Photon Cross Correlation Spectroscopy Research Articles

Silver Nanoparticles Produced In Vitro by Berberis vulgaris Fruit and Their Antioxidant, Antimicrobial and Ex Ovo Irritation Potential Study

Green synthesis was successfully used for silver nanoparticles (Ag NPs) preparation using Berberis vulgaris aqueous extracts. The ultraviolet and visible (UV–Vis) spectroscopy, photon cross-correlation spectroscopy (PCCS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) techniques were used for characterization of the Ag NPs and confirmed the presence of Ag(0) in nanoparticles. The bimodal morphology was discovered, namely, the larger particles had elongated shape and size around 200 nm, while the smaller ones were spherical with a size of up to ten microns. All the nanoparticles (NPs) showed antioxidant activity against radical DPPH and ferric-reducing antioxidant power. The Ag NPs possess antibacterial effects against Escherichia coli and Staphylococcus aureus comparable to silver nitrate solution. In addition, also irritation potential of the produced Ag NPs has been investigated ex Ovo and no irritation of vessels and their surroundings was found, which shows the harmless character of the products.

Insights into emulsion synthesis of self-assembled suprastructures formed by Janus silica particles with -NH2/-SH surface groups.

Spherical particles with tunable anisotropic structures enabled by multiple surface functionalities have garnered interest for their potential applications in adsorption technologies. The presence of diverse functional groups in the surface layer, exhibiting varying acidity and hydrophilicity, can lead to unique characteristics in terms of surface structure and behaviour. In this study, the particles were synthesised using a two-step approach involving surface functionalisation of previously synthesised SiO2 Stöber particles. This was achieved by employing 3-mercaptopropyltrimethoxysilane (MPTMS) and 3-aminopropyltrimethoxysilane (APTMS) in a toluene-in-water emulsion. The resulting particles were found to be nonporous, with a specific surface area of 8 m2 g-1. Their sizes were determined to be up to 350 nm through photon cross-correlation spectroscopy. Moreover, the particles exhibited a high net content of functional groups (both amino and mercapto) of 2 mmol g-1. The organisation of the particles during synthesis was observed through SEM images, providing insights into their structural characteristics. Additionally, the study of Eu(iii), Au(iii), and Ag(i) ions and fluorescein adsorption demonstrated varying interactions on the surface, highlighting the potential applications and versatility of these functionalised particles.

Antimicrobial activity of phytofabricated silver nanoparticles using Carica papaya L. against Gram-negative bacteria.

Antibiotic resistance, especially in Gram-negative bacteria, is a major public health risk affecting all industries requiring the use of antibiotics, including agriculture and animal breeding. This study aimed to use papaya extracts to synthesize silver nanoparticles (AgNPs) and evaluate their antimicrobial activity against various Gram-negative bacteria. Silver nanoparticles were synthesized from the aqueous extracts of papaya seed, root, and bark, with AgNO3 used as a reducing agent. The phytofabricated AgNPs were analyzed by ultraviolet-visible absorbance, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and photon cross-correlation spectroscopy (PCCS). The disc-diffusion method was used to perform antibacterial analysis, and the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations were determined. We also investigated the antibiofilm activity of AgNPs and attempted to elucidate the potential mechanism of action on Escherichia coli ATCC 25922. Phytofabrication of AgNPs was successful with papaya root (PR-AgNPs) and papaya seed (PS-AgNPs), but not with papaya bark. Silver nanoparticles using papaya root and PS-AgNPs were both cubic and showed maximum absorbances of 2.6 and 0.3 AUs at 411.6 and 416.8 nm wavelengths and average hydrodynamic diameters X50 of 59.46 ± 7.03 and 66.57 ± 8.89 nm, respectively. The Ag in both AgNPs was confirmed by X-ray fluorescence by a distinctive peak in the spectrum at the silver Kα line of 22.105 keV. Both AgNPs exhibited broad-spectrum antimicrobial and antibiofilm activity against all Gram-negative bacteria, and PR-AgNPs were slightly better than AgNPs-PS. The MIC ranged from 16 μg/mL-128 μg/mL and 16 μg/mL-64 μg/mL, respectively, for PS-AgNPs and PR-AgNPs. The elucidation of the mechanism of action revealed interference with E. coli ATCC 25922 growth kinetics and inhibition of H+-ATPase proton pumps. Papaya seed and root extracts were efficient reducing agents for the biogenic synthesis of AgNPs, with noteworthy antibacterial and antibiofilm activities. Future studies should be conducted to identify the phytochemicals and the mechanism involved in AgNPs synthesis.

