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Quantitative Description of Isomorphism in the Series of Simple Compounds
The introduction of the notion of energy change resulting from the ion exchange in apatites leads to the question: how can some simple isomorphic series be described using the mentioned idea? We concentrated on the simple isomorphic series of compounds: apatite, bioapatite, calcite, aragonite, celestine, K-, Zn- and Cu-Tutton’s salts. It was demonstrated in all the series, except Tutton’s salts, that the change in energy and the change in the crystal cell volume are, in a simple way, dependent on the change in the ionic radii of the introduced ions. The linear relationships between the variations in energy and in the universal crystallographic dimension d were derived from the earlier equations and proven based on available data. In many cases, except the Tutton’s salts, linear dependence was discovered between the change in energy and the sinus of universal angle Θ, corresponding to the change in momentum transfer. In the same cases, linear dependencies were observed between the energy changes and the changes in the volumes of crystallographic cells, and mutually between changes in the crystallographic cell volume V, crystallographic dimension d, and diffraction angle Θ.
Contribution to Knowledge on Bioapatites: Does Mg Level Reflect the Organic Matter and Water Contents of Enamel?
The matter constituting the enamels of four types of organisms was studied. The variability of the ions was presented in molar units. It was proven that the changes in water contents of the enamel are significantly positively related to changes in Mg; inversely, there is also a strong connection with changes in Ca and P, the main components of bioapatite. The variability in the organic matter has the same strong and positive characteristics and is also coupled with changes in Mg contents. Amelogenins in organic matter, which synthesize enamel rods, likely have a role in adjusting the amount of Mg, thus establishing the amount of organic matter and water in the whole enamel; this adjustment occurs through an unknown mechanism. Ca, P, Mg, and Cl ions, as well as organic matter and water, participate in the main circulation cycle of bioapatites. The selection of variations in the composition of bioapatite occurs only along particular trajectories, where the energy of transformation linearly depends on the following factors: changes in the crystallographic d parameter; the increase in the volume, V, of the crystallographic cell; the momentum transfer, which is indirectly expressed by ΔsinΘ value. To our knowledge, these findings are novel in the literature. The obtained results indicate the different chemical and crystallographic affinities of the enamels of selected animals to the human ones. This is essential when animal bioapatites are transformed into dentistic or medical substitutes for the hard tissues. Moreover, the role of Mg is shown to control the amount of water in the apatite and in detecting organic matter in the enamels.
Steering of Crystal Cell Volumes in Apatites and Bioapatites
The biological variability of apatites in different hard tissues of organisms was the starting point for this investigation. Materials such as whale rostrums, ganoine, and some fish bones were analyzed. It has been proven that different organisms select specific kinds of apatites for the construction of their hard organs at the level of the crystal cell. This probably results from the long-lasting adaptation of the construction to their environmental needs. The materials are characterized by the parameters Δd and ΔE, being the real and apparent deviations from Bragg’s dimension d and the energy of excitation in XRD—E. This study is based on previously published, verified results from a number of researchers and research groups. The derivation of expressions was possible due to an original approach to Bragg’s equation, finally finished in the reformulation of the law, which describes the interplay between the absolute value of the probing excitation energy E and the crystal cell’s internal volume V. It enabled the classification of apatite biomaterials in living and fossil organisms, as well as the classification of the apatite excretions. In addition, the following different possible modes of changes in Bragg’s dimension d were illustrated—spontaneous geometrical expansion, thermal action, pressurization, and single- and multiple-ion exchanges. The contributions of such expansions were estimated. We can steer the cell volume of apatites in various ways. It has been proven that the volume expansion is linearly coupled with the expansion of Bragg’s d parameter in the hexagonal system.
Measurements of Energetic States Resulting from Ion Exchanges in the Isomorphic Crystals of Apatites and Bioapatites
Developments in the field of nanostructures open new ways for designing and manufacturing innovative materials. Here, we focused on new original ways of calculating energy changes during the substitution of foreign ions into the structure of apatites and bioapatites. Using these tools, the energetic costs of ion exchanges were calculated for the exemplary cases known from the literature. It was established that the most costly were ion exchanges of some cations inside apatites and of anions, and the least costly exchanges in tetrad channel positions. Real energy expenses for bioapatites are much smaller in comparison to mineral apatites due to the limited involvement of magnesium and carbonates in the structure of hard tissues. They are of the order of several electron volts per ion. The rigorous dependences of the energy changes and crystallographic cell volumes on the ionic radii of introduced cations were proved. The differentiation of the positioning of foreign ions in locations of Ca(I) and Ca(II) could be calculated in the case of a Ca-Pb reaction in hydroxyapatite. The energetic effects of tooth aging were indicated. The ability of energy change calculation during the ion exchange for isomorphic substances widens the advantages resulting from X-ray diffraction measurements.
The Ways of Forming and the Erosion/Decay/Aging of Bioapatites in the Context of the Reversibility of Apatites
Studies on Chemical Composition, Structure and Potential Applications of Keratoisis Corals
The chemical composition and structure of bamboo octocoral Keratoisis spp. skeletons were investigated by using: Scanning Electron Microscopy SEM, Raman Microscopy, X-ray Diffraction XRD, Laser Ablation–Inductively Coupled Plasma LA-ICP, and amino acid analyzers. Elements discovered in the nodes (mainly organic parts of the skeleton) of bamboo corals showed a very interesting arrangement in the growth ring areas, most probably enabling the application of bamboo corals as palaeochronometers and palaeothermometers. LA-ICP results showed that these gorgonian corals had an unusually large content of bromine, larger than any other organism yet studied. The local concentration of bromine in the organic part of the growth rings of one of the studied corals grew up to 29,000 ppm of bromine. That is over 440 times more than is contained in marine water and 35 times more than Murex contains, the species which was used to make Tyrian purple in ancient times. The organic matter of corals is called gorgonin, the specific substance that both from the XRD and Raman studies seem to be very similar to the reptile and bird keratins and less similar to the mammalian keratins. The missing cross-linking by S-S bridges, absence of aromatic rings, and significant participation of β-turn organization of peptides differs gorgonin from keratins. Perhaps, the gorgonin belongs to the affined but still different substances concerning reptile and bird keratin and in relation to the more advanced version—the mammalian one. Chemical components of bamboo corals seem to have great medical potential, with the internodes as material substituting the hard tissues and the nodes as the components of medicines.
