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Fossilized wood belongs to the most exciting, however, rarely studied objects in nature. Several kinds of petrified wood with different combinations of minerals have been studied: apatite – calcite; calcite – pyrite; hematite – gypsum wood; quartz - goethite; goethite – calcite woods, from different countries and estimated as old in the time range of 1.8–306 MA. The samples cover nearly the whole time of tree existence on the Earth. The application of synchrotron radiation for X-ray microdiffraction analysis of petrified wood is presented and compared to elemental (electron microprobe) and molecular (micro Raman) analyses with the use of table-top instruments. The analysis of preserved cells permineralized with two minerals allows tracing both the structure of cell walls and the remains of ancient organic matter. Lignin is most often met among the remains of the primary organic matter and is clearly observed in all kinds of wood, except the apatite-calcite one. The Eh-pH diagrams tailored to each combination of minerals with organic matter allow to estimate the original conditions of mineralization and give the indications for the potential biomimetic synthesis.

There is a high impact of the solar cells on energy manufacturing. For several years the energy efficiency was limited due to base-materials' structural and technological limits. High increase of energy harvesting of solar cells has been observed since the first solar cell based on dye-sensitized colloidal TiO2 films occurred. One of the most promising solutions are used quantum dots (QD) for light energy conversion. In this paper, we described the use of selected characterization techniques for sandwich-type TiO2/QD composites for a low-cost quantum dots' solar cell in the point of view of mass manufacturer of solar cells and research and development laboratory. Moreover, the increasing role of Raman spectroscopy and mapping for the TiO2/QD was presented and compared with other necessity techniques for solar cell investigations such as ellipsometry, atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS).

Nanoemulsion systems receive a significant amount of interest nowadays due to their promising potential in biomedicine and food technology. Using a two-step process, we produced a series of nanoemulsion systems with different concentrations of hemp seed oil (HSO) stabilized with Aesculus hippocastanum L. extract (AHE). Water and commercially-available low-concentrated hyaluronic acid (HA) were used as the liquid phase. Stability tests, including an emulsifying index (EI), and droplet size distribution tests performed by dynamic light scattering (DLS) proved the beneficial impact of AHE on the emulsion&rsquo, s stability. After 7 days of storage, the EI for the water-based system was found to be around 100%, unlike the HA systems. The highest stability was achieved by an emulsion containing 5% HSO and 2 g/L AHE in water, as well as the HA solution. In order to obtain the detailed characteristics of the emulsions, UV-Vis and FTIR spectra were recorded, and the viscosity of the samples was determined. Finally, a visible microscopic analysis was used for the homogeneity evaluation of the samples, and was compared with the DLS results of the water system emulsion, which showed a desirable stability. The presented results demonstrate the possible use of oil emulsions based on a plant extract rich in saponins, such as AHE. Furthermore, it was found that the anti-inflammatory properties of AHE provide opportunities for the development of new emulsion formulations with health benefits.

A new way of electrochemical DNA sensor using as a screening tool for the determination of phytochemicals with high genoprotective functionality is proposed. The biosensor's detection layer was prepared with double stranded deoxyribonucleic acid (ds DNA) that were subjected to oxidative stress induced by •OH radicals generated by Fenton reaction. The oxidized guanine derivative, 8-oxo-7,8-dihydro-2′-deoxyguanosine, was treated as an indicator of DNA oxidative damage. This derivative may cause mutation through its ability to pair with adenine. The abnormalities of DNA structure and DNA repair system are known to be directly related to progressive neurodegeneration. The present study showed that during oxidative stress, the 2.5% oregano extract protected guanine from undergoing oxidation to 8-oxoguanine. The results revealed that this genoprotective effectiveness can make oregano a very efficient protective barrier against oxidative stress. Due to these unique properties of oregano we propose the recipe of a functional bread with its addition. It was found that the functionality of the prepared bread was not limited to antioxidative activity but also is expressed in the inhibition of cholinesterases. These findings indicate that oregano can act as an important component in the therapeutic diet recommended in neurodegenerative disorders.