Antifungal activity of silver nanoparticles prepared using Aloe vera extract against Candida albicans.

Resistance to antifungal agents is a serious public health concern that has not been investigated enough because most studies on antimicrobials are dedicated to antibacterial resistance. This study aimed to synthesize silver nanoparticles (AgNPs) using Aloe vera extract, and to assess its antifungal activity against Candida albicans. Silver nanoparticles were synthesized by reducing Ag nitrate with aqueous A. vera extracts. Physicochemical properties of synthesized AgNPs were determined by ultraviolet-visible spectrophotometry, photon cross-correlation spectroscopy, energy-dispersive X-ray fluorescence spectrometry, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy. An antifungal investigation was performed against four clinical C. albicans (C1, C2, C3, and C4) and a reference strain, C. albicans ATCC 10321. Cubic AgNPs with a mean X50 hydrodynamic diameter of 80.31 ± 10.03 nm were successfully synthesized. These AgNPs exhibited maximum absorbance at 429.83 nm, and X-ray fluorescence (XRF) confirmed the presence of Ag in AgNPs solution by a characteristic peak in the spectrum at the Ag Kα line of 22.105 keV. Infrared spectra for AgNPs and A. vera extract indicated that the compounds present in the extract play an essential role in the coating/capping of synthesized AgNPs. Different concentrations (200, 100, 50, 25, 10, and 5 μg/mL) of AgNPs were tested. The antifungal activity was shown to be dose-dependent with inhibition zones ranging from 10 mm to 22 mm against C. albicans ATCC 10231, 0 mm to 15 mm against C1, 0 mm to 16 mm against C2 and C3, and 0 mm to 14 mm for C4. Minimum inhibitory concentration ranged from 16 μg/mL to 32 μg/mL against clinical C. albicans (C1, C2, C3, and C4) and was 4 μg/mL against C. albicans ATCC 10231. This study showed the ability of A. vera to serve as an efficient reducing agent for the biogenic synthesis of AgNPs with excellent antifungal activity.

Laser Intensity of Thermo-Responsive Nanoparticles Size Measurement Using Dynamic Light Scattering

Dynamic light scattering (DLS) or photon cross-correlation spectroscopy (PCCS) is a very potent means for analyzing the diffusion behaviour of supramolecules in their solution form. The diffusion coefficient, probed from the scattered light by supramolecules underexposure to incident light, allows the hydrodynamic radii to be calculated. However, the scattering values were recently misled by an unexpected interaction between the incident light and thermo-sensitive nanogels. Hence, in turn, it resulted in a miscalculation of the size of the nanogels by more than 100% of their expected values. The study fulfills a vital knowledge gap by investigating the effects of laser intensity on the size of thermo-sensitive Poly(N-Isopropyl Acrylamide-Vinyl Pyrrolidone-Polyethylene Glycol Diacrylate-(2-(Dimethyl Amino)Ethyl Methacrylate)), Poly(NIPAAM-PVP-PEGDA-DMAEMA) nanogels and subsequent count rates in DLS measurements. The Lower Critical Solution Temperature, LCST phase transition of Poly(NIPAAM-PVP-PEGDA-DMAEMA) nanogel can be observed using the DLS technique. The higher laser intensity was advantageous for measuring at high dilution more vigorously with varying laser intensities. Thus, a sufficient laser intensity should be chosen based on the light scattering characteristics of typical samples.

