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New types of biological apatites have been discovered in molar sheep and horse teeth and are divided in two types. In the first and more general type, the release of Mg ions is parallel to the changes in composition of apatite leading to a final stoichiometric ratio of Ca to P ions, going from dentin depth towards the boundary of enamel with air. Inside dentin, another apatite sub-types were discovered with alternating layers of Mg-rich and C-rich apatites. The approximate formal stoichiometric relationships for these peculiar types of bioapatites are suggested. We identified two kinds of ion-exchanges responsible for formation of peculiar apatites. Various combinations of main and minor elements lead to new versions of biological apatites.

The use of natural surfactants including plant extracts, plant hydrocolloids and proteins in nanoemulsion systems has received commercial interest due to demonstrated safety of use and potential health benefits of plant products. In this study, a whey protein isolate (WPI) from a byproduct of cheese production was used to stabilize a nanoemulsion formulation that contained hempseed oil and the Aesculus hippocastanum L. extract (AHE). A Box–Behnken experimental design was used to set the formulation criteria and the optimal nanoemulsion conditions, used subsequently in follow-up experiments that measured specifically emulsion droplet size distribution, stability tests and visual quality. Regression analysis showed that the concentration of HSO and the interaction between HSO and the WPI were the most significant factors affecting the emulsion polydispersity index and droplet size (nm) (p &lt, 0.05). Rheological tests, Fourier transform infrared spectroscopy (FTIR) analysis and L*a*b* color parameters were also taken to characterize the physicochemical properties of the emulsions. Emulsion systems with a higher concentration of the AHE had a potential metabolic activity up to 84% in a microbiological assay. It can be concluded from our results that the nanoemulsion system described herein is a safe and stable formulation with potential biological activity and health benefits that complement its use in the food industry.

Plant-based protein sources have a characteristic aroma that limits their usage in various meat-alternative formulations. Despite being the most popular plant-based protein, the allergenicity of soy protein severely restricts the potential adoption of soy protein as an animal substitute. Thereby, allergen-free plant-protein sources need to be characterized. Herein, we demonstrate a rapid solid-phase-microextraction gas-chromatography/mass-spectrometry (SPME-GC/MS) technique for comparing the volatile aroma profile concentration of two different allergen-free plant-protein sources (brown rice and pea) and comparing them with soy protein. The extraction procedure consisted of making a 1:7 w/v aqueous plant protein slurry, and then absorbing the volatile compounds on an SPME fibre under agitation for 10 min at 40 °C, which was subsequently injected onto a GC column coupled to an MS system. Observed volatile concentrations were used in conjunction with odour threshold values to generate a Total Volatile Aroma Score for each protein sample. A total of 76 volatile compounds were identified. Aldehydes and furans were determined to be the most dominant volatiles present in the plant proteins. Both brown rice protein and pea protein contained 64% aldehydes and 18% furans, with minor contents of alcohols, ketones and other compounds. On the other hand, soy protein consisted of fewer aldehydes (46%), but a more significant proportion of furans (42%). However, in terms of total concentration, brown rice protein contained the highest intensity and number of volatile compounds. Based on the calculated odour activity values of the detected compounds, our study concludes that pea proteins could be used as a suitable alternative to soy proteins in applications for allergen-free vegan protein products without interfering with the taste or flavour of the product.

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.

To meet the growing interest in natural antibacterial agents, we evaluated the physicochemical and biological properties of the folk medicine known as “five thieves’ oil” (Polish name: olejek pięciu złodziei). Five thieves’ oil consists of a mixture of five oils: rosemary, lemon, clove, eucalyptus, and cinnamon. In this study, we performed gas chromatography, FTIR, and UV–vis spectroscopic analysis, as well as L-a-b color tests, contact angle determination, and surface tension determination. To verify its antibacterial activity, the metabolic activity and changes in cell membrane permeability of bacteria of the genus Pseudomonas were studied. As a result, it was found that among the constituent oils, the oils of clove and cinnamon were the least volatile and, at the same time, had the strongest antibacterial activity. However, a mix of all the oils also showed comparable activity, which was even more pronounced for the oils after 4 weeks of aging. This effect can be linked to the high content of terpene derivatives such as eugenol and cinnamaldehyde, which can cause changes in bacterial membrane permeability, affecting cell activity and survival. This study is the first to characterize the constituents of the popular folk medicine five thieves’ oil, confirming and explaining its strong antibacterial activity, thus constituting a significant contribution to contemporary health education.