In this study, two saponins-rich plant extracts, viz. Saponaria officinalis and Quillaja saponaria, were used as surfactants in an oil-in-water (O/W) emulsion based on hempseed oil (HSO). This study focused on a low oil phase content of 2% v/v HSO to investigate stable emulsion systems under minimum oil phase conditions. Emulsion stability was characterized by the emulsification index (EI), centrifugation tests, droplet size distribution as well as microscopic imaging. The smallest droplets recorded by dynamic light scattering (droplets size v. number), one day after the preparation of the emulsion, were around 50&ndash, 120 nm depending the on use of Saponaria and Quillaja as a surfactant and corresponding to critical micelle concentration (CMC) in the range 0&ndash, 2 g/L. The surface and interfacial tension of the emulsion components were studied as well. The effect of emulsions on environmental bacteria strains was also investigated. It was observed that emulsions with Saponaria officinalis extract exhibited slight toxic activity (the cell metabolic activity reduced to 80%), in contrast to Quillaja emulsion, which induced Pseudomonas fluorescens ATCC 17400 growth. The highest-stability samples were those with doubled CMC concentration. The presented results demonstrate a possible use of oil emulsions based on plant extract rich in saponins for the food industry, biomedical and cosmetics applications, and nanoemulsion preparations.

Flowers of Verbascum nigrum L. (mullein) contain considering amounts of saponins which are surfactants with carbohydrates chain in their molecules. Hence, the mullein was used for water-oil (W/O) systems as an emulsion stabilizer. As an oil phase paraffin, rapeseed and Vaseline oils were used respectively. Emulsification and foaming tests were performed to evaluate stability of the emulsion system. Emulsification indexes (EI) were obtained after 24 h of W/O phases mixing. Moreover, EI indexes were determined after 8 weeks (E8w) of emulsions storage at room temperature. The impact of the plant extract particles size was evaluated too. Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) techniques were used for the hydrodynamic diameter (dH) measurements (average values of dH were 133 nm and 92 nm for DLS and NTA analysis respectively). Raman spectra of mullein extracts and zeta potential (ζ = −43.3 mV) were measured and compared with another selected saponins plant extract. The emulsification tests showed that the emulsion stability increased with the decreasing size of the surfactant (mullein) hydrodynamic diameter. The best stability of the investigated O/W emulsion was shown for Vaseline oil system. Moreover, high impact on the surfactant properties of V. nigrum L. has the particle size. The O/W emulsions stabilized by filtrated extract nanoparticles exhibit longer stability than crude extract. The surface properties and nanostructures size proved that mullein extracts can be considered as a potential stabilizer for hydrocolloid systems and dedicated for food industry.

Silica nano- and submicron particles are examples of commonly used nanomaterials with frequently modified surface properties. Various enhanced methods of the fluorescent particles preparations give the opportunities for applications of fluorescent SiO2 as a model system for biomedical interactions between the particles and biostructures such as cells, including beam interactions with materials. Fluorescent core-shell structures were prepared by modified Stober method, where the fluorescent agent was included in the core and then surrounded by a protective shell. As a fluorescent agent Rhodamine-B isothiocyanate was used. The core-shell tunneling size structure was formed by addition of TEOS (tetraethyl orthosilicate) to the base mixture. The size of the particles were investigated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), fluorescence correlation spectroscopy (FCS). Shape and morphology were studied by the transmission and scanning electron microscopy. The fluorescence behavior of the particles was confirmed using NTA in the fluorescent mode and LSM (laser scanning microscope). We confirmed the hydrodynamic diameter in the range between 300 and 1000 nm using the FCS technique. XRD spectra of fluorescent SiO2 were also obtained. This study shows practical aspects of use of selected characterization methods for submicron particle characterization, especially with regard to their fluorescent behavior.