Optimization of Ethanolic Extraction of Enantia chloranta Bark, Phytochemical Composition, Green Synthesis of Silver Nanoparticles, and Antimicrobial Activity

In this study, using the Box–Behnken model, we optimized the ethanolic extraction of phytochemicals from Enantia chloranta bark for the first time, assessed the composition with HPLC-MS/MS, performed the green synthesis of silver nanoparticles (AgNPs) and characterized them with UV-Vis spectrophotometry, photon cross-correlation spectroscopy, energy-dispersive X-ray fluorescence spectrometry, and Fourier transform infrared spectroscopy. The antibacterial and antibiotic-resistance reversal properties of optimized extract (O-ECB) and AgNPs were assessed on various microorganisms (15 Gram−, 7 Gram+, and 2 fungi) using the well diffusion method and microbroth dilution assay. The mechanism of action was investigated on growth kinetic and proton pumps of Escherichia coli. The in vivo antimicrobial activity and toxicity were assessed on Galleria mellonella larvae. The optimal mass yield (14.3%) related to the highest antibacterial activity (31 mm vs. S. aureus ATCC 6538) was obtained with the following operating conditions: % EtOH—100%; ratio m/v—20 g/mL; and extraction time—6 h. All the compounds identified in O-ECB were alkaloids and the major constituents were palmatine (51.63%), columbamine +7,8-dihydro-8-hydroxypalmatine (19.21%), jatrorrhizine (11.02%), and pseudocolumbamine (6.33%). Among the minerals found in O-ECB (S, Si, Cl, K, Ca, Mn, Fe, Zn, and Br), Br, Fe, and Cl were the most abundant with mean fluorescence intensities of 4.6529, 3.485,4, and 2.5942 cps/uA, respectively. The synthesized AgNPs revealed a strong absorption plasmon band between 430 and 450 nm and an average hydrodynamic diameter ×50 of 59.74 nm, and the presence of Ag was confirmed by a characteristic peak in the spectrum at the silver Kα line of 22.105 keV. Both O-ECB and AgNPs displayed noteworthy and broad-spectrum antimicrobial activities against 20/24 and 24/24 studied microorganisms, respectively, with recorded minimal inhibitory concentrations (MICs) ranging from 8 to ≥1024 µg/mL and 2 to 64 µg/mL. O-ECB and AgNPs showed antibiofilm properties and significantly enhanced the efficacy of conventional antibiotics against selected multidrug-resistant bacteria, and the mechanistic investigations revealed their interference with bacterial growth kinetic and the inhibition of H+-ATPase proton pumps. LD50s were 40 mg/mL and 0.6 mg/mL for O-ECB and AgNPs, respectively. In conclusion, the current study provides a strong experimental baseline to consider Enantia chlorantha bark and their green synthetized AgNPs as potent antimicrobial compounds in this era of antimicrobial resistance.

Mechanochemical Preparation, Characterization and Biological Activity of Stable CuS Nanosuspension Capped by Bovine Serum Albumin.

The biocompatible nanosuspension of CuS nanoparticles (NPs) using bovine serum albumin (BSA) as a capping agent was prepared using a two-stage mechanochemical approach. CuS NPs were firstly synthetized by a high-energy planetary ball milling in 15 min by milling elemental precursors. The stability of nanoparticles in the simulated body fluids was studied, revealing zero copper concentration in the leachates, except simulated lung fluid (SLF, 0.015%) and simulated gastric fluid (SGF, 0.078%). Albumin sorption on CuS NPs was studied in static and dynamic modes showing a higher kinetic rate for the dynamic mode. The equilibrium state of adsorption was reached after 90 min with an adsorption capacity of 86 mg/g compared to the static mode when the capacity 59 mg/g was reached after 2 h. Then, a wet stirred media milling in a solution of BSA was introduced to yield the CuS-BSA nanosuspension, being stable for more than 10 months, as confirmed by photon cross-correlation spectroscopy. The fluorescent properties of the nanosuspension were confirmed by photoluminescence spectroscopy, which also showed that tryptophan present in the BSA could be closer to the binding site of CuS than the tyrosine residue. The biological activity was determined by in vitro tests on selected cancer and non-tumor cell lines. The results have shown that the CuS-BSA nanosuspension inhibits the metabolic activity of the cells as well as decreases their viability upon photothermal ablation.

