- ItemOpen AccessUnraveling the chemical changes induced on human meniscus by ostoearthritis using micro-Raman spectroscopy(2014-06-08)Human meniscus a crescent-shaped fibrocartilagenous structure that divides partly the knee joint cavity and is vulnerable to chemical changes caused by pathological conditions. Osteoarthritis is characterized by degeneration of cartilage, precipitation of inorganic crystals and overall deterioration of structure. micro-Raman spectroscopy, a non destructive vibrational technique with in vivo capabilities, yielding information on chemical composition of the irradiated specimen, was employed as a tool to detect chemical changes on human meniscal samples. The spectra were obtained from various spots on the specimen surface, under the same conditions. The existence of collagen type I was detected on the severely osteoarthritic areas along with dermatan sulfate, while the existence of collagen type II with chondroitin sulfate was found on the majority of the spectra obtained. Coexistence of collagen type I and collagen type II was also observed on a small proportion of the spectra obtained. Bioapatite and calcite crystals were also detected on the rim of our sample.
- ItemOpen AccessUsing Raman spectroscopy for the study of biogenic materials(2012-05-04)Raman spectroscopy (RS) is a valuable tool for non-destructive qualitative and quantitative analysis of numerous biogenic materials. Characteristic examples are presented in this work and include characterization of urinary stones, encrusted deposits of stents and bone tissue. In the case of urinary stones the application of RS was capable of analyzing the mineral components of different layers of a urinary stone and the results were compared to those obtained by Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). FTIR and RS were also used in order to characterise the encrusted deposits formed onto a metallic thermosensitive prostatic stent. In the third example FT-Raman spectroscopy was used to assess the compositional changes that were induced by ovariectomy to tibiae of female wistar rats. It was found that the mineral and organic phase Raman intensities of the osteoporotic bones reduced compared to healthy controls, following the same trend as the values obtained from the application of peripheral quantitative computer tomography on the same bones proving that Raman spectroscopy can be an additional valuable tool for studying osteoporosis.
- ItemOpen AccessRaman spectroscopy: a tool for the characterization of plant mineral deposits(2012-05-04)Calcium salts of oxalate and carbonate are common crystalline mineral deposits in plant tissues. Calcium oxalate occurs in the vacuoles of specialized idioblastic cells (crystal cells) while calcium carbonate usually forms amorphous deposits called cystoliths. Characterization of the substances present in a crystal cell or in a lithocyst is an important step in deciphering the metabolic interactions between these mineral deposits and the plant cells. Different methods have been used for their characterization including scanning electron microscopy techniques, powder diffraction X-ray analysis, X-ray absorption spectroscopy, and infrared spectroscopy. Application of the above-mentioned techniques is usually complicated and destructive for the specimen. In the present work, Raman spectroscopy, a non-destructive vibrational technique, was applied on cystoliths that were isolated from Morus alba leaves and crystals isolated from Amaranthus hybridus. It was found that the cystoliths from Morus contained mainly calcium carbonate while the crystals from Amaranthus were made almost exclusively of calcium oxalate monohydrate. Differences in the Raman spectra were observed during leaf development, indicating that Raman spectroscopy can be a valuable tool in the search for the role of cystoliths.
- ItemOpen AccessIdentification of drug polymorphs in tablets(2012-05-04)Polymorphs of an Active Pharmaceutical Ingredient (API) can have different chemical and physical properties and, thus, a direct impact on the process-ability of the drug substance and the quality/performance of the drug product, such as stability, dissolution, and bioavailability. Therefore, identification of the crystal phase of an API is of outmost importance. In this work methodologies were developed based on X-ray powder diffraction and IR for the identification of the crystal phase of two APIs (Atorvastatin Calcium and Donepezil HCl) in commercial tablets.
- ItemOpen AccessEffect of dilipidization and deproteination protocols of bone on biological apatite(2012-05-04)Delipidization and deproteination methods are essential for the isolation of the mineral phase of bone, the biological apatite. In the present work, the effect of the above methods on the crystal size and crystallinity of bone mineral was studied. Ten bovine bones were subjected to these protocols and their crystal size and crystallinity were determined by X-ray Diffraction. In all cases, the delipidization protocol was found not to affect these parameters. On the other hand, deproteination method induces noteworthy changes. All the results statistically tested for their significance.