The advent of nanotechnology has increasingly influenced all research fields covering also the food area. The awareness of the peculiar properties of matter at the nanoscale level has stimulated investigations down to submicron (less than 1 μm) and nanosize (1–100 nm). The appealing possibility to evidence interactions among nanostructures in foodstuff is strictly related to both functional and organoleptic properties of food. Besides the most common techniques known well before the advent of nanotechnology, such as light scattering and electron microscopy, Nanoparticle Tracking Analysis (NTA) has come up almost ten years ago. Although the technique is new, the basic principles rely on a well consolidated theoretical knowledge, such as the Stokes-Einstein and the dynamic scattering equations. The aim of this review is to provide an overview of the techniques commonly used to characterize food structures focusing the attention to NTA. Therefore, a literature survey is provided taking into account the many different situations that can occur in food products, spanning from emulsions and protein aggregates to individual nanoparticles, either added to improve food properties or derived from food contamination. A comparison of NTA with the classical dynamic light scattering (DLS) is also included, focusing the attention on the strength and weakness of both techniques. The current increasing interest in NTA is foreseen to expand its use also in food area, by stimulating research in the perspective of a conscious food managing approach.

Copolymers of N -isopropylacrylamide (PNIPAM) are one of the most promising microgel materials for medical applications, especially as a drug carrier. PNIPAMs present unique properties, such as size variation with changing pH and/or temperature. The results of a study on the uptake and release of a dye (Orange II) by microgels of N -isopropylacrylamide copolymer with 1-vinylimidazole (P(NIPAM-co-Vim) are presented. The dye was used as a model low-molecular substance. Hydrodynamic radius ( R h ) of P(NIPAM-co-Vim) particles was measured by dynamic light scattering as a function of temperature in two pH environments: acidic and basic. The dye particles contraction was monitored as a function of temperature at pH 4. The measurements of the zeta potential indicated a positive charge of P(NIPAM-co-Vim) particles at pH 4 and a negative one at pH 9. The key experiments were the internalization and the release of the dye. The effectiveness of this process was measured by UV-Vis spectroscopy on the supernatant derived from centrifuged P(NIPAM-co-Vim) suspension. At room temperature the efficiency of trapping of the dye by the microgel at pH 4 was 87%. Changing pH of a sample initially saturated with the dye from 4 to 9 led to a complete release of the trapped dye.

In this investigation, the fabrication of porous core/shell nanostructures consisting of copper (core) and copper-gold nanoalloy (shell) for medical applications is presented. As a core triangular-shaped copper nanoparticles were used. The porous bimetallic nanoshell was prepared via galvanic reaction in the presence of oil-in water emulsion. It was proved that porous nanoalloy layer can be prepared at pH 7 and in the presence 0.1% and 0.5% oil-in water emulsion. The porous structure fabrication was mainly determined by volume fraction of hexadecane to acetone in the oil-in water emulsion and Zeta-potential of emulsion droplets (pH of emulsion). The influence of emulsion droplets size before galvanic reaction on porous structure preparation was negligible. It was found that doxorubicin could be easily introduced and released from porous core/shell nanostructures, due to spontaneous adsorption on the copper-gold nanoporous surface. The in vitro test showed that cytotoxic effect was more prominent once the doxorubicin was adsorbed on the porous copper-gold nanocarriers. It was demonstrated, that doxorubicin-loaded copper-gold nanostructures caused inhibition cell proliferation and viability of cancer cells, in a concentration-dependent manner. The results indicates that presented coper-gold nanocarrier have potential to be used in targeted cancer therapy, due to its porous structure and cytotoxic effect in cancer cells.