Antibacterial activity and characteristics of silver nanoparticles biosynthesized from Carduus crispus

In recent years’ synthesis of metal nanoparticle using plants has been extensively studied and recognized as a non-toxic and efficient method applicable in biomedical field. The aim of this study is to investigate the role of different parts of medical plant Carduus crispus on synthesizing silver nanoparticles and characterize the produced nanoparticle. Our study showed that silver nanoparticles (AgNP) synthesized via whole plant extract exhibited a blue shift in absorption spectra with increased optical density, which correlates to a high yield and small size. Also, the results of zeta potential, X-ray diffraction, photon cross-correlation spectroscopy analysis showed the surface charge of − 54.29 ± 4.96 mV (AgNP-S), − 42.64 ± 3.762 mV (AgNP-F), − 46.02 ± 4.17 mV (AgNP-W), the crystallite size of 36 nm (AgNP-S), 13 nm (AgNP-F), 14 nm (AgNP-W) with face-centered cubic structure and average grain sizes of 145.1 nm, 22.5 nm and 99.6 nm. Another important characteristic, such as elemental composition and constituent capping agent has been determined by energy-dispersive X-ray spectroscopy and Fourier transform infrared. The silver nanoparticles were composed of ~ 80% Ag, ~ 15% K, and ~ 7.5% Ca (or ~ 2.8% P) elements. Moreover, the results of the FTIR measurement suggested that the distinct functional groups present in both AgNP-S and AgNP-F were found in AgNP-W. The atomic force microscopy analysis revealed that AgNP-S, AgNP-F and AgNP-W had sizes of 131 nm, 33 nm and 70 nm respectively. In addition, the biosynthesized silver nanoparticles were evaluated for their cytotoxicity and antibacterial activity. At 17 µg/ml concentration, AgNP-S, AgNP-F and AgNP-W showed very low toxicity on HepG2 cell line but also high antibacterial activity. The silver nanoparticles showed antibacterial activity on both gram-negative bacterium Escherichia coli (5.5 ± 0.2 mm to 6.5 ± 0.3 mm) and gram-positive bacterium Micrococcus luteus (7 ± 0.4 mm to 7.7 ± 0.5 mm). Our study is meaningful as a first observation indicating the possibility of using special plant organs to control the characteristics of nanoparticles.

Facile Biogenic Synthesis and Characterization of Seven Metal-Based Nanoparticles Conjugated with Phytochemical Bioactives Using Fragaria ananassa Leaf Extract.

In this investigation, for the first time, we used Fragaria ananassa (strawberry) leaf extract as a source of natural reducing, capping or stabilizing agents to develop an eco-friendly, cost-effective and safe process for the biosynthesis of metal-based nanoparticles including silver, copper, iron, zinc and magnesium oxide. Calcinated and non-calcinated zinc oxide nanoparticles also synthesized during a method different from our previous study. To confirm the successful formation of nanoparticles, different characterization techniques applied. UV-Vis spectroscopy, X-ray Diffraction (XRD) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Photon Cross-Correlation Spectroscopy (PCCS) and Fourier Transformed Infrared Spectroscopy (FT-IR) were used to study the unique structure and properties of biosynthesized nanoparticles. The results show the successful formation of metal-based particles in the range of nanometer, confirmed by different characterization techniques. Finally, the presented approach has been demonstrated to be effective in the biosynthesis of metal and metal oxide nanoparticles.

