stabilizer (aerosol-OT) and Ag(+) ions (as silver nitrate). It was shown that aerosol-OT had no effect on the viability on HeLa cells, but was moderately toxic toward U937, though less dangerous for these cells than Ag NPs. With Ag(+) ions, for HeLa no toxic effect was observed, while for U937 they were as toxic as the Ag NPs. The data obtained indicate that Ag NPs as used in this study may prove to be useful for the creation of medicines for cancer therapy.

In vitro 30 nm silver nanoparticles promote chondrogenesis of human mesenchymal stem cells

Silver nanoparticles positively influence chondrogenesis of human mesenchymal stem cells through promoting expression of chondrogenic markers while reducing hypertrophy.