There is a need to develop nanosized and submicron sized stable and efficient fluorescent particles for confocal microscopy and fluorescence correlation spectroscopy, which are useful methods to study dynamics and interactions in complex colloidal systems and living cells. Fluorescent core–transparent shell fluorinated polymer nanoparticles exhibit low refractive index, close to that of water, high fluorescence efficiency, high stability and no cytotoxicity which makes them excellent probes for water based and living systems. Fluorescent core–transparent shell submicron particles were synthesized using 1H,1H-heptafluoro- n -butyl methacrylate (HFBMA) as a monomer and Rhodamine-B-isothiocyanate as a dye. The fluorescent polymeric core was surrounded by a non-fluorescent shell obtained by the seeded growth synthesis. The spherical shape of the particles was confirmed by scanning electron microscopy and the particle size in suspension was characterized by dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS). The effect of different reaction parameters, such as initiator concentration and polymerization time on the particle size and charge density as well as their toxicity were studied. The smallest nanoparticles, of diameter d = 240 nm for the core measured by DLS, were obtained with higher initiator concentration. Repeated confocal imaging, DLS and FCS measurements after a few months up to two years confirmed high fluorescence efficiency, stability and usefulness of prepared particles as versatile systems for confocal microscopy and fluorescence correlation spectroscopy studies in water-based colloidal suspensions. The cytotoxicity tests confirmed a possible use of these nanoparticles also in living cells.

In some applications the dye distribution within fluorescently labeled nanoparticles and its stability over long periods of time are important issues. In this article we study numerically and experimentally the applicability of fluorescence correlation spectroscopy (FCS) to resolve such questions. When the size of fluorescently labeled particles is comparable to or larger than the confocal volume, the effective confocal volume seen in FCS experiments is increasing. Such an effect has already been studied for uniformly labeled spherical particles. In this work we analyze the form of the FCS correlation functions (CFs) for core-labeled and shell-labeled core-shell particles. For shell-labeled particles an additional fast decay was found both in simulations and in experiments on custom-made surface-labeled particles. Universal scaling of FCS correlation times based on the squared ratio of the labeled part radius of gyration to the Gaussian radius of the beam profile was found. Recipes based on the analysis of simulated CFs, proposed for interpretation of experimental results, were successfully applied to the FCS results on suspensions of large core-labeled and surface-labeled particles.

Fluorescent core-shell particles are used as versatile fluorophores in confocal microscopy based image analysis and as a colloidal model system to study short and long-range interactions. Bright and stable microspherical probes are proposed as promising materials, especially in bioimaging applications. The release of dyes from fluorescent polymer microspheres is undesirable. Covalent linking of dyes within polymeric spheres during the polymerization process can solve the problem of dye leaching. This requires, e.g. the introduction of reactive groups into the dyes. Its more lipophilic ester-ether derivatives considerably reduced fluorescence. The fluorescent quantum yield of prepared nanoparticles was determined to be below 10%. As-prepared nanoparticles exhibited a low refractive index (1.293–1.349), hence their use is recommended. Scanning electron microscope (SEM) images and the fluorescence correlation spectroscopy (FCS) measurements confirmed high polydispersity of synthesized particles (40–230 nm), and are in agreement with the dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) results (hydrodynamic diameters 203 ± 9, 548 ± 50, 146 ± 2 nm). The zeta potential of fluorescent 1H,1H-heptafluoro-n-butyl methacrylate (HFBMA) shell nanoparticles (NPs) with propargyl ether-esters, 2-methyl allyl ether-esters and allyl ether-esters of fluorescein was -44.5,-14, -44.7 mV, respectively. The values are different despite the slight difference in the structure of ester-ether derivatives.

The size of nanoparticles is one of the most important factors for their possible applications. Various techniques for the nanoparticle size characterization are available. In this paper selected techniques will be considered base on the prepared core-shell magnetite nanoparticles. Magnetite is one of the most investigated and developed magnetic material. It shows interesting magnetic properties which can be used for biomedical applications, such as drug delivery, hypothermia and also as a contrast agent. To reduce the toxic effects of Fe3O4, magnetic core was covered by dextran and gelatin. Moreover, the shell was doped by fluorescent dye for confocal microscopy investigation. The main investigation focused on the methods for particles size determination of modified magnetite nanoparticles prepared with different techniques. The size distribution were obtained by nanoparticle tracking analysis, dynamic light scattering and transmission electron microscopy. Furthermore, fluorescent correlation spectroscopy (FCS) and confocal microscopy were used to compare the results for particle size determination of core-shell systems.