Antibacterial activity of grapefruit peel extracts and green-synthesized silver nanoparticles.

Background and Aim:The gradual loss of efficacy of conventional antibiotics is a global issue. Plant material extracts and green-synthesized nanoparticles are among the most promising options to address this problem. Therefore, the aim of this study was to assess the antibacterial properties of aqueous and hydroalcoholic extracts of grapefruit peels as well as their inclusion in green-synthesized silver nanoparticles (AgNPs).Materials and Methods:Aqueous and hydroalcoholic extracts (80% v/v) were prepared, and the volume and mass yields were determined. The synthesis of AgNPs was done in an eco-friendly manner using AgNO3 as a precursor. The nanoparticles were characterized by ultraviolet–vis spectrometry and photon cross-correlation spectroscopy. The antibacterial activity of the extracts was tested on three Gram-positive bacteria (Staphylococcus aureus ATCC 6538, clinical Enterococcus faecalis, and S. aureus) and two Gram-negative bacteria (two clinical Escherichia coli) using various concentrations of extracts (100, 50, 25, 12, and 5 mg/mL and 5% dimethyl sulfoxide as negative control). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the microdilution method. Modulation of cefazoline and ampicillin on resistant E. coli and S. aureus strains was added to the mixture design response surface methodology with extreme vertices design, with the diameters of inhibition and the fractional inhibitory concentration index as responses and factors, respectively. The antibiotic, the ethanolic extract, and water varied from 0.1 MIC to 0.9 MIC for the first two and from 0 to 0.8 in proportion for the third. Validating the models was done by calculating the absolute average deviation, bias factor, and accuracy factor.Results:The volume yield of the EE and aqueous extract (AE) was 96.2% and 93.8% (v/v), respectively, whereas their mass yields were 7.84% and 9.41% (m/m), respectively. The synthesized AgNPs were very uniform and homogeneous, and their size was dependent on the concentration of AgNO3. The antibacterial activity of the two extracts was dose-dependent, and the largest inhibition diameter was observed for the Gram-positive bacteria (S. aureus ATCC 6538; AE, 12; EE, 16), whereas AgNPs had a greater effect on Gram-negative bacteria. The MICs (mg/mL) of the AEs varied from 3.125 (S. aureus ATCC 6538) to 12.5 (E. coli 1 and E. coli 2), whereas the MICs of the EEs varied from 1.5625 (S. aureus 1, S. aureus ATCC 6538, and E. faecalis) to 6.25 (E. coli 1). There was a significant difference between the MICs of AEs and EEs (p=0.014). The MBCs (mg/mL) of the AEs varied from 12.5 (S. aureus ATCC 6538) to 50 (S. aureus 1), whereas those of the EEs varied from 6.25 (S. aureus 1) to 25 (E. coli 1 and E. faecalis). Ethanolic grapefruit extracts demonstrated an ability to modulate cefazolin on E. coli and S. aureus but were completely indifferent to ampicillin on E. coli.Conclusion:Grapefruit peel extracts and their AgNPs exhibit antibacterial properties that can be exploited for the synthesis of new antimicrobials and their EEs may be efficiently used synergistically with other antibiotics against bacteria with intermediate susceptibility.

Green Synthesis of Silver Nanoparticles with Antibacterial Activity Using Various Medicinal Plant Extracts: Morphology and Antibacterial Efficacy.