Dynamic light scattering (DLS) is one of the most commonly used for rapid particle size determination. The advantages of DLS for fast and simple colloid systems (i.e. food, emulsions) and nanoparticles dispersion characterization is limited due to particle shape and possible interactions between the sample and the measuring solution. In this paper, we present the results of monodispersed polystyrene standardized nanobeads, silver and polydispersed submicron-sized fluorinated particles (HFBMA) and silica synthesized by a modified Stober method. We compared the obtained results in “standard conditions” with non-standard situations, such as using tap water or employing Ringer solution as a dispersant. Furthermore, the studies were performed at both room temperature (20 °C) and elevated temperature (37 °C) to simulate various possible applications of nanosystem investigations in the biomedical field. The results show that sample behaviours might not only vary with temperature and dispersant changes, but may also fluctuate during the time of measurement (i.e. aggregation process could be observed). Presented results will open discussion about factors other than dilution and concentrations for observing behavior of the nanoparticles and submicron particles in “real conditions”. Our studies confirmed the hypothesis that more than one particle size determination technique is recommended. Moreover, particle size verification is recommended during long-term storage and when environmental conditions change.

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.

α-Tocopherol oxalate (TO), a tocopherol ester derivative, was investigated for its effect on the structural changes of fully hydrated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) liposomes, as a function of concentration and temperature, by applying differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), and DPH fluorescence anisotropy methods. The DSC and DPH anisotropy data indicated that TO embedded into DPPC membrane lowered the enthalpy (ΔHm) and temperature (Tm) of the main phase transition as well its cooperativity. Fluidization of the membrane at a lowered temperature was accompanied by formation of mixed structures of tocopherol-enriched domains. SAXS studies showed the formation of various ordered structures in DPPC gel-phase during incorporation of TO into the bilayer, as evidenced by the existence of lamellar phases with repeat distances (d) of 6.13 and 6.87 nm, assigned to TO-enriched domains and a lamellar, liquid-ordered DPPC phase with d = 8.45 nm at increasing TO concentrations with lowering and broadening of the Bragg peaks, and diffuse scattering, characteristic of a fluid Lα phase, were observed. In DPPC fluid-phase, the increasing presence of TO at low concentrations resulted in the appearance of a liquid-ordered phase with repeat d = 6.9 nm coexistent with a lamellar structure with d = 9.2 nm, assigned to liquid-disordered structures. An increasing repeat distance observed with raising the TO amount in the DPPC bilayer evolved from an increasing interlamellar water layer of increasing thickness. Presence of TO facilitated penetration of water molecules into the acyl chain region which decreased van der Waals interactions in the bilayer. The DSC, SAXS, and fluorescence anisotropy data established that TO exhibited pronounced disruptive activity in DPPC membranes compared to α-tocopherol. The driving force of the observed action was attributed to electrostatic and dipole interactions of the acidic moiety with the polar head group of phospholipids in the interface region of the bilayer.

In this paper we present the results of measured physical parameters of self-organized structures consisting of hydrophobic functionalized silver nanoparticles and amphiphilic molecules capable of micelles formation. Those systems may be considered as simple models for transfer of nanoparticles through the biological membrane. Three different surfactants were used: negatively charged sodium dodecyl sulphite, SDS, neutral Triton X-100 and positively charged tetredodecyltrimethyl ammonium bromide, TTABr. We have found that hydrophobic functionalized Ag nanoparticles are encapsulated in neutral Triton X-100 micelles with a diameter of 10 nm without significant change in the size of the micelles. The efficiency of encapsulation of Ag by SDS micelles is lower compared to Triron X-100 and no incorporation of Ag nanoparticles into TTABr occurs. Obtained results indicate that in aqueous environment ionic properties of molecules creating micelles and concentration ratios between components determine the efficiency and kinetics of two competitive processes association or aggregation of nanoparticles and encapsulation of Ag nanoparticles within micelles.