Implications of Isomorphism in the Family of Apatite Compounds
Apatites are very important compounds of mineralogical and biological meaning. Apatites originated from the calcium hydroxy compound 3Ca3(PO4)2·Ca(OH)2 and potentially might form three series of isomorphic salts, derived from cationic substitutions in the positions of Ca(I) and Ca(II) ions in the core compound; anionic substitutions of phosphates; and substitutions of anions and very simple chemical entities instead of the hydroxyl group in channel locations. The energies coupled with the ion exchanges inside those three locations were studied using our original method resulting from the transformation of Braggs’ law. The energy changes resulting from the ion exchanges were studied in connection with either the ionic radii for the cations or ionic volumes for the anions. The same series were observed when the variabilities of energy were confronted with the variabilities in the sinus of diffraction angle Θ showing changes in momentum transfer. In particular, the relationships between the energy changes and the coupled changes in the universal crystallographic parameter d showed the surprising uniformity of all ion exchanges in the apatites. The incremental change in the Braggs’ d-parameter always demands the same change in the energy, with good approximation, independently of the location of the ion exchange. So, the isomorphism of the apatites is not triple but a uniform one at the energy level. Such an approach enables the estimation of the volume of the ion-□ (□-vacancies) agglomerates. The introduction of ions with greater volumes exerts the phenomenon of swelling of apatite cells, which can be quantitatively estimated. The dependence of diffraction spectra on the temperature allows for the determination of minimal values of crystallographic cell volumes and d parameters at the temperature of 0 K. In sum, the study of energies connected with the change of Bragg dimension d is a new and valuable method of insight into the behaviour of apatite crystals.
Strontium coupling with sulphur in mouse bone apatites
Abstract One of the key aspects of new advanced biomaterial development is to understand and design new compositions of selected components. The important idea for bioapatite-based materials is the substitution of Ca by other elements, such as strontium. Here, we evaluated the inorganic part of a network of mouse bone apatite. The effects of administration of Sr into mouse bones do not depend on the form of the supplied compound. Sr addition to mouse bones results in the formation of narrow pipe-like structures including additional sulphates in the periosteum and endosteum and somewhere in the middle of the cortical bone. Sr administration clearly entails meaningful regrouping in the sulphate distribution in bone samples. Supposedly, sulphur is absorbed as the sulphates, and this mechanism resembles the involvement of carbonates. After the consideration of several possible ones, new complicated mechanisms of strontium and sulphate intake into bones were derived, which were not the simple ion-exchanges. Also, an alternate mechanism of attraction of Sr and sulphated glycosaminoglycans was considered. This study is the next step in achieving better knowledge of bioapatite structures and role of additional components, together with their interaction with other elements.
Hierarchy of Bioapatites
Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the development of nanomaterials and nanocompounds. Here, an effort to systematize different kinds of human bioapatites forming bones, dentin, and enamel was undertaken. The precursors of bioapatites and hydroxyapatite were also considered. The rigorous consideration of compositions and stoichiometry of bioapatites allowed us to establish an order in their mutual sequence. The chemical reactions describing potential transformations of biomaterials from octacalcium phosphate into hydroxyapatite via all intermediate stages were postulated. Regardless of whether the reactions occur in reality, all apatite biomaterials behave as if they participate in them. To conserve the charge, additional free charges were introduced, with an assumed meaning to be joined with the defects. The distribution of defects was coupled with the values of crystallographic parameters “a” and “c”. The energetic balances of bioapatite transformations were calculated. The apatite biomaterials are surprisingly regular structures with non-integer stoichiometric coefficients. The results presented here will be helpful for the further design and development of nanomaterials.
Microscopic Droplet Size Analysis (MDSA) of “Five Thieves’ Oil” (Olejek Pięciu Złodziei) Essential Oil after the Nebulization Process
Nowadays, due to a higher resistance to drugs, antibiotics, and antiviral medicaments, new ways of fighting pathogens are intensively studied. The alternatives for synthesized compositions are natural products, most of which have been known in natural medicine for a long time. One of the best-known and intensively investigated groups are essential oils (EOs) and their compositions. However, it is worth noting that the method of application can play a second crucial part in the effectiveness of the antimicrobial activity. EOs possess various natural compounds which exhibit antimicrobial activity. One of the compositions which is based on the five main ingredients of eucalyptus, cinnamon, clove, rosemary, and lemon is named “five thieves’ oil” (Polish name: olejek pięciu złodziei) (5TO) and is used in natural medicine. In this study, we focused on the droplet size distribution of 5TO during the nebulization process, evaluated by the microscopic droplet size analysis (MDSA) method. Furthermore, viscosity studies, as well as UV-Vis of the 5TO suspensions in medical solvents such as physiological salt and hyaluronic acid, were presented, along with measurements of refractive index, turbidity, pH, contact angle, and surface tension. Additional studies on the biological activity of 5TO solutions were made on the P. aeruginosa strain NFT3. This study opens a way for the possible use of 5TO solutions or emulsion systems for active antimicrobial applications, i.e., for surface spraying.