A green synthetic route for the production of silver nanoparticles (AgNPs) using five different aqueous plant extracts, namely, Berberis vulgaris, Brassica nigra, Capsella bursa-pastoris, Lavandula angustifolia and Origanum vulgare, was investigated in this study. The present work demonstrates the influence of plant extract composition (antioxidant and total phenolic content) on the size and morphology of the produced AgNPs. The biosynthetic procedure was rapid and simple and was easily monitored via colour changes and ultraviolet and visible (UV-Vis) spectroscopy. Subsequently, measurement of zeta potential (ZP), photon cross-correlation spectroscopy (PCCS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) analysis were employed to characterise the as-synthesised nanoparticles. The XRD investigation confirmed the presence of Ag0 in the nanoparticles, and interactions between the bioactive compounds of the plants and the produced AgNPs were evident in the FTIR spectra. TEM indicated that the nanoparticles exhibited a bimodal size distribution, with the smaller particles being spherical and the larger having a truncated octahedron shape. In addition, the antimicrobial activity of the AgNPs was tested against five bacterial strains. All synthesised nanoparticles exhibited enhanced antimicrobial activity at a precursor concentration of 5 mM compared to the control substance, gentamicin sulphate, with the best results observed for AgNPs prepared with B. nigra and L. angustifolia extracts.

Thermosensitive Drug Delivery System SBA-15-PEI for Controlled Release of Nonsteroidal Anti-Inflammatory Drug Diclofenac Sodium Salt: A Comparative Study.

Mesoporous SBA-15 silica material was prepared by the sol–gel method and functionalized with thermosensitive polyethylenimine polymers with different molecular weight (g·mol−1): 800 (SBA-15(C)-800), 1300 (SBA-15(C)-1300) and 2000 (SBA-15(C)-2000). The nonsteroidal anti-inflammatory drug (NSAID) diclofenac sodium was selected as a model drug and encapsulated into the pores of prepared supports. Materials were characterized by the combination of infrared spectroscopy (IR), atomic force microscopy (AFM), transmission electron microscopy (TEM), photon cross-correlation spectroscopy (PCCS), nitrogen adsorption/desorption analysis, thermogravimetry (TG), differential scanning calorimetry (DSC) and small-angle X-ray diffraction (SA-XRD) experiments. The drug release from prepared matrixes was realized in two model media differing in pH, namely small intestine environment/simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2), and at different temperatures, namely normal body temperature (T = 37 °C) and inflammatory temperature (T = 42 °C). The process of drug loading into the pores of prepared materials from the diclofenac sodium salt solutions with different concentrations and subsequent quantitative determination of released drugs was analyzed by UV-VIS spectroscopy. Analysis of prepared SBA-15 materials modified with polyethylenimines in solution showed a high ability to store large amounts of the drug, up to 230 wt.%. Experimental results showed their high drug release into the solution at pH = 7.4 for both temperatures, which is related to the high solubility of diclofenac sodium in a slightly alkaline environment. At pH = 2, a difference in drug release rate was observed between both temperatures. Indeed, at a higher temperature, the release rates and the amount of released drug were 2–3 times higher than those observed at a lower temperature. Different kinetic models were used to fit the obtained drug release data to determine the drug release rate and its release mechanism. Moreover, the drug release properties of prepared compounds were compared to a commercially available medicament under the same experimental conditions.

Effect of High-Energy Vibrating Ball Milling in the Reduction of the Crystallite Size of TiO<sub>2</sub> Particles

In this work, TiO2 powders were prepared by high energy vibrating ball milling. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Photon cross correlation spectroscopy (PCCS with Nanophox) were used to determine the crystallite size of anatase TiO2. Depending on the grinding conditions (short grinding time, ball diameter, stainless steel ball and grinding powder ratio), the crystallite size decreased from 34 nm to 8 nm. The average diameter of a TiO2 particle with 8 nm crystals was ~221 nm. No structural phase transition was observed during milling.

Study on physical properties of dispersed silica

The paper deals with the physical properties of colloidal silica dispersed system such as distribution width (Qx, %) and density (qx, %) defined by photon cross correlation spectroscopy (PCCS) at an average size of 17.06 nm for D50 % and the area of specific surface of 349.96 m2 cm−3 depending on molar (Rm2) optimal ratio of silica stone mineral to alkali ash powder. The change of crystal structure to amorphous state was determined by X-ray diffraction analysis. The results of their kinematic viscosity, liquid density, UV light adsorption inspections show possibility to produce the colloidal silica by using the wetting and ultrasonic vibration method for that fusible alloy.