Fluorescent submicron particles of fluorinated methacrylate (HFMBA) with long-term stability have been synthesized and characterized with regard to their potential applications. Rhodamine B (RBITC) isothiocyanate was used as the fluorescent component. The core&ndash, shell structure of the particles effectively protected the dye against bleaching. HFBMA nanoparticle (NP) stability was confirmed after seven years of storage. Only slight differences were found in the polydispersity index (pdi) from 0.002 to 0.010. Particle size measurements were carried out using dynamic light scattering (DLS), nanoparticle tracking (NTA), and fluorescence correlation spectroscopy (FCS). The hydrodynamic diameter evaluated by different methods were in good agreement, respectively: 184&ndash, 550 nm, 218&ndash, 579 nm, and 236&ndash, 508 nm. Particle and core morphology was estimated by using scanning and transmission electron microscopy (SEM and TEM). The ability to recognize particles in 3D as a reference sample in biological media has been confirmed by epifluorescence optical microscopy, confocal laser scanning microscopy, and super-resolution confocal microscopy (STED).

This study describes the formation of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) association colloids (reverse micelles) in rapeseed oil and interactions of sinapic and ferulic acids with these structures. Furthermore, the process of oil autoxidation in the presence of DOPC is characterized and the antioxidant efficiency of phenolic acids in the oil containing reverse micelles is determined. Formation of DOPC reverse micelles above the phospholipid critical micelle concentration (51.13 µmol kg–¹) is observed. The fluorescence probe emission parameters confirm the interactions of sinapic and ferulic acids with reverse micelles and changes of their structure (reduced rigidity) as a result of phenolic acid incorporation. In the analyzed rapeseed oil, an evident prooxidative effect of DOPC reverse micelles is found, as their presence accelerates decomposition of hydroperoxides to hexanal. The antioxidant effect of sinapic acid is strongly influenced by the presence of DOPC reverse micelles. Ferulic acid shows a concentration‐dependent antioxidant effect in relation to the formation of hexanal. Practical Applications: Understanding the influence of sinapic and ferulic acids on the structure of association colloids and rapeseed oil autoxidation in the presence of reverse micelles should facilitate extension of shelf life and reduce oil quality deterioration during storage. This knowledge may also be used to optimize industrial oil refining to provide the desired amount of amphiphilic minor components and native antioxidants. Thus, developed refining using mild conditions or even minimizing the degree of refining is attractive in view of greater retention of health‐promoting compounds in vegetable oil, reduction of processing costs, and increased sustainability of the oil‐refining process.

Three porphyrin dyes were investigated: basic tetraphenylporphyrin (TPP), fluorine tetraphenylporphyrin symmetrically substituted with twelve fluorine atoms (TPPF 12 ) and chlorine tetraphenylporphyrin symmetrically substituted with twelve chlorine atoms (TPP Cl 12 ). TPP without external atoms was used as a standard sample. Photoelectrochemical examinations (short-circuit photocurrent in the second time scale) combined with the spectroscopic methods (absorption, fluorescence, photoacoustics supported by the laser-induced optoacoustic spectroscopy) were applied. On the basis of absorption and fluorescence spectra some spectral parameters were estimated, whereas with photoacoustic methods the thermal parameters and kinetics of thermal relaxation in the microsecond time scale were evaluated. The studies of the dyes in the range from about 10 −6 M up to 10 −3 M show the absence of aggregated structures although dye fluorescence behavior could indicate the presence of weakly interacting dye molecules when the dyes are in their excited states. The results show that the changes in fluorescence behavior indicate redistribution of the electron density in the molecular macroring upon linkage of the fluorine and chlorine atoms to the main molecular core. The results of the photocurrent and spectral examinations were interpreted in terms of occurrence of mesomeric and inductive effects; photocurrent enhancement in the chlorinated porphyrin (TPPCl 12 ) versus the free-based (TPP) and fluorinated (TPPF 12 ) porphyrins support the occurrence of the mesomeric effect which dominates over the inductive one in TPPCl 12 , whereas in TPPF 12 the inductive effect is essential and can lead to photocurrent declining.