Nonconvex Morphology of Metallic Copper Obtained via Nonclassical Crystallization of Copper Hydride

Copper particles with a desert rose morphology and high surface area were obtained via decomposition of a copper hydride whose particles possesses a similar shape. Copper hydride was synthesized by the reaction between copper sulfate and hypophosphorous acid at 50 °C. The different reaction steps of the copper hydride formation were monitored by two time-dependent techniques: in situ photon cross-correlation spectroscopy and ex -situ transmission electron microscopy. At the initial stage of the reaction, emulsion droplets of a particular size were formed, followed by the growth and agglomeration of copper hydride crystallites in the confinement of these droplets. The final structure consists of rose-like shaped particles with an average size of about 217 ± 53 nm arranged into chains. The surface area of these particles was estimated to be 41 ± 8 m2/g. The nucleation and growth of the copper hydride occur via a nonclassical crystallization pathway.

Porous Silicon as a Nanomaterial for Disperse Transport Systems of Targeted Drug Delivery to the Inner Ear

The samples of porous silicon (por-Si) particles in three size ranges (60–80, 250–300, and 500–600 nm) are obtained by electrochemical anodic etching of single-crystal silicon in an electrolyte based on an HF solution, followed by a change in the modes of ultrasonic treatment and homogenization. A complex characterization of particles was carried out by scanning electron microscopy, photon cross-correlation spectroscopy, and X-ray photoelectron spectroscopy. In vitro biocompatibility models using unicellular organisms of infusoria Paramecium caudatum Keln are applied to demonstrate the low toxicity of the samples at concentrations used for intravenous administration. The systemic in vivo biodistribution was studied for the por-Si 60–80 nm sample using adult Wistar rats. Introduced nanoobjects are found in the liver and heart tissues without significant changes in shape or size and predominantly in the oxidized state. Possibilities of using por-Si samples as matrices for transporting pharmaceuticals with intravenous administration are studied by assessing the intensity of the ototropic effect of gentamicin. An objective audiologic method for studying the amplitude of otoacoustic emission revealed the largest otodepressive effect of gentamicin when submicrometer-sized por-Si particles (500–600 nm) was used as a disperse system for drug delivery. Thus, modifications of the conditions for the synthesis of por-Si nanoparticles are promising directions in obtaining physicochemical parameters of transport particles that are optimal for specific tasks of targeted drug delivery.

Calcium-dependent cyto- and genotoxicity of nickel metal and nickel oxide nanoparticles in human lung cells

BackgroundGenotoxicity is an important toxicological endpoint due to the link to diseases such as cancer. Therefore, an increased understanding regarding genotoxicity and underlying mechanisms is needed for assessing the risk with exposure to nanoparticles (NPs). The aim of this study was to perform an in-depth investigation regarding the genotoxicity of well-characterized Ni and NiO NPs in human bronchial epithelial BEAS-2B cells and to discern possible mechanisms. Comparisons were made with NiCl2 in order to elucidate effects of ionic Ni.MethodsBEAS-2B cells were exposed to Ni and NiO NPs, as well as NiCl2, and uptake and cellular dose were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS). The NPs were characterized in terms of surface composition (X-ray photoelectron spectroscopy), agglomeration (photon cross correlation spectroscopy) and nickel release in cell medium (ICP-MS). Cell death (necrosis/apoptosis) was investigated by Annexin V-FITC/PI staining and genotoxicity by cytokinesis-block micronucleus (cytome) assay (OECD 487), chromosomal aberration (OECD 473) and comet assay. The involvement of intracellular reactive oxygen species (ROS) and calcium was explored using the fluorescent probes, DCFH-DA and Fluo-4.ResultsNPs were efficiently taken up by the BEAS-2B cells. In contrast, no or minor uptake was observed for ionic Ni from NiCl2. Despite differences in uptake, all exposures (NiO, Ni NPs and NiCl2) caused chromosomal damage. Furthermore, NiO NPs were most potent in causing DNA strand breaks and generating intracellular ROS. An increase in intracellular calcium was observed and modulation of intracellular calcium by using inhibitors and chelators clearly prevented the chromosomal damage. Chelation of iron also protected against induced damage, particularly for NiO and NiCl2.ConclusionsThis study has revealed chromosomal damage by Ni and NiO NPs as well as Ni ionic species and provides novel evidence for a calcium-dependent mechanism of cyto- and genotoxicity.