Absorption, fluorescence emission, and fluorescence excitation spectra of stilbazolium merocyanine (1-(n-butyl)-4[(3,5-dimethoxy-4-oxocyclohexa-2,5-dienylidene)ethylidene]-1,4-dihydropyridyne) dye in water solution without and with colloidal silver addition were measured. In the presence of the colloid, besides the absorption band assigned to the protonated species of the dye (at 391 nm), an absorption band related to the free-base species appears at 490 nm. From the absorption and emission spectra, measured at various dye concentrations, follows that the aggregates are not effectively formed. Therefore, the long-wavelength absorption and fluorescence bands have to be related to some dye forms created by the solvatochromic effects. The fluorescence bands of the protonated and the free-base species are located at 559 nm and at about 630 nm, respectively. The shape of the long-wavelength band suggests the occurrence of more than one free-base form of the dye. At some dye and colloid concentrations, the global emission of the sample is enhanced as a result of silver addition. The increase in the emission yield of the dye could be partially due to not only the change in the concentrations of dye forms exhibiting various emission yields but is also due to the resonance surface plasmon effect. Because of the superposition of several effects, before the practical application of merocyanine as an indicator of metal presence in biological samples, its spectral properties in the system investigated should be established.

International audience; Thin films containing both the azo-dye disperse red 1 (DR1) and the poly(methylmetacrylate) (PMMA) or the poly(phenylenevinylene) (PPV) are deposited by Langmuir–Blodgett and spin coating techniques on various substrates. The morphology, surface structure and growth pattern of the azo-dye-polymers were studied by atomic force microscopy. Nucleation and growth processes are responsible for the generation of different structures. The spin coated films were additionally oriented using the electric field poling method (corona poling). The film homogeneity is improved by this method in all cases. Due to the polar character of DR1 molecules, rod-like sub-structures are observed after the corona poling process in DR1–MMA films. The indium tin oxide surface enhances reorientation of the azo-dye-polymer molecules during corona poling and results in a significant reduction of the surface roughness.

Changes in the yield of the fluorescence emitted by pigments of photosynthetic organisms could be used for the establishment of the presence of some toxic substances. The presence of colloidal metals can be indicated by enhancement of pigments' emission as a result of plasmons generation. The spectra of the pigments of cyanobacterium Synechocystis located in the bacterium fragments and in solutions with and without colloidal silver additions have been measured. The quantum yield of the pigments' fluorescence in solution has been observed to increase at some wavelength of excitation, while the fluorescence of the pigments in the bacteria fragments has been only quenched as a consequence of interactions with colloidal silver particles. Close contact between pigment molecules located in bacteria fragments and silver particles is probably not possible. We plan in future to investigate the influence of other, more typical metal pollutants of water, using similar spectral methods and several other photosynthetic bacteria pigments, in solution, in cell fragments and in the whole bacteria organisms.

This paper presents the results of spectroscopic investigations on a synthetic dye solution with high fluorescence quantum yield and mixtures of this solution with colloidal silver particles. Basing on the results obtained the influence of the metal nano-particles presence on the changes of intensity and fluorescence quantum yield of the dye was determined. The purpose of the investigation was to determine the usefulness of fluoresceine in the structure of sensors and indicators of metal presence in the environment. The measurements were made for fluoresceine water solutions and its mixtures in the ranges of concentrations from 10 -6 M to 10 -3 M. A significant growth of the fluorescence quantum yield in the presence of colloidal particles was only observed in the range of concentrations from 2•10 -4 M to 8•10 -4 M.