Reduction of 2,4-Dinitrophenol to 2,4-Diaminophenol Using AuNPs and AgNPs as Catalyst

In this study, colloidal metal nanoparticles have been prepared by the wet-chemical synthesis method. Gold and silver nanoparticles with approximate sphere shape were synthesized through the citrate-reduction method. The colloidal metal nanoparticles were characterized by using UV-vis absorption spectroscopy, photon cross-correlation spectroscopy (PCCS) and transmission electron microscope (TEM). Catalytic activities of the metal nanoparticles were investigated through reduction of 2,4-dinitrophenol to 2,4-diaminophenol in the presence of NaBH4 at room temperature. Both gold and silver nanoparticles showed an excellent catalytic activity.

Synthesis and sorption properties of bridged polysilsesquioxane microparticles containing 3-mercaptopropyl groups in the surface layer

In this paper the technique of obtaining mercapto-containing spherical particles based on 1,2-bis(triethoxysilyl)ethane (BTESE) and 3-mercaptopropyltrimethoxysilane (MPTMS) using the modified Stöber method was developed. The hydrolytic polycondensation reaction of alkoxysilanes was carried out in ethanol solution and catalyzed by fluoride ions. The influence of various factors (ratio of reacting components, the amount of solvent and water) on the morphology, particle size, porosity, and content of SH-groups was studied.The synthesized materials were investigated by scanning electron microscopy, photon cross-correlation spectroscopy, Fourier-transform infrared and Raman spectroscopies, X-ray photoelectron spectroscopy, N2 adsorption–desorption isotherms, elemental analysis. Using these methods, it was determined that such silica particles feature mesoporous spheres of about ∼250–300nm in size with 3.4-7.3mmol/g of sulfur-containing groups, both thiol and disulfide. The effects of the contact time and the initial concentrations of Ag(I), Pb(II), and Cd(II) ions were analyzed by conventional static mode adsorption test. The obtained materials remove metal ions from the wastewater.

Bifunctional silica nanospheres with 3-aminopropyl and phenyl groups. Synthesis approach and prospects of their applications

Spherical silica particles with bifunctional (Si(CH2)3NH2/SiC6H5) surface layers were synthesized by the Stöber method using ternary alkoxysilanes systems. The influence of the synthesis conditions, such as temperature and stirring time on the process of nanoparticles formation was studied. The presence of introduced functional groups was confirmed by FTIR. The composition of the surface layers examined by elemental analysis and acid-base titration was shown to be independent from the synthesis temperature. However, the size of the obtained particles depends on the synthesis temperature and, according to photon cross-correlation spectroscopy, can be varied from 50 to 846nm. The variation of electric charges of N-functional groups was disclosed in obtained nanospheres and attributed to different surface location of these groups and their surrounding with other groups. The sorption of Cu(II) ions by functionalized silicas depends on the concentration of amino groups, which correlates with the isoelectric point values (determined to vary from 8.26 to 9.21). Bifunctional nanoparticles adsorb 99.0mg/g of methylene blue, compared with 48.0mg/g by silica sample with only amino groups. The nanospheres, both with and without adsorbed Cu2+, demonstrate reasonable antibacterial activity against S. aureus ATCC 25923, depending on particle concentration in